review article the minos experiment: results and prospects
TRANSCRIPT
Hindawi Publishing CorporationAdvances in High Energy PhysicsVolume 2013 Article ID 182537 18 pageshttpdxdoiorg1011552013182537
Review ArticleThe MINOS Experiment Results and Prospects
J J Evans
Department of Physics and Astronomy University of Manchester Oxford Road Manchester M13 9PL UK
Correspondence should be addressed to J J Evans justinevanshepmanchesteracuk
Received 27 June 2013 Accepted 16 September 2013
Academic Editor Leslie Camilleri
Copyright copy 2013 J J Evans This is an open access article distributed under the Creative Commons Attribution License whichpermits unrestricted use distribution and reproduction in any medium provided the original work is properly cited
TheMINOS experiment has used the worldrsquos most powerful neutrino beam to make precision neutrino oscillation measurementsBy observing the disappearance of muon neutrinos MINOS has made the worldrsquos most precise measurement of the larger neutrinomass splitting and has measured the neutrino mixing angle 120579
23 Using a dedicated antineutrino beam MINOS has made the first
direct precision measurements of the corresponding antineutrino parameters A search for ]119890and ]
119890appearance has enabled a
measurement of the mixing angle 12057913 A measurement of the neutral-current interaction rate has confirmed oscillation between
three active neutrino flavours MINOS will continue as MINOS+ in an upgraded beam with higher energy and intensity allowingprecision tests of the three-flavour neutrino oscillation picture in particular a very sensitive search for the existence of sterileneutrinos
1 Introduction
The MINOS experiment as an idea was conceived in thelate 1990s [1] This was a very important period in neutrinooscillation physics For thirty years results from Homestake[2] and the gallium experiments [3 4] through to a num-ber of atmospheric neutrino detectors [5ndash10] had shownthat neutrinos behaved in an odd fashion often showingsignificant deficits from the expected flux but none hadconclusively determined the mechanism responsible Thenin 1998 Super-Kamiokande [11] proved decisively that muonneutrinos produced in the Earthrsquos atmosphere disappeared asthey traveled Around three years later the SNO experimentshowed conclusively that neutrinos as they propagatedchanged between their three flavours [12 13] This discoveryof neutrino flavour change showed that neutrinos had massand did not conserve lepton number it was the first and stillthe only observation of physics beyond the standard model
It was during this period of discovery that the MINOSexperiment was proposed to begin an era of precisionmeasurement of this new phenomenon The data at the timewere well modeled by the theory of neutrino oscillation inwhich the rate of oscillation between the three flavours isgoverned by the differences between the squared neutrinomasses Δ1198982
21 and Δ119898
2
32 The magnitude of the flavour
change is governed by three mixing angles 12057912 12057923 and
12057913 and a CP-violating phase 120575 these parameters form the
PMNS rotation matrix [14ndash16] that relates the neutrino masseigenstates to the flavour eigenstates Nature has decreedthat the two mass splittings differ by more than an order ofmagnitude and that one of the mixing angles 120579
13 is small
Therefore oscillation phenomenology can be divided intotwo distinct regimes ldquosolarrdquo oscillation driven by Δ1198982
21and
12057912
and ldquoatmosphericrdquo oscillation driven by Δ119898232
and 12057923
MINOS was designed to make precision measurements ofthe parameters governing the atmospheric oscillation regimehowever it has also played a role in the measurement of12057913
and will in the future make sensitive searches for theexistence of sterile neutrinos An important feature of theMINOS design is the ability of the detectors to identify both]120583and ]120583interactions separatelyThis has allowedMINOS to
make the first direct precision tests that the values of Δ119898232
and 12057923are the same for neutrinos and antineutrinos [17ndash20]
To achieve its goals the MINOS experiment uses theworldrsquos most powerful neutrino beam the NuMI beam Tomake best use of this beam the experiment has pioneereda number of techniques associated with the use of the two-detector arrangement over very long baselines which is nowthe gold standard for all neutrino oscillation experiments
2 Advances in High Energy Physics
Target hall Evacuated pipeTarget
Protons frommain injector
10m 30m 675m5m
12m 18m
Rock
Beam stop
Pion (120587+
120587+
120587+
)Muon (120583+)
Muon monitors
120583+
120583+
300mHadron (pion) monitor
Horn 1 Horn 2120592
120592
120592
Figure 1 The NuMI beam
2 The MINOS Experiment
The NuMI facility [21] provides MINOS with an intensebeam of muon flavoured neutrinos at energies of a few GeVThe atmospheric neutrino mass splitting drives oscillationpredominantly between muon and tau flavour neutrinos theenergy dependence of themuonneutrino survival probabilityis given by
119875 (]120583997888rarr ]120583)
= 1 minus sin2 (2120579) sin2(127Δ119898
2[eV2] 119871 [km]
119864 [GeV])
(1)
In this two-flavour approximation Δ1198982 is an admixture ofΔ1198982
32and Δ1198982
31 120579 is also an admixture of the mixing angles
but is heavily dominated by 12057923 SinceMINOS cannot observe
the ]120591appearance it is the measurement of this ]
120583survival
probability that is used to determine the parameters 120579 andΔ1198982 [20 22ndash25]A nonzero 120579
13causes a small amount of ]
119890appearance in
the beam with an energy dependence given by
119875 (]120583997888rarr ]119890)
asymp sin2 (12057923) sin2 (2120579
13) sin2(
127Δ1198982[eV2] 119871 [km]
119864 [GeV])
(2)
MINOS has selected a sample of ]119890-enhanced events to make
a measurement of 12057913[26ndash29]
An important signature of neutrino oscillation is thatthe rate of neutral-current (NC) neutrino interactions isunchanged by the process The NC interaction is equallysensitive to all three neutrino flavours so this proves thatflavour change is occurring between the three active neutrinoflavours By analysing NC interactions MINOS has con-firmed that oscillation is the correct picture and has shownno evidence that this oscillation includes additional sterileneutrino flavours [30ndash32]
The NuMI beam [21] based at Fermilab in Chicagohas run since 2005 and has reached a typical beam powerof 350 kW The Fermilab main injector produces a 10 120583spulse of around 3 times 1013 protons every 22 s These protonshave an energy of 120GeV and strike a graphite target as
shown in Figure 1 This target has a length of 20 nuclearinteraction lengths and consists of a series of forty-seven2 cm long graphite fins separated by 03mm A shower ofhadrons is produced at the target consisting primarily ofpions with a significant kaon component at higher energiesThese hadrons pass through two parabolic magnetic hornswhich focus either positive or negative hadrons depending onthe direction of the electric current through the horns Thefocused hadrons pass down a 675m long helium filled pipein which they decay to produce a beam of predominantlymuon flavoured neutrinos with a small electron neutrinocomponent from the decays of muons and kaons
Figure 2 shows the composition of the NuMI beamWith the horns configured to focus positive hadrons thespectrum of charged current (CC) interactions observed inthe MINOS near detector at Fermilab consists of 917 ]
120583
70 ]120583 and 13 ]
119890and ]119890 With the horns focusing negative
hadrons the observed CC interactions consist of 399 ]120583
581 ]120583 and 20 ]
119890and ]
119890 The significant difference in
composition and event rate between these two configurationsarises mainly from the fact that the ]
120583interaction cross-
section is approximately a factor of two lower than the ]120583
interaction cross-sectionThe neutrino beam peaks at an energy of close to 3GeV
However the current through the focusing horns and therelative positions of the horns and target are variable allowingthe energy of the beam peak to be varied to as high as 10GeVThis feature has enabledMINOS to study and understand thebeam in detail [33] improving the simulation of the beambeyond the raw Fluka [34] andGEANT [35 36]Monte Carlosand significantly reducing the systematic uncertainty fromthe modeling of the neutrino flux
A total of 1056 times 1020 protons on target of beam data
has been analysed in the neutrino-dominated beam modeThis data corresponds to the beam configuration shown inFigure 2 with the energy spectrum peaking at 3GeV and isreferred to as the low energy beam configuration Additional015times10
20 protons on target of data with a 10GeV beam peakhave also been used In the antineutrino-enhanced beammode a total of 336times1020 protons on target of beamdata havebeen analysed These are the exposures used for all analysespresented in this paper except where otherwise stated andthey were obtained between May 2005 and April 2012
The two MINOS detectors [37] are steel-scintillatorcalorimeters shown in Figure 3 They consist of planes of
Advances in High Energy Physics 3
Neutrino-dominated
True energy (GeV)5 10 15 20 25 300
0
02
04
06
08
1
Near detector simulated Low energy beam
Flux
times120590
CC
(au
)
120583 spectrum120583 spectrum
(a)
True energy (GeV)5 10 15 20 25 300
0
02
04
06
08
1
Near detector simulatedLow energy beam
Antineutrino-enhanced
Flux
times120590
CC
(au
)
120583 spectrum120583 spectrum
(b)
Figure 2The composition of theNuMIbeamwhen configured to produce (a) a neutrino-dominated beamand (b) an antineutrino-enhancedbeam The figures show the rate of charged current neutrino interactions observed in the MINOS near detector
(a) (b)
Figure 3 The MINOS detectors (a) the near detector at Fermilab (b) the far detector at the Soudan Underground Laboratory
inch-thick steel interleaved with planes of 1 cm thick plasticscintillator The scintillator planes are divided into 4 cm widestrips as shown in Figure 4 Along the centre of each strip awavelength shifting fibre collects the scintillation light shiftsit to green wavelengths and takes it out to a photomultipliertube Any charged particles passing through the detectordeposit their energy to produce light the pattern of thesedeposits allows the topology of the neutrino interaction to bereconstructedThe scintillator strips are aligned orthogonallyon adjacent detector planes to allow three-dimensionalreconstructionThe detectors are magnetised to around 13 Tallowing the charge of particles to be identified
The smaller of the two detectors the Near Detector(ND) sits at Fermilab 104 km from the target With amass of 098 kton it measures the energy spectra of theneutrinos before oscillation The far detector is located atthe SoudanUndergroundLaboratory in northernMinnesota705m underground and 735 km from the target With a massof 54 kton it again measures the neutrino energy spectra
seeing the appearance and disappearance of neutrinos due tooscillation
This two-detector arrangement previously used overdistances of around 1 km by experiments such as CCFRCDHS and CHARM [38ndash40] and then over 250 km by K2K[41] is very powerful in reducing systematic uncertaintiesNeutrino physics is beset with uncertainty in particularinteraction cross-sections are unknown to many tens of percent and neutrino fluxes can be mismodeled by similaramounts However these uncertainties affect both the nearand far detectors in very similar ways Thus when a ratio istaken of the energy spectra measured in the two detectorsa cancellation occurs and the effects of the uncertainties aregreatly reduced As an indication of how well this worksdespite the uncertainties of tens of per cent in the simulatedevent rate in the detectors once the near to far detector ratiois taken the normalization is known to 16 this 16 isdominated by the uncertainty in the relative efficiency of theevent reconstruction algorithms between the two detectors
4 Advances in High Energy Physics
PMT assembly
CookieMUX box optical
connectorOptical cable
MUX box
Optical connector
WLS fibers
Scintillator strips
Steel plates
Figure 4 A MINOS detector plane
The MINOS Far Detector is also a very effective detectorof neutrinos produced in the atmosphere Since it wasswitched on in 2003 it has recorded 379 kton-years of datarecording 2072 candidate neutrino interactions that havebeen included into the analyses of the beam data to improvethe precision of the oscillation parameter measurements [2042ndash44]
3 Neutrino Interactions inthe MINOS Detectors
Three types of neutrino interaction shown in Figure 5 areof interest to MINOS Muon neutrinos and antineutrinosinteract through the CC process
]120583(]120583) + 119883 997888rarr 120583
minus(+)+ 1198831015840 (3)
The cascade of hadrons 1198831015840 produces a diffuse shower ofenergy deposits near the interaction vertex The muon pro-duces a long track that curves in the magnetic field thedirection of curvature identifying the incoming neutrino asa ]120583or a ]120583
All active neutrino flavours undergo NC interactionsthrough the process
] + 119883 997888rarr ] + 1198831015840 (4)
Only the hadronic cascade is observed producing a diffuseshower of energy deposits
Finally electron neutrinos undergo CC interactionsthrough the process
]119890+ 119883 997888rarr 119890
minus+ 1198831015840 (5)
The electron gives rise to an electromagnetic shower whichproduces a much denser more compact shower of energydeposits
The energy of the neutrino is determined by summing theenergies of the shower and anymuon trackThemuon energyis determined from the length of stopping tracks leading toa resolution of around 5 and from the curvature in themagnetic field for tracks that exit the detector leading to aresolution of around 10 For NC and ]
119890CC interactions
the energy of the shower is determined through calorimetryThe calorimetric energy resolution for hadronic showers isaround 55radicenergy [45] and for electromagnetic showers20radicenergy [46] For ]120583 CC interactions a more sophisti-cated approach is used to improve the resolution of hadronicshower energy measurement [47] For low energy showers(of a few GeV or below) significant additional information isheld in the topology of the showerThree event characteristicsare used the calorimetric energy deposit within 1m of theinteraction vertex the sum of the calorimetric energy in thetwo largest showers in the event and the physical length ofthe largest shower These variables are input into a 119896-nearest-neighbour algorithm [48] which finds the best matches froma library of simulated events and uses these to estimate thehadronic energyThis improves the shower energy resolutionfrom 55 to 43 for showers between 10GeV and 15 GeV
31 Selection of Charged-Current ]120583and ]
120583Interactions To
make a measurement of 119875(]120583
rarr ]120583) it is necessary to
select a pure sample of ]120583CC interactions This is achieved
by selecting events with a clear muon track The main loss inefficiency comes from events with a high inelasticity in whicha short muon track is hidden in a large hadronic cascade
Advances in High Energy Physics 5
CC 120583 event
120583minus
15
1
05
0
0
05 1 15 2 25 3 35 4
Longitudinal position (m)
Tran
sver
se p
ositi
on (m
)
minus05
(a)
V
06
04
02
0
minus02
minus02
minus04
minus04
minus06
0 02 04 06 08 1
NC event
Longitudinal position (m)
Tran
sver
se p
ositi
on (m
)
(b)
e
02
0
02
0 05 1
CC e event
Longitudinal position (m)
Tran
sver
se p
ositi
on (m
)
lowast
(c)
Figure 5 Neutrino interaction topologies observed in the MINOS detectors (a) A CC ]120583interaction (b) A NC interaction (c) A CC ]
119890
interaction Each coloured rectangle represents an excited scintillator strip the colour indicating the amount of light purple and blue are lowlight levels through to orange and red for the highest light levels
The main background occurs at low energies and consists ofsmall cascades from NC interactions in which a low energyhadron such as a proton or a charged pion exhibits a track-like topology that mimics a low energy muon Four variablesare constructed that discriminate between muons trackswhich are typically long and show a constant energy deposi-tion along the length and spurious hadronic tracks which aretypically shorter and show greater fluctuations in the energydeposition These variables are the event length the averageenergy deposited per scintillator plane along the track thetransverse energy deposition profile and the fluctuation of
the energy deposition along the track These variables areinput into a 119896-nearest-neighbour algorithm which calculatesa single discrimination variable shown in Figure 6 [49]Events for which this variable is greater than 03 are selectedas CC ]
120583interactions yielding a sample with a total efficiency
of 90 below 2GeV the NC contamination is 65 Theefficiency and contamination are energy dependent this fullenergy dependence is shown in Figure 6
The CC interactions of ]120583and ]
120583result in very similar
topologies the 119896-nearest-neighbour discriminant is thereforeused in the same way in both the neutrino-dominated and
6 Advances in High Energy Physics
CCNC separation parameter
Low energy beamDataMC expectation
NC background
Even
ts10
16PO
T
10
1
10minus1
10minus2
0 02 04 06 08 1
(a)
Reconstructed neutrino energy (GeV)
0
02
04
06
08
1
NC contamination
Far detector fiducial onlyCC selection efficiency
0 2 4 6 8 10
Effici
ency
con
tam
inat
ion
(b)
Figure 6 (a) The discrimination variable used to separate ]120583CC interactions from hadronic backgrounds Events with a parameter value
greater than 03 are selected as ]120583CC interactions (b) The efficiency and background contamination of the selected ]
120583CC sample in the far
detector
antineutrino-enhanced beams When performing a directmeasurement of the antineutrino oscillation parameters anadditional selection cut is made requiring the charge of themuon track to be positiveThis uses the direction of curvatureof themuon asmeasured by aKalman Filter algorithm [50] Afurther sample of ]
120583CC interactions is obtained from the 7
]120583component in the neutrino-dominated beamThis sample
contains a significant background of ]120583events in which a 120583minus
has been identified with the incorrect charge often at lowenergies where the muon undergoes significant scatteringTherefore a much stricter set of selection criteria are appliedto purify this ]
120583sample [18]
32 Selection of Charged-Current ]119890Interactions The selec-
tion of ]119890CC interactions focuses on identifying the dense
showers from the electromagnetic interaction of the electronrather than the much more diffuse hadronic showers Theprimary background comes from purely hadronic showerswhich can have a denser than average energy depositparticularly in the presence of a neutral pion decaying tophotons Once a set of shower-like events in the signalregion of 1ndash8GeV has been obtained a pattern matchingapproach called library event matching is used to identifythe interactions most likely to be ]
119890CC [51 52] Each event
in the data is compared to a library of 5 times 107 simulated
signal and background events its similarity to the libraryevents is quantified by comparing the pattern of energydeposits in each scintillator strip excited by the shower wherethe energy deposit is quantified by the charge recorded onthe photomultiplier tube For an arbitrary energy depositthe mean expected charge on a photomultiplier tube willbe some value 120582 The probability of observing an amountof charge 119899 is then a Poisson distribution 119875(119899 | 120582) Thelikelihood L of a data event corresponding to the same
physical shower topology as a simulated library event cantherefore be calculated as
logL =
119873strips
sum
119894=1
log [intinfin
0
119875 (119899119894
data | 120582) 119875 (119899119894
lib | 120582) d120582] (6)
where 119894 represents the 119894th scintillator strip in the showerUsing this definition of the likelihood the 50 library eventsare identified that best match the data eventThree quantitiesare calculated from this set of 50 best-matching library eventsthe fraction of the events that are true ]
119890CC events the
average inelasticity of the true ]119890CC events and the average
fraction of charge that overlaps between the data event andeach ]
119890CC library event These three quantities are input to
a neural network which calculates a classification variableshown in Figure 7 Events with a classification variable valueabove 06 are selected for analysis this value was chosen tomaximise the sensitivity to ]
119890and ]119890appearance
The efficiency of the ]119890CC selection is estimated from
the data rather than relying totally on the simulation Toobtain a pure sample of true hadronic showers a sampleof well-identified ]
120583CC events is selected and the energy
depositions corresponding to the muon track are removed[53]The simulated energy depositions of an electron are theninserted [54] providing a realistic sample of ]
119890CC events
Using thismethod the ]119890CC identification efficiency is found
to be (574 plusmn 28) in the neutrino-dominated beam and(633 plusmn 31) in the antineutrino-enhanced beam
33 Selection of Neutral-Current Interactions The signal of anNC interaction is a diffuse hadronic shower ]
120583CC interac-
tions also produce hadronic showers and if the inelasticityis high the tell-tale muon track may not visibly extend pastthe shower To purify a sample of NC interactions a simple
Advances in High Energy Physics 7
sin2(212057913) = 01
Δm232 gt 0 120575cp = 0 12057923 =
120587
4
Background
MINOS far detector80
60
40
20
00 01 02 03 04 05 06 07 08 09 1
LEM discriminant
Signal times10
Even
ts8
2times10
20PO
T
(a)
LEM discriminant
Even
ts10
19PO
T
DataMonte Carlo
MINOS near detector8000
6000
4000
2000
00 01 02 03 04 05 06 07 08 09 1
(b)
Figure 7 (a) The library event matching discriminant showing the expected distribution for background and CC ]119890signal events in the far
detector in the neutrino-dominated beam Note that the signal simulated for sin2(212057913) = 01 120575 = 0 and a normal mass hierarchy has been
scaled up by a factor of ten for visibility (b)The same discriminant as observed in the near detector compared with the simulated expectation
Near detector dataMonte Carlo prediction
20
10
30
50
2018161410 120
0 2 4 6 8
40
60
120583 CC background
Ereco (GeV)
104
even
ts (G
eV)
Figure 8 The sample of events identified as NC interactions in thenear detector
cut-based approach is taken [55] events are classified asNC-like if the event contains no reconstructed track or ifthe track extends no more than six planes past the end ofthe shower The resulting distribution of NC interactions inthe near detector is shown in Figure 8 The NC identificationefficiency is 89 with 61 purity This selection will identify97 of ]
119890CC interactions as NC events therefore an analysis
of NC interactions in the FD must account for the ]119890
appearance caused by a nonzero 12057913
34 Selection of Atmospheric Neutrinos Atmospheric neu-trino interactions are selected out of any activity seen in
the FD outside of the 10 120583s periods when the NuMI beamis active [44] The oscillation signal is contained in the ]
120583
CC interactions and as with the beam-induced interactionsthese are identified by the presence of a muon track The FDbegan taking data with atmospheric neutrinos in July 2003two years before the NuMI beam began running
The FD has a single-hit timing resolution of 25 ns Thistiming information is used to determine the direction inwhich the detector activity is traveling Any downwardstraveling activity is required to begin well inside the detec-tor to eliminate cosmic muons entering from above Allupwards or horizontally traveling activity is almost certainto be neutrino-induced since no other particle can survivethrough the many kilometres of rock All activity with azenith angle of cos 120579
119911lt 014 is defined as horizontal or down-
going this corresponds to an overburden of at least 14 kmwater equivalent
From this sample of neutrino-induced activity all eventswith a track crossing at least eight planes are designatedtrack-like all events with only shower-like activity crossing atleast four planes are designated shower-like These track-likeand shower-like samples are used in the neutrino oscillationmeasurementsThe track-like sample contains the oscillationsignal of ]
120583disappearance The shower-like sample contains
mainly NC interactions and ]119890and ]
119890CC interactions it
shows little oscillation signal but is very important for settingthe normalization of the atmospheric neutrino flux
4 Muon Neutrino andAntineutrino Disappearance
The atmospheric oscillation parameters |Δ1198982| and sin2(2120579)aremeasured by observing and fitting the energy dependenceof ]120583and ]
120583disappearance To minimise the impact of
8 Advances in High Energy Physics
20
40
60
80
100
120
0 10 15 20 30 50
Even
tstimes10
4(G
eV)
MINOS near detector dataMCMC uncertaintyNC background
MINOS near detectorLow energy beam 120583-mode729 times 1020 POT
Reconstructed 120583 energy (GeV)5
Figure 9 The energy spectrum of ]120583CC interactions observed in
the ND compared to the simulation
systematic uncertainties the energy spectra of the ]120583and
]120583CC interactions observed in the ND (shown in Figure 9
for the neutrino-dominated beam) are used to predict thespectrum at the FD in the absence of oscillation [23 56]The neutrino energy spectra at the ND and FD are notidentical the ND subtends a relatively large angle to thebeam so for each pion or kaon a range of decay anglescan produce a neutrino that passes through the detectorcorresponding to a range of neutrino energies However theFD is effectively a point when viewed from the neutrinoproduction location so a single decay angle for each hadrontherefore a single neutrino energy contributes to the fluxTo take this difference into account the hadron-decay kine-matics are encoded into a beam transfer matrix that convertsthe observed ND flux into a predicted FD flux Once theND data has been used in this way the most importantsystematic uncertainties are those that can affect the twodetectors differently primarily reconstruction efficienciesand miscalibrations of the neutrino energy measurementin the detectors [57] These uncertainties are included inthe fit that extracts the oscillation parameters [58] Theuncertainty on the reconstruction efficiency is modeled as a16 uncertainty on the relative rate of events between theND and FD The uncertainty on the measurement of muonenergy has two components that are fully correlated betweenthe detectors a 2 uncertainty on energies measured fromrange and a 3 uncertainty on energies measured fromthe curvature in the magnetic field The uncertainty in thehadronic energy measurements also has two componentsAn uncertainty arising from shower modeling uncertaintiesand calibration is fully correlated between the detectorsand is parameterized as (66 + 35119890119864shw14GeV) The secondcomponent is uncorrelated between the detectors and is 19
in theND and 11 in the FD this is dominated by calibrationuncertainties
The top row of Figure 10 shows the predicted spectra of]120583and ]120583CC interactions from the neutrino-dominated and
antineutrino-enhanced beams at the FD along with the dataIn the neutrino-dominated beam an additional sample isused consisting of neutrinos interacting outside the fiducialvolume of the detector and in the rock surrounding thedetector [59 60] This nonfiducial sample consists mainlyof high energy neutrinos and has significantly lower res-olution as not all the energy is contained in the detectorhowever it does contain some oscillation information Intotal 8100 reconstructed neutrino events are used in theanalysis without oscillations 9471 would be expected Inall samples a clear energy-dependent deficit of ]
120583and
]120583interactions is observed The ratio of the data to the
expectation for the ]120583interactions in the neutrino-dominated
beam is shown in Figure 11This ratio shows the ldquodip and riserdquoenergy dependence of the deficit which is characteristic ofoscillation and described by (1)
The bottom row of Figure 10 shows the spectra of atmo-spheric ]
120583and ]120583CC interactions as a function of 119871119864 where
119871 is the distance traveled by the neutrino and 119864 is its energyThe atmospheric neutrino events are divided into ]
120583and ]120583
interactions according to the direction of curvature of themuon and separated into samples depending on whether ornot the interaction vertex is contained in the detector
All the observed ]120583and ]120583CC interactions are fit accord-
ing to the two-flavour model of (1) under the assumptionthat neutrinos and antineutrinos have the same oscillationparametersThe resultingmeasurement of |Δ1198982| and sin2(2120579)is shown in Figure 12 The fit yields |Δ1198982| = (241
+009
minus010) times
10minus3 eV2 and sin2(2120579) = 0950
+0035
minus0036 disfavouring maximal
mixing at the 86 confidence level Figure 12 compares thismeasurement to those from Super-Kamiokande [61] andT2K [62] The MINOS measurement is the most precisedetermination of |Δ1198982| and all measurements of sin2(2120579) areconsistent
41 Muon Antineutrino Disappearance In the standardmodel of neutrino oscillation neutrinos and antineutrinosobey the same parameters with CPT symmetry requiringthat the masses of particles and antiparticles are identicalThe most sensitive test of this symmetry in other sectors isfrom the kaon system [63] The data from the antineutrino-enhanced beam and the interaction of atmospheric antineu-trinos enables the first direct comparison of the neutrinoand antineutrino oscillation parameters in the atmosphericregion This comparison provides a limit on nonstandardinteractions with the matter being passed through by theneutrino beam [64ndash70]
Figure 10 showed the energy spectra of ]120583interactions
observed in the FD These spectra can be fit in the two-flavour model of (1) allowing the antineutrino oscillationparameters to differ from those for neutrinos This fit yieldsthe antineutrino parametermeasurement shown in Figure 13|Δ1198982| = (250
+023
minus025) times 10
minus3 eV2 and sin2(2120579) = 097+003
minus008
This is in excellent agreement with the parameters measured
Advances in High Energy Physics 9
Neutrino energy (GeV) Neutrino energy (GeV) Neutrino energy (GeV)
0
20
40
60
80
0
5
10
10
15
1515
20
20
25
25
30
Muon energy (GeV)
0
200
400
600
800
0
100
200
300
400
500
6001071 times 1020 POT
Even
ts (G
eV)
Even
ts (G
eV)
Even
ts (G
eV)
Even
ts (G
eV)
120583 120583
120583120583
0 02 4 56 0 2 4 68 910 12 14 0 2 4 6 8 10 12 14
Neutrino beam Neutrino beam Neutrino beam Antineutrino beam
contained-vertex 120583
nonfiducial 120583contained-vertex 120583
contained-vertex 120583 336 times 1020 POT
(a)
0
20
40
60
0
10
20
30
0
10
20
30
0
5
10
15
20
25
MINOS dataBest fit oscillationsNo oscillations
NC backgroundCosmic-ray muons
120583 120583 120583 120583
0 1 2 3 4 0 1 2 3 4 0 1 2 3 4 0 1 2 3 4
Even
ts
Even
ts
Even
ts
Even
ts
Atmos contained-vertex 120583 Atmos nonfiducial 120583minus Atmos nonfiducial 120583+3788kton-years
Atmos contained-vertex 120583
log10( (km)E (GeV)) log10( (km)E120583 (GeV))L L log10( (km)E (GeV))L log10( (km)E120583 (GeV))L
(b)
Figure 10 The energy spectra of ]120583and ]
120583CC interactions observed at the FD compared to the expectation with and without oscillation
(a) shows beam-induced neutrinos (b) shows atmospheric neutrinos
with neutrinos alone (the red line in Figure 13) It should benoted that the first MINOS measurement of the antineutrinooscillation parameters released in 2010 [17] yielded a notabletension between the ] and ] oscillation parameters whichwere in agreement only at the 20 confidence levelThis ten-sion was shown to be a statistical fluctuation as the additionof further data brought the ] and ] parameters measurementsinto good agreement [19 20]
5 Electron Neutrino andAntineutrino Appearance
A search for ]119890and ]
119890appearance in the ]
120583and ]
120583beams
enables a measurement of the mixing angle 12057913 It is critical
to know the level of background to the ]119890sample in the
FD The energy spectrum of background events measured inthe ND is used to predict the spectrum expected in the FDHowever the background consists of three components NCinteractions CC ]
120583and ]
120583interactions and the intrinsic ]
119890
component in the beam The relative contribution betweenthe ND and FD is different for all of these components sincethey are affected differently by oscillation and the kinematicsof the production in the beam are different Therefore each
backgroundmust be individually measuredTheNuMI beamcan be configured to produce neutrino beams of varyingenergy by altering the current passing through the magnetichorns and changing the relative positions of the target andhorns Between these different beam configurations therelative contributions of the three background componentschange in a well-understood way as shown in Figure 15By comparing the ND data to the simulation in the threedifferent beam configurations shown in the figure the contri-butions of the three background components can be extracted[71]
Using the data-driven background extraction procedurea total of 1277 background events are expected at the FDin the neutrino-dominated beam and 175 events in theantineutrino-enhanced beam In the data 152 and 20 eventsare observed respectively Figure 16 shows the energy spectraof these events divided into bins of the library eventmatchingdiscriminant variable Although CC ]
119890and ]119890events cannot
be separated on an event-by-event basis the change inthe relative numbers of neutrino and antineutrino inter-actions between the neutrino-dominated and antineutrino-enhanced beams is well knownThis allows separate limits tobe placed on the rates of ]
120583rarr ]119890and ]120583rarr ]119890transitions
on a statistical basis
10 Advances in High Energy PhysicsRa
tio to
no
osci
llatio
ns
05
1
15
2
25
0 10 15 20 30 50
MINOS far detector data
5Reconstructed 120583 energy (GeV)
1071 times 1020 POT
Prediction Δm2 = 241 times 10minus3eV2
Low energy beam 120583-mode
Figure 11 The ratio of the observed ]120583energy spectrum to the
expectation in the case of no oscillation in the neutrino-dominatedbeam The black points show the data the blue line shows the bestfit to the data
075 080 085 090 095 10015
20
25
30
35
40
90 CL68 CL
90 CL
sin2(2120579)
|Δm
2|(10minus3eV
2)
MINOS 3788 kt-yr atmospheric
336 times 1020 POT 120583 modeSuper-K zenith anglelowast
Super-K LElowast
T2Klowastlowast
lowastNeutrino 2012lowastlowastPRD 85 031103(R) (2012)
1071 times 1020 POT 120583 mode
Figure 12 The allowed regions for the atmospheric oscillationparameters |Δ1198982| and sin2(2120579) assuming identical neutrino andantineutrino oscillation parametersTheMINOS result is comparedto measurements from Super-Kamiokande [61] and T2K [62]
The data are fit to extract a measurement of 12057913 The
resulting measurement is shown in Figure 17 The measuredvalue of 120579
13depends on the CP violating phase 120575 which
directly affects the ]119890and ]
119890appearance probabilities and
themass hierarchy which affects the appearance probabilitiesthrough the interactions of the neutrinos with the matter in
MINOS 120583 disappearance1071 times 1020 POT 120583 mode336 times 1020 POT mode3788kt-yr atmospheric
90 CL120583120583120583 + 120583
120583120583120583 + 120583
Best fit
sin2(2120579) or sin2(2120579)
(|Δm
2|
or Δ
m2|)
(10minus3eV
2)
075 080 085 090 095 100
20
25
30
35
120583
|Figure 13 The allowed region for antineutrino oscillation param-eters (blue line) compared to the region measured with neutrinosalone (red line) and the region measured using both neutrinos andantineutrinos under the assumption they have the same parameters(black line)
20
25
30
20 25 30
|Δm
2| (10
minus3eV
2)
|Δm2| (10minus3eV2)
68 CL|Δm2| = |Δm2|
MINOS 120583 disappearance1071 times 1020 POT 120583 mode336 times 1020 POT mode3788kt-yr atmospheric
90 CLBest fit
120583
Figure 14 A comparison of the measured limits on the masssplittings of neutrinos and antineutrinos
the Earthrsquos crust Assuming a normal mass hierarchy 120575 = 0and 120579
23lt 1205874 MINOS measures 2sin2(2120579
13)sin2(120579
23) =
0051+0038
minus0030 Assuming an inverted mass hierarchy 120575 = 0
and 12057923
lt 1205874 MINOS measures 2sin2(212057913)sin2(120579
23) =
0093+0054
minus0049 This measurement is consistent with the results
from reactor neutrino searches [72ndash74] and the T2K experi-ment [75]
This MINOS measurement is the first ever search for ]119890
appearance in a long-baseline ]120583beam and the first search
Advances in High Energy Physics 11
Reconstructed energy (GeV)0 6 8
Frac
tion
of ev
ents
0
01
02
03
04
Standard MC
MINOS
2 4
Near detector 2011
NC120583-CCe-CC
(a)
Horn-off MC
Reconstructed energy (GeV)0 6 8
Frac
tion
of ev
ents
0
01
02
03
04 MINOS
2 4
Near detector 2011
NC120583-CCe-CC
(b)
High energy MC
Reconstructed energy (GeV)0 6 8
Frac
tion
of ev
ents
0
01
02
03
04 MINOS
2 4
Near detector 2011
NC120583-CCe-CC
(c)
Figure 15 The contribution of the three components to the background in the ]119890appearance search as simulated in the ND (a) the regular
(low energy) beam data (b) with no current in the NuMI focusing horns (c) a high energy beam configuration
for ]119890and ]119890appearance with significant matter effects Both
of these effects provide some sensitivity to the neutrinomass hierarchy and CP violation when the MINOS data iscompared to the measurements made by reactor neutrinosearches [72ndash74] (we have calculated a limit of sin2(2120579
13) =
0098 plusmn 0013 from the reactor data at the time of analysis)The sensitivity of MINOS to the mass hierarchy and CPviolation is modest but this contributes to the first analysisof the type that will be used by all future long-baselineexperiments The resulting values of the likelihood by whichMINOS disfavours various values of these parameters areshown in Figure 18 [76]
6 Search for Sterile Neutrino Mixing UsingNeutral-Current Interactions
The energy spectrum of NC interactions in the FD should beunchanged by standard neutrino oscillationThe existence ofone or more sterile neutrino flavours ]
119904 could cause a deficit
in the observed NC interaction rate As with all the MINOSoscillation analyses the energy spectrum of NC interactionsobserved in the ND (which was shown in Figure 8) is usedto predict the spectrum expected at the FD [77] The FDexpectation is shown in Figure 19 with the dashed blue linetaking into account ]
119890appearance corresponding to 120579
13=
115∘ (at the limit set by CHOOZ [78] and a little above
the current accepted value [29 72ndash75] this analysis usesonly the first 707 times 10
20 protons on target of data andwas performed before the recent positive measurements ofa nonzero 120579
13) The data are also shown in the figure and
are in good agreement with the expectation confirming thestandard model of neutrino oscillation This agreement canbe quantified using a test statistic 119877
119877 =119873data minus 119861CC
119878NC (7)
where 119873data is the number of events observed 119861CC is thepredicted background of CC interactions and 119878NC is the
predicted number of NC interactions A value of 119877 = 101 plusmn
006(stat) plusmn 005(syst) is obtained (over the full energy range0ndash120GeV) which is in good agreement with the expectationof 119877 = 1 in the case of no mixing with sterile neutrinos
The data are analysed with a model that assumes a singlesterile neutrino flavour mixing through the addition of afourth neutrino mass state119898
4≫ 1198983 This introduces a mass
splitting Δ119898243
with magnitude O(1 eV2) such that no oscil-lation-induced change to the event rate is observed at theND and the oscillatory energy dependence of the induceddepletion at the FD is so rapid that an overall uniform deple-tion is observed once the energy resolution of the detectors isaccounted forThismodel introduces three additionalmixingangles 120579
14 12057924 and 120579
34 MINOS is insensitive to 120579
14but sets
limits of 12057924= (00
+5
minus00)∘ and 120579
34= (00
+25
minus00)∘ These limits are
evaluated assuming 12057913at the CHOOZ limit
The limit on the coupling of sterile to active neutrinos canbe quantified by defining 119891
119904 the fraction of disappearing ]
120583
which have oscillated into ]119904
119891119904=
119875]120583rarr ]119904
1 minus 119875]120583rarr ]120583
(8)
For the model used in which 1198984≫ 119898
3 119891119904is evaluated
at 14 GeV the energy of maximal ]120583disappearance To
determine the limit on 119891119904 a large number of test values
are chosen of the mixing angles 12057924 12057934 and 120579
23 from
Gaussian distributions according to the measured values and1120590 uncertainties given above (with 120579
23constrained from the
measurements with CC ]120583interactions) 119891
119904is calculated for
each case and the value of 119891119904that is larger than 90 of the
test cases represents the limit MINOS limits 119891119904lt 040 at the
90 confidence level
7 The Future MINOS+
The MINOS experiment has made some very importantcontributions to our understanding of neutrino oscillation
12 Advances in High Energy Physics
Reconstructed energy (GeV)
Reconstructed energy (GeV)
Even
ts
30
0
10
20
Even
ts
30
0
10
20
Even
ts
30
0
10
20
2 4 6 8
2 4 6 8
Reconstructed energy (GeV)2 4 6 8
06 lt 120572LEM lt 07
MINOS far detector data
07 lt 120572LEM lt 08
120572LEM gt 08
mode
mode
mode
e CC signal
e CC signalBackgroundData
(a)
Even
ts
Reconstructed energy (GeV)2 4 6 8
Reconstructed energy (GeV)2 4 6 8
Reconstructed energy (GeV)2 4 6 8
06 lt 120572LEM lt 07
MINOS far detector data
Merged for fit
07 lt 120572LEM lt 08
120572LEM gt 08
mode
mode
mode
8
6
4
2
0
Even
ts
8
6
4
2
0
Even
ts
8
6
4
2
0
e CC signal
e CC signalBackgroundData
5ndash8GeV bins
(b)
Figure 16 The CC ]119890(a) and ]
119890(b) candidate events selected in the FD compared to the expectation without any ]
119890appearance (red) and
with the best fit for 12057913(purple) The events are divided into bins of the library event matching discriminant variable
Advances in High Energy Physics 13
20
15
10
05
000 01 02 03 04
2sin2(212057913)sin212057923
Δm2 gt 0
sin
120575(120587)
(a)
20
15
10
05
000 01 02 03 04
2sin2(212057913)sin212057923
MINOS best fit 12057923 lt 1205874
MINOS best fit 12057923 gt 1205874
Δm2 lt 0
MINOS
106 times 1020 POT -mode33 times 1020 POT -mode
68 CL 12057923 lt 1205874
90 CL 12057923 lt 1205874
120575(120587)
(b)
Figure 17 The allowed regions for 2sin2(212057913)sin2(120579
23)
120575(120587)
Δm2 gt 0 12057923 gt 1205874
Δm2 gt 0 12057923 lt 1205874
Δm2 lt 0 12057923 gt 1205874Δm2 lt 0 12057923 lt 1205874
3
2
1
00 1 1505 2
MINOS
90 CL
68 CL
minus2Δ
(L)
ln
Figure 18 The values of likelihood 119871 by which various values oftheCP violating parameter 120575 the mass hierarchy and the octant of12057923are disfavouredThis analysis uses MINOS data and information
from reactor neutrino measurements of 12057913[72ndash74]
physics and has finished taking data with the low energybeam for which it was designed However the experimentwill continue taking data and producing new results for thenext few years as MINOS+ [79] The NuMI beam is being
20
2018161410 12
Far detector data
Even
ts (G
eV)
00 2 4 6 8
40
60
80
100
120
140
12057913 = 0∘
12057913 = 115∘ 120575 = 120587 Δm232 gt 0
120583 CC background|Δm2
32| = 232 times 10minus3eV2
Ereco (GeV)
sin2212057923 = 1
Figure 19 The black dots show the energy spectrum of NCinteractions observed in the far detector The red lines show theexpectation in the case of no sterile neutrinos and 120579
13= 0 the blue
dashed line shows the same expectation with 12057913= 115
∘
upgraded to a higher energy and intensity for the NO]Aexperiment the far detector of which will sit 14 mrad offaxisNO]A will receive a narrow-band beam peaking at around2GeV which is ideal for searching for ]
119890appearance since
the background seen in MINOS from NC interactions ofhigh energy neutrinos will be heavily reduced Figure 20shows that the MINOS FD will see an intense ]
120583beam
14 Advances in High Energy Physics
1000
500
00 5 10 15 20
E (GeV)
MINOS+NOAMINOS
Preliminary
Simulated beam54 kton 6 times 1020 POT
120583CC
even
ts (G
eV)
Figure 20 The ]120583energy spectrum that will be observed by the
MINOS+ FD compared to the spectra observed by MINOS andNO]A
peaking at around 7GeV In this configuration MINOS+ willobserve around 4000 CC ]
120583interactions in the FD each
year unprecedented statistics for a long-baseline oscillationexperimentThis will offer a unique high precision test of thethree-flavour oscillation paradigm
MINOS+ will be able to make a very sensitive searchfor the sterile neutrinos suggested by the LSND [80] andMiniBooNE [81 82] data and by some interpretations ofreactor neutrino data [83] This search will cover more thanthree orders of magnitude in the mass splitting between thesterile and active neutrinos The signal that MINOS+ willsearch for is illustrated in Figure 21 Figure 21(a) illustratesthe increase in statistical precision thatMINOS+will provideon the ratio of the observed CC ]
120583interaction rate to
that expected without oscillations Figure 21(b) shows howthis ratio is modified if a sterile neutrino exists and mixeswith the active neutrinos an additional deficit of muonneutrino interactions occurs in the higher energy region ofthe spectrum In the model assumed here which introducesa single sterile neutrino state three new mixing angles areintroduced 120579
14 12057924 and 120579
34 An additional mass splitting
Δ1198982
43is also introduced The position in energy of the
additional deficit is governed by the value of the new masssplittingThemagnitude of the additional deficit in the CC ]
120583
interaction rate is governed primarily by the size of 12057924 this is
in comparison to short-baseline searches for ]119890disappearance
from reactors which are governed by 12057914and searches for ]
119890
appearance in ]120583beamswhich are governed by a combination
of 12057914
and 12057924 A detailed explanation of the global effort to
search for sterile neutrinos can be found in [84]The sensitivity of the MINOS+ experiment when com-
bined with the Bugey reactor neutrino data [85] is shown in
MINOS+ simulation
MINOS 1071 times 1021 POT06 times 1021 POT12 times 1021 POT18 times 1021 POT
120583su
rviv
al p
roba
bilit
y
Neutrino energy (GeV)0 5 10 15
15
1
05
0
(a)
P(
120583rarr
120583)
No sterile neutrinosΔm2
43 = 2 times 10minus2eV2 sin2(212057924) = 02
0 5 10 15 20
1
0
18
06
04
02
Neutrino energy (GeV)
(b)
Figure 21 (a) The black points show the ratio of the observed ]120583
energy spectrum to the expectation in the case of no oscillation inthe neutrino-dominated beam of MINOS The blue region showsthe statistical precision expected from MINOS+ (b) The black lineshows the muon neutrino survival probability in the case of nosterile neutrinos the red line shows how the probability would bemodified by the addition of mixing with a sterile neutrino
Figure 22 MINOS+ has the potential to rule out much of theLSND allowed region MINOS+ will begin taking data in thelate summer of 2013 and will continue taking data for at leasttwo years (Figure 22 assumes two years of data taking with aneutrino-dominated beam)
8 Conclusion
The MINOS experiment was conceived at a time when neu-trino oscillation had only recently been confirmed as thesolution to the problem of neutrino flavour change It has
Advances in High Energy Physics 15
Δm
2
10minus210minus2
10minus1
10minus1
10minus310minus4 1
1
10
102
LSND 90 CLLSND 99 CLKarmen2 90 CLBugey 90 CLlowast
MiniBooNE 90 CLMiniBooNE 99 CLMINOS+ and Bugeycombination 90 CL
sin22120579120583e
lowastGLoBES 2012 fit with new reactor fluxescourtesy of P Huber
Figure 22 The sensitivity of MINOS+ to the existence of sterileneutrinos when combined with data from the Bugey [85] reactorneutrino experiment Δ1198982 is the splitting between the three knownneutrino mass states and a new fourth state 120579
120583119890is the mixing angle
governing ]120583rarr ]119890transitions when a fourth sterile neutrino state
is introduced into the PMNSmixingmatrixThis figure assumes twoyears of MINOS+ running with a neutrino-dominated beam
played a hugely influential role in bringing neutrino oscilla-tion physics into an era of precision measurement MINOSrsquosmeasurement of the largest neutrino mass splitting is themost precise in the world MINOS has made the first directprecision measurement of the corresponding antineutrinoparameters a measurement that promises to remain theworldrsquos most precise for many years And MINOS has playeda role in the discovery of a nonzero value for 120579
13
Now that the value of 12057913is known the neutrino physics
community can move on to determine the neutrino masshierarchy and to search for CP violation in the neutrinosector MINOS has pioneered a number of techniques thatwill be used by future experiments The two-detector setupall important in reducing the impact of systematic uncer-tainties is the design of choice for any new experiment andMINOS has demonstrated methods of using a near detectorto determine the expectation at a far detector MINOS hasperformed the first search for ]
119890appearance in a ]
120583beam
and the first search for ]119890and ]119890appearance with significant
matter effects demonstrating the analysis techniques that willbe used to determine the mass hierarchy and CP violationparameter
In the second half of 2013 MINOS will begin taking dataas the MINOS+ experiment which will make ever more pre-cise tests of the three-flavour neutrino oscillation paradigmand set world-leading limits on the existence of sterileneutrinos This is an exciting future for an experiment thatwith a decade of data taking so far has already created alasting legacy for itself in our understanding of the neutrino
A comparison of themeasured neutrino and antineutrinomass splittings is shown in Figure 14 the difference betweenthe two is constrained to |Δ119898
2| minus |Δ119898
2| = (012
+024
minus026) times
10minus3 eV2
Acknowledgment
The work of the MINOS and MINOS+ collaborations issupported by the US DoE the UK STFC the US NSF theState and University of Minnesota the University of Athensin Greece and Brazilrsquos FAPESP and CNPq The authors aregrateful to the Minnesota Department of Natural Resourcesthe crew of the Soudan Underground Laboratory and thepersonnel of Fermilab for their vital contributions
References
[1] S Wojcicki ldquoLong baseline neutrino oscillation programe inthe United Statesrdquo Nuclear Physics B vol 77 no 1ndash3 pp 182ndash186 1999 Proceedings of the 18th International Conference onNeutrino Physics and Astrophysics (Neutrino rsquo98) TakayamaJapan June 1998
[2] R Davis Jr D S Harmer and K C Hoffman ldquoSearch forneutrinos from the sunrdquo Physical Review Letters vol 20 no 21pp 1205ndash1209 1968
[3] A I Abazov O L Anosov E L Faizov et al ldquoSearch forneutrinos from sun using the reactionGa-71 (electron-neutrinoe-) Ge-71rdquo Physical Review Letters vol 67 pp 3332ndash3335 1991
[4] P Anselmann W Hampel G Heusser et al ldquoSolar neutrinosobserved by GALLEX at gran sassordquo Physics Letters B vol 285no 4 pp 376ndash389 1992
[5] M Aglietta G Battistoni E Bellotti et al ldquoExperimentalstudy of atmospheric neutrino flux in the NUSEX experimentrdquoEurophysics Letters vol 8 no 7 article 611 1989
[6] K S Hirata ldquoObservation of a small atmospheric V120583V119890ratio in
Kamiokanderdquo Physics Letters B vol 280 no 1-2 pp 146ndash1521992
[7] R Becker-Szendy C B Bratton D Casper et al ldquoElectron-and muon-neutrino content of the atmospheric fluxrdquo PhysicalReview D vol 46 pp 3720ndash3724 1992
[8] K Daum W Rhode P Bareyre et al ldquoDetermination ofthe atmospheric neutrino spectra with the frejus detectorrdquoZeitschrift fur Physik C vol 66 no 3 pp 417ndash428 1995
[9] S Ahlen M Ambrosio R Antolini and G Auriemma ldquoAtmo-spheric neutrino flux measurement using upgoing muonsrdquoPhysics Letters B vol 357 no 3 pp 481ndash486 1995
[10] WMAllison G J Alner D S Ayres et al ldquoMeasurement of theatmospheric neutrino flavour composition in Soudan 2rdquoPhysicsLetters B vol 391 no 3-4 pp 491ndash500 1997
16 Advances in High Energy Physics
[11] Y Fukuda T Hayakawa E Ichihara et al ldquoEvidence foroscillation of atmospheric neutrinosrdquo Physical Review Lettersvol 81 no 8 pp 1562ndash1567 1998
[12] Q R Ahmad R C Allen T C Andersen et al ldquoMeasurementof charged current interactions produced by solar neutrinos atthe sudbury neutrino observatoryrdquo Physical Review Letters vol87 Article ID 071301 2001
[13] Q R Ahmad R C Allen T C Andersen et al ldquoDirect evidencefor neutrino flavor transformation from neutral-current inter-actions in the sudbury neutrino observatoryrdquo Physical ReviewLetters vol 89 Article ID 011301 6 pages 2002
[14] B Pontecorvo ldquoInverse beta processes and nonconservation oflepton chargerdquo Journal of Experimental and Theoretical Physicsvol 34 pp 172ndash173 1958
[15] V N Gribov and B Pontecorvo ldquoNeutrino astronomy andlepton chargerdquo Physics Letters B vol 28 pp 493ndash496 1969
[16] Z Maki M Nakagawa and S Sakata ldquoRemarks on the unifiedmodel of elementary particlesrdquo Progress of Theoretical Physicsvol 28 no 5 pp 870ndash880 1962
[17] P Adamson C Andreopoulos D J Auty et al ldquoFirst directobservation of muon antineutrino disappearancerdquo PhysicalReview Letters vol 107 no 2 Article ID 021801 2011
[18] P Adamson D J Auty D S Ayres et al ldquoSearch for thedisappearance of muon antineutrinos in the NuMI neutrinobeamrdquo Physical Review D vol 84 no 7 Article ID 071103 6pages 2011
[19] P Adamson D S Ayres C Backhouse et al ldquoImprovedmeasurement of muon antineutrino disappearance inMINOSrdquoPhysical Review Letters vol 108 no 19 Article ID 191801 5pages 2012
[20] P Adamson I Anghel C Backhouse et al ldquoMeasurementof Neutrino and Antineutrino Oscillations Using Beam andAtmospheric Data in MINOSrdquo Physical Review Letters vol 110no 25 Article ID 251801 6 pages 2013
[21] K Anderson B Bernstein D Boehnlein et al ldquoThe NuMIFacility Technical Design Reportrdquo FERMILAB-DESIGN-1998-01 1998
[22] D G Michael P Adamson T Alexopoulos et al ldquoObservationof muon neutrino disappearance with the MINOS detectors inthe NuMI neutrino beamrdquo Physical Review Letters vol 97 no19 Article ID 191801 6 pages 2006
[23] P Adamson C Andreopoulos K E Arms et al ldquoStudy ofmuon neutrino disappearance using the fermilab main injectorneutrino beamrdquo Physical Review D vol 77 no 7 Article ID072002 34 pages 2008
[24] P Adamson C Andreopoulos K E Arms et al ldquoMeasurementof neutrino oscillations with theMINOS detectors in the NuMIbeamrdquo Physical Review Letters vol 101 no 13 Article ID 1318025 pages 2008
[25] P Adamson C Andreopoulos R Armstrong et al ldquoMea-surement of the neutrino mass splitting and flavor mixing byMINOSrdquo Physical Review Letters vol 106 no 18 Article ID181801 6 pages 2011
[26] P Adamson C Andreopoulos K E Arms et al ldquoSearch formuon-neutrino to electron-neutrino transitions in MINOSrdquoPhysical Review Letters vol 103 no 26 Article ID 261802 5pages 2009
[27] PAdamsonCAndreopoulosD J Auty et al ldquoNew constraintsonmuon-neutrino to electron-neutrino transitions inMINOSrdquoPhysical ReviewD vol 82 no 5 Article ID 051102 6 pages 2010
[28] P Adamson D J Auty D S Ayres et al ldquoImproved search formuon-neutrino to electron-neutrino oscillations in MINOSrdquoPhysical Review Letters vol 107 no 18 Article ID 181802 6pages 2011
[29] P Adamson I Anghel C Backhouse et al ldquoElectron neutrinoand antineutrino appearance in the full MINOS data samplerdquoPhysical Review Letters vol 110 no 17 Article ID 171801 6 pages2013
[30] P Adamson C Andreopoulos K E Arms et al ldquoSearch foractive neutrino disappearance using neutral-current interac-tions in theMINOS long-baseline experimentrdquo Physical ReviewLetters vol 101 no 22 Article ID 221804 5 pages 2008
[31] P Adamson C Andreopoulos D J Auty et al ldquoSearch for ster-ile neutrino mixing in the MINOS long-baseline experimentrdquoPhysical Review D vol 81 no 5 Article ID 052004 18 pages2010
[32] P Adamson D J Auty D S Ayres et al ldquoActive to sterileneutrino mixing limits from neutral-current interactions inMINOSrdquo Physical Review Letters vol 107 no 1 Article ID011802 5 pages 2011
[33] Z Pavlovic Observation of disappearance of muon neutrinos inthe NuMI beam [PhD thesis] University of Texas at AustinAustin Tex USA 2008
[34] F Ballarini G Battistoni M Campanella et al ldquoThe FLUKAcode an overviewrdquo Journal of Physics vol 41 article 151 2006
[35] S Agostinelli J Allison K Amako et al ldquoGEANT4mdasha sim-ulation toolkitrdquo Nuclear Instruments and Methods in PhysicsResearch A vol 506 no 3 pp 250ndash303 2003
[36] G Battistoni F Cerutti A Fasso et al ldquoThe FLUKA codedescription and benchmarkingrdquo in Proceedings of the HadronicShower Simulation Workshop vol 896 of AIP Conference Pro-ceedings pp 31ndash49 Batavia Ill USA September 2006
[37] D G Michaele P Adamson T Alexopoulos et al ldquoThe mag-netized steel and scintillator calorimeters of the MINOS exper-imentrdquoNuclear Instruments and Methods in Physics Research Avol 596 no 2 pp 190ndash228 2008
[38] I E Stockdale A Bodek F Borcherding N Giokaris et alldquoLimits on muon-neutrino oscillations in the mass range 30 lt9987791198982lt 1000 eV2c4 rdquo Physical Review Letters vol 52 no 16 pp
1384ndash1388 1984[39] F Dydak G J Feldman C Guyot et al ldquoA search for V
120583
oscillations in the9987791198982 range 03ndash90 eV2 rdquo Physics Letters B vol134 no 3-4 pp 281ndash286 1984
[40] F Bergsma J Dorenbosch M Jonker et al ldquoA searchfor oscillations of muon neutrinos in an experiment withLEcong07 kmGeVrdquo Physics Letters B vol 142 no 1-2 pp 103ndash1101984
[41] M H Ahn E Aliu S Andringa et al ldquoMeasurement ofneutrino oscillation by the K2K experimentrdquo Physical ReviewD vol 74 no 7 Article ID 072003 39 pages 2006
[42] P Adamson T Alexopoulos W W M Allison et al ldquoFirstobservations of separated atmospheric V
120583and ]
120583events in the
MINOS detectorrdquo Physical Review D vol 73 no 7 Article ID072002 2006
[43] P Adamson C Andreopoulos K E Arms et al ldquoCharge-separated atmospheric neutrino-inducedmuons in theMINOSfar detectorrdquo Physical ReviewD vol 75 no 9 Article ID 09200314 pages 2007
[44] P Adamson C Backhouse G Barr et al ldquoMeasurements ofatmospheric neutrinos and antineutrinos in the MINOS fardetectorrdquo Physical Review D vol 86 no 5 Article ID 05200720 pages 2012
Advances in High Energy Physics 17
[45] M A Kordosky Hadronic interactions in the MINOS detectors[PhD thesis] University of Texas at Austin Austin Tex USA2004
[46] P L Vahle Electromagnetic interactions in the MINOS detectors[PhD thesis] University of Texas at Austin Austin Tex USA2004
[47] C Backhouse Measuring neutrino oscillation parameters using]120583disappearance inMINOS [PhD thesis] University of Oxford
Oxford UK 2011[48] T M Cover and P E Hart ldquoNearest neighbor pattern classifi-
cationrdquo IEEE Transactions on Information Theory vol 13 no 1pp 21ndash27 1967
[49] R Ospanov A measurement of muon neutrino disappearancewith the MINOS detectors and NuMI beam [PhD thesis]University of Texas at Austin Austin Tex USA 2008
[50] J S Marshall A study of muon neutrino disappearance with theMINOS detectors and the NuMI neutrino beam [PhD thesis]University of Cambridge Cambridge UK 2008
[51] J P OchoaA search formuon neutrino to electron neutrino oscil-lations in the MINOS Experiment [PhD thesis] The CaliforniaInstitute of Technology Pasadena Calif USA 2009
[52] R TonerMeasuring 12057913via muon neutrino to electron neutrino
oscillations in the MINOS experiment [PhD thesis] Universityof Cambridge Cambridge UK 2011
[53] A Holin Electron neutrino appearance in the MINOS experi-ment [PhD thesis] University College London London UK2010
[54] J Boehm Measurement of electron neutrino appearance withthe MINOS experiment [PhD thesis] Harvard UniversityCambridge Mass USA 2009
[55] G Tinti Sterile neutrino oscillations in MINOS and hadronproduction in pC collisions [PhD thesis] University of OxfordOxford UK 2010
[56] J J EvansMeasuring antineutrino oscillations with the MINOSexperiment [PhD thesis] University of Oxford Oxford UK2008
[57] S J ColemanAmeasurement of neutrino oscillations withmuonneutrinos in the MINOS experiment [PhD thesis] College ofWilliam ampMary Williamsburg Va USA 2011
[58] J S Mitchell Measuring ]120583disappearance with the MINOS
experiment [PhD thesis] University of Cambridge CambridgeUK 2011
[59] A McGowan Observation of deficit in NuMI neutrino-inducedrock and non-fiducial muons in MINOS far detector andmeasurement of neutrino oscillation parameters [PhD thesis]University of Minnesota Minneapolis Minn USA 2007
[60] M StraitMeasurement of neutrino oscillation parameters usinganti-fiducial charged current events in MINOS [PhD thesis]University of Minnesota Minneapolis Minn USA 2010
[61] Y Itow ldquoAtmospheric neutrinosmdashresults from running exper-imentsrdquo in Proceedings of the 25th International Conference onNeutrino Physics and Astrophysics (Neutrino rsquo12) Kyoto JapanJune 2012
[62] K Abe N Abgrall Y Ajima et al ldquoFirst muon-neutrinodisappearance study with an off-axis beamrdquo Physical Review Dvol 85 no 3 Article ID 031103 8 pages 2012
[63] K Nakamura ldquoReview of particle physicsrdquo Journal of Physics Gvol 37 Article ID 075021 2010
[64] L Wolfenstein ldquoNeutrino oscillations in matterrdquo PhysicalReview D vol 17 no 9 pp 2369ndash2374 1978
[65] J W F Valle ldquoResonant oscillations of massless neutrinos inmatterrdquo Physics Letters B vol 199 no 3 pp 432ndash436 1987
[66] M C Gonzalez-Garcia M M Guzzo P I Krastev et alldquoAtmospheric neutrino observations and flavor changing inter-actionsrdquo Physical Review Letters vol 82 no 16 pp 3202ndash32051999
[67] A Friedland C Lunardini and M Maltoni ldquoAtmosphericneutrinos as probes of neutrino-matter interactionsrdquo PhysicalReview D vol 70 no 11 Article ID 111301 2004
[68] Z IsvanAntineutrino oscillations and a Search for non-standardInteractions with the MINOS [PhD thesis] University of Pitts-burgh Pittsburgh Pa USA 2012
[69] W A Mann D Cherdack W Musial and T Kafka ldquoApparentmultiple 998779119898
32
2 in ]120583and V
120583survival oscillations from nonstan-
dard interactionmatter effectrdquo Physical Review D vol 82 no 11Article ID 113010 8 pages 2010
[70] J Kopp P A N Machado and S J Parke ldquoInterpretation ofMINOS data in terms of nonstandard neutrino interactionsrdquoPhysical Review D vol 82 no 11 Article ID 113002 12 pages2010
[71] J A B Coelho Investigacao de mecanismos alternativos aoscilacao de neutrinos no experimentos MINOS [PhD thesis]Universidade Estadual de Campinas Sao Paulo Brazil 2012
[72] F P An Q An J Z Bai A B Balantekin et al ldquoImprovedmeasurement of electron antineutrino disappearance at DayaBayrdquo Chinese Physics C vol 37 Article ID 011001 21 pages 2013
[73] J K Ahn S Chebotaryov J H Choi et al ldquoObservationof reactor electron antineutrinos disappearance in the RENOexperimentrdquo Physical Review Letters vol 108 Article ID 1918026 pages 2012
[74] Y Abe C Aberle J C dos Anjos et al ldquoReactor electronantineutrino disappearance in the Double Chooz experimentrdquoPhysical Review D vol 86 Article ID 052008 2012
[75] K Abe N Abgrall H Aihara et al ldquoEvidence of electronneutrino appearance in a muon neutrino beamrdquo PhysicalReview D vol 88 no 3 Article ID 032002 41 pages 2013
[76] A Schreckenberger Electron neutrino and antineutrino appear-ance in the MINOS detector [PhD thesis] University of Min-nesota Minneapolis Minn USA 2013
[77] D J Koskinen MINOS sterile neutrino search [PhD thesis]University College London London UK 2009
[78] M Apollonio A Baldini C Bemporad et al ldquoSearch forneutrino oscillations on a long base-line at the CHOOZ nuclearpower stationrdquoTheEuropean Physical Journal C vol 27 pp 331ndash374 2003
[79] G Tzanankos M Bishai M Diwan et alMINOS+ a proposalto FNAL to run MINOS with the medium energy NuMI beam[PhD thesis] University of Athens Athens Greece 2011
[80] A Aguilar L B Auerbach R L Burman et al ldquoEvidence forneutrino oscillations from the observation of ]
119890e appearance
in a ]120583beamrdquo Physical Review D vol 64 Article ID 112007 22
pages 2001[81] A A Aguilar-Arevalo C E Anderson S J Brice et al ldquoSearch
for electron antineutrino appearance at the Δ119898 sim 1 eV2 ScalerdquoPhysical Review Letters vol 103 no 11 Article ID 111801 2009
[82] A A Aguilar-Arevalo C E Anderson A O Bazarko et alldquoImproved search for V
120583rarr V119890oscillations in the MiniBooNE
experimentrdquo Physical Review Letter vol 110 no 10 Article ID161801 2013
[83] GMentionM Fechner T Lasserre et al ldquoReactor antineutrinoanomalyrdquo Physical Review D vol 83 Article ID 073006 20pages 2011
18 Advances in High Energy Physics
[84] KNAbazajianMAAcero S KAgarwalla et al ldquoLight sterileneutrinos a white paperrdquo httparxivorgabs12045379
[85] B Achkar R Aleksan M Avenier et al ldquoSearch for neutrinooscillations at 15 40 and 95meters from a nuclear power reactorat Bugeyrdquo Nuclear Physics B vol 434 no 3 pp 503ndash532 1995
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Superconductivity
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ThermodynamicsJournal of
2 Advances in High Energy Physics
Target hall Evacuated pipeTarget
Protons frommain injector
10m 30m 675m5m
12m 18m
Rock
Beam stop
Pion (120587+
120587+
120587+
)Muon (120583+)
Muon monitors
120583+
120583+
300mHadron (pion) monitor
Horn 1 Horn 2120592
120592
120592
Figure 1 The NuMI beam
2 The MINOS Experiment
The NuMI facility [21] provides MINOS with an intensebeam of muon flavoured neutrinos at energies of a few GeVThe atmospheric neutrino mass splitting drives oscillationpredominantly between muon and tau flavour neutrinos theenergy dependence of themuonneutrino survival probabilityis given by
119875 (]120583997888rarr ]120583)
= 1 minus sin2 (2120579) sin2(127Δ119898
2[eV2] 119871 [km]
119864 [GeV])
(1)
In this two-flavour approximation Δ1198982 is an admixture ofΔ1198982
32and Δ1198982
31 120579 is also an admixture of the mixing angles
but is heavily dominated by 12057923 SinceMINOS cannot observe
the ]120591appearance it is the measurement of this ]
120583survival
probability that is used to determine the parameters 120579 andΔ1198982 [20 22ndash25]A nonzero 120579
13causes a small amount of ]
119890appearance in
the beam with an energy dependence given by
119875 (]120583997888rarr ]119890)
asymp sin2 (12057923) sin2 (2120579
13) sin2(
127Δ1198982[eV2] 119871 [km]
119864 [GeV])
(2)
MINOS has selected a sample of ]119890-enhanced events to make
a measurement of 12057913[26ndash29]
An important signature of neutrino oscillation is thatthe rate of neutral-current (NC) neutrino interactions isunchanged by the process The NC interaction is equallysensitive to all three neutrino flavours so this proves thatflavour change is occurring between the three active neutrinoflavours By analysing NC interactions MINOS has con-firmed that oscillation is the correct picture and has shownno evidence that this oscillation includes additional sterileneutrino flavours [30ndash32]
The NuMI beam [21] based at Fermilab in Chicagohas run since 2005 and has reached a typical beam powerof 350 kW The Fermilab main injector produces a 10 120583spulse of around 3 times 1013 protons every 22 s These protonshave an energy of 120GeV and strike a graphite target as
shown in Figure 1 This target has a length of 20 nuclearinteraction lengths and consists of a series of forty-seven2 cm long graphite fins separated by 03mm A shower ofhadrons is produced at the target consisting primarily ofpions with a significant kaon component at higher energiesThese hadrons pass through two parabolic magnetic hornswhich focus either positive or negative hadrons depending onthe direction of the electric current through the horns Thefocused hadrons pass down a 675m long helium filled pipein which they decay to produce a beam of predominantlymuon flavoured neutrinos with a small electron neutrinocomponent from the decays of muons and kaons
Figure 2 shows the composition of the NuMI beamWith the horns configured to focus positive hadrons thespectrum of charged current (CC) interactions observed inthe MINOS near detector at Fermilab consists of 917 ]
120583
70 ]120583 and 13 ]
119890and ]119890 With the horns focusing negative
hadrons the observed CC interactions consist of 399 ]120583
581 ]120583 and 20 ]
119890and ]
119890 The significant difference in
composition and event rate between these two configurationsarises mainly from the fact that the ]
120583interaction cross-
section is approximately a factor of two lower than the ]120583
interaction cross-sectionThe neutrino beam peaks at an energy of close to 3GeV
However the current through the focusing horns and therelative positions of the horns and target are variable allowingthe energy of the beam peak to be varied to as high as 10GeVThis feature has enabledMINOS to study and understand thebeam in detail [33] improving the simulation of the beambeyond the raw Fluka [34] andGEANT [35 36]Monte Carlosand significantly reducing the systematic uncertainty fromthe modeling of the neutrino flux
A total of 1056 times 1020 protons on target of beam data
has been analysed in the neutrino-dominated beam modeThis data corresponds to the beam configuration shown inFigure 2 with the energy spectrum peaking at 3GeV and isreferred to as the low energy beam configuration Additional015times10
20 protons on target of data with a 10GeV beam peakhave also been used In the antineutrino-enhanced beammode a total of 336times1020 protons on target of beamdata havebeen analysed These are the exposures used for all analysespresented in this paper except where otherwise stated andthey were obtained between May 2005 and April 2012
The two MINOS detectors [37] are steel-scintillatorcalorimeters shown in Figure 3 They consist of planes of
Advances in High Energy Physics 3
Neutrino-dominated
True energy (GeV)5 10 15 20 25 300
0
02
04
06
08
1
Near detector simulated Low energy beam
Flux
times120590
CC
(au
)
120583 spectrum120583 spectrum
(a)
True energy (GeV)5 10 15 20 25 300
0
02
04
06
08
1
Near detector simulatedLow energy beam
Antineutrino-enhanced
Flux
times120590
CC
(au
)
120583 spectrum120583 spectrum
(b)
Figure 2The composition of theNuMIbeamwhen configured to produce (a) a neutrino-dominated beamand (b) an antineutrino-enhancedbeam The figures show the rate of charged current neutrino interactions observed in the MINOS near detector
(a) (b)
Figure 3 The MINOS detectors (a) the near detector at Fermilab (b) the far detector at the Soudan Underground Laboratory
inch-thick steel interleaved with planes of 1 cm thick plasticscintillator The scintillator planes are divided into 4 cm widestrips as shown in Figure 4 Along the centre of each strip awavelength shifting fibre collects the scintillation light shiftsit to green wavelengths and takes it out to a photomultipliertube Any charged particles passing through the detectordeposit their energy to produce light the pattern of thesedeposits allows the topology of the neutrino interaction to bereconstructedThe scintillator strips are aligned orthogonallyon adjacent detector planes to allow three-dimensionalreconstructionThe detectors are magnetised to around 13 Tallowing the charge of particles to be identified
The smaller of the two detectors the Near Detector(ND) sits at Fermilab 104 km from the target With amass of 098 kton it measures the energy spectra of theneutrinos before oscillation The far detector is located atthe SoudanUndergroundLaboratory in northernMinnesota705m underground and 735 km from the target With a massof 54 kton it again measures the neutrino energy spectra
seeing the appearance and disappearance of neutrinos due tooscillation
This two-detector arrangement previously used overdistances of around 1 km by experiments such as CCFRCDHS and CHARM [38ndash40] and then over 250 km by K2K[41] is very powerful in reducing systematic uncertaintiesNeutrino physics is beset with uncertainty in particularinteraction cross-sections are unknown to many tens of percent and neutrino fluxes can be mismodeled by similaramounts However these uncertainties affect both the nearand far detectors in very similar ways Thus when a ratio istaken of the energy spectra measured in the two detectorsa cancellation occurs and the effects of the uncertainties aregreatly reduced As an indication of how well this worksdespite the uncertainties of tens of per cent in the simulatedevent rate in the detectors once the near to far detector ratiois taken the normalization is known to 16 this 16 isdominated by the uncertainty in the relative efficiency of theevent reconstruction algorithms between the two detectors
4 Advances in High Energy Physics
PMT assembly
CookieMUX box optical
connectorOptical cable
MUX box
Optical connector
WLS fibers
Scintillator strips
Steel plates
Figure 4 A MINOS detector plane
The MINOS Far Detector is also a very effective detectorof neutrinos produced in the atmosphere Since it wasswitched on in 2003 it has recorded 379 kton-years of datarecording 2072 candidate neutrino interactions that havebeen included into the analyses of the beam data to improvethe precision of the oscillation parameter measurements [2042ndash44]
3 Neutrino Interactions inthe MINOS Detectors
Three types of neutrino interaction shown in Figure 5 areof interest to MINOS Muon neutrinos and antineutrinosinteract through the CC process
]120583(]120583) + 119883 997888rarr 120583
minus(+)+ 1198831015840 (3)
The cascade of hadrons 1198831015840 produces a diffuse shower ofenergy deposits near the interaction vertex The muon pro-duces a long track that curves in the magnetic field thedirection of curvature identifying the incoming neutrino asa ]120583or a ]120583
All active neutrino flavours undergo NC interactionsthrough the process
] + 119883 997888rarr ] + 1198831015840 (4)
Only the hadronic cascade is observed producing a diffuseshower of energy deposits
Finally electron neutrinos undergo CC interactionsthrough the process
]119890+ 119883 997888rarr 119890
minus+ 1198831015840 (5)
The electron gives rise to an electromagnetic shower whichproduces a much denser more compact shower of energydeposits
The energy of the neutrino is determined by summing theenergies of the shower and anymuon trackThemuon energyis determined from the length of stopping tracks leading toa resolution of around 5 and from the curvature in themagnetic field for tracks that exit the detector leading to aresolution of around 10 For NC and ]
119890CC interactions
the energy of the shower is determined through calorimetryThe calorimetric energy resolution for hadronic showers isaround 55radicenergy [45] and for electromagnetic showers20radicenergy [46] For ]120583 CC interactions a more sophisti-cated approach is used to improve the resolution of hadronicshower energy measurement [47] For low energy showers(of a few GeV or below) significant additional information isheld in the topology of the showerThree event characteristicsare used the calorimetric energy deposit within 1m of theinteraction vertex the sum of the calorimetric energy in thetwo largest showers in the event and the physical length ofthe largest shower These variables are input into a 119896-nearest-neighbour algorithm [48] which finds the best matches froma library of simulated events and uses these to estimate thehadronic energyThis improves the shower energy resolutionfrom 55 to 43 for showers between 10GeV and 15 GeV
31 Selection of Charged-Current ]120583and ]
120583Interactions To
make a measurement of 119875(]120583
rarr ]120583) it is necessary to
select a pure sample of ]120583CC interactions This is achieved
by selecting events with a clear muon track The main loss inefficiency comes from events with a high inelasticity in whicha short muon track is hidden in a large hadronic cascade
Advances in High Energy Physics 5
CC 120583 event
120583minus
15
1
05
0
0
05 1 15 2 25 3 35 4
Longitudinal position (m)
Tran
sver
se p
ositi
on (m
)
minus05
(a)
V
06
04
02
0
minus02
minus02
minus04
minus04
minus06
0 02 04 06 08 1
NC event
Longitudinal position (m)
Tran
sver
se p
ositi
on (m
)
(b)
e
02
0
02
0 05 1
CC e event
Longitudinal position (m)
Tran
sver
se p
ositi
on (m
)
lowast
(c)
Figure 5 Neutrino interaction topologies observed in the MINOS detectors (a) A CC ]120583interaction (b) A NC interaction (c) A CC ]
119890
interaction Each coloured rectangle represents an excited scintillator strip the colour indicating the amount of light purple and blue are lowlight levels through to orange and red for the highest light levels
The main background occurs at low energies and consists ofsmall cascades from NC interactions in which a low energyhadron such as a proton or a charged pion exhibits a track-like topology that mimics a low energy muon Four variablesare constructed that discriminate between muons trackswhich are typically long and show a constant energy deposi-tion along the length and spurious hadronic tracks which aretypically shorter and show greater fluctuations in the energydeposition These variables are the event length the averageenergy deposited per scintillator plane along the track thetransverse energy deposition profile and the fluctuation of
the energy deposition along the track These variables areinput into a 119896-nearest-neighbour algorithm which calculatesa single discrimination variable shown in Figure 6 [49]Events for which this variable is greater than 03 are selectedas CC ]
120583interactions yielding a sample with a total efficiency
of 90 below 2GeV the NC contamination is 65 Theefficiency and contamination are energy dependent this fullenergy dependence is shown in Figure 6
The CC interactions of ]120583and ]
120583result in very similar
topologies the 119896-nearest-neighbour discriminant is thereforeused in the same way in both the neutrino-dominated and
6 Advances in High Energy Physics
CCNC separation parameter
Low energy beamDataMC expectation
NC background
Even
ts10
16PO
T
10
1
10minus1
10minus2
0 02 04 06 08 1
(a)
Reconstructed neutrino energy (GeV)
0
02
04
06
08
1
NC contamination
Far detector fiducial onlyCC selection efficiency
0 2 4 6 8 10
Effici
ency
con
tam
inat
ion
(b)
Figure 6 (a) The discrimination variable used to separate ]120583CC interactions from hadronic backgrounds Events with a parameter value
greater than 03 are selected as ]120583CC interactions (b) The efficiency and background contamination of the selected ]
120583CC sample in the far
detector
antineutrino-enhanced beams When performing a directmeasurement of the antineutrino oscillation parameters anadditional selection cut is made requiring the charge of themuon track to be positiveThis uses the direction of curvatureof themuon asmeasured by aKalman Filter algorithm [50] Afurther sample of ]
120583CC interactions is obtained from the 7
]120583component in the neutrino-dominated beamThis sample
contains a significant background of ]120583events in which a 120583minus
has been identified with the incorrect charge often at lowenergies where the muon undergoes significant scatteringTherefore a much stricter set of selection criteria are appliedto purify this ]
120583sample [18]
32 Selection of Charged-Current ]119890Interactions The selec-
tion of ]119890CC interactions focuses on identifying the dense
showers from the electromagnetic interaction of the electronrather than the much more diffuse hadronic showers Theprimary background comes from purely hadronic showerswhich can have a denser than average energy depositparticularly in the presence of a neutral pion decaying tophotons Once a set of shower-like events in the signalregion of 1ndash8GeV has been obtained a pattern matchingapproach called library event matching is used to identifythe interactions most likely to be ]
119890CC [51 52] Each event
in the data is compared to a library of 5 times 107 simulated
signal and background events its similarity to the libraryevents is quantified by comparing the pattern of energydeposits in each scintillator strip excited by the shower wherethe energy deposit is quantified by the charge recorded onthe photomultiplier tube For an arbitrary energy depositthe mean expected charge on a photomultiplier tube willbe some value 120582 The probability of observing an amountof charge 119899 is then a Poisson distribution 119875(119899 | 120582) Thelikelihood L of a data event corresponding to the same
physical shower topology as a simulated library event cantherefore be calculated as
logL =
119873strips
sum
119894=1
log [intinfin
0
119875 (119899119894
data | 120582) 119875 (119899119894
lib | 120582) d120582] (6)
where 119894 represents the 119894th scintillator strip in the showerUsing this definition of the likelihood the 50 library eventsare identified that best match the data eventThree quantitiesare calculated from this set of 50 best-matching library eventsthe fraction of the events that are true ]
119890CC events the
average inelasticity of the true ]119890CC events and the average
fraction of charge that overlaps between the data event andeach ]
119890CC library event These three quantities are input to
a neural network which calculates a classification variableshown in Figure 7 Events with a classification variable valueabove 06 are selected for analysis this value was chosen tomaximise the sensitivity to ]
119890and ]119890appearance
The efficiency of the ]119890CC selection is estimated from
the data rather than relying totally on the simulation Toobtain a pure sample of true hadronic showers a sampleof well-identified ]
120583CC events is selected and the energy
depositions corresponding to the muon track are removed[53]The simulated energy depositions of an electron are theninserted [54] providing a realistic sample of ]
119890CC events
Using thismethod the ]119890CC identification efficiency is found
to be (574 plusmn 28) in the neutrino-dominated beam and(633 plusmn 31) in the antineutrino-enhanced beam
33 Selection of Neutral-Current Interactions The signal of anNC interaction is a diffuse hadronic shower ]
120583CC interac-
tions also produce hadronic showers and if the inelasticityis high the tell-tale muon track may not visibly extend pastthe shower To purify a sample of NC interactions a simple
Advances in High Energy Physics 7
sin2(212057913) = 01
Δm232 gt 0 120575cp = 0 12057923 =
120587
4
Background
MINOS far detector80
60
40
20
00 01 02 03 04 05 06 07 08 09 1
LEM discriminant
Signal times10
Even
ts8
2times10
20PO
T
(a)
LEM discriminant
Even
ts10
19PO
T
DataMonte Carlo
MINOS near detector8000
6000
4000
2000
00 01 02 03 04 05 06 07 08 09 1
(b)
Figure 7 (a) The library event matching discriminant showing the expected distribution for background and CC ]119890signal events in the far
detector in the neutrino-dominated beam Note that the signal simulated for sin2(212057913) = 01 120575 = 0 and a normal mass hierarchy has been
scaled up by a factor of ten for visibility (b)The same discriminant as observed in the near detector compared with the simulated expectation
Near detector dataMonte Carlo prediction
20
10
30
50
2018161410 120
0 2 4 6 8
40
60
120583 CC background
Ereco (GeV)
104
even
ts (G
eV)
Figure 8 The sample of events identified as NC interactions in thenear detector
cut-based approach is taken [55] events are classified asNC-like if the event contains no reconstructed track or ifthe track extends no more than six planes past the end ofthe shower The resulting distribution of NC interactions inthe near detector is shown in Figure 8 The NC identificationefficiency is 89 with 61 purity This selection will identify97 of ]
119890CC interactions as NC events therefore an analysis
of NC interactions in the FD must account for the ]119890
appearance caused by a nonzero 12057913
34 Selection of Atmospheric Neutrinos Atmospheric neu-trino interactions are selected out of any activity seen in
the FD outside of the 10 120583s periods when the NuMI beamis active [44] The oscillation signal is contained in the ]
120583
CC interactions and as with the beam-induced interactionsthese are identified by the presence of a muon track The FDbegan taking data with atmospheric neutrinos in July 2003two years before the NuMI beam began running
The FD has a single-hit timing resolution of 25 ns Thistiming information is used to determine the direction inwhich the detector activity is traveling Any downwardstraveling activity is required to begin well inside the detec-tor to eliminate cosmic muons entering from above Allupwards or horizontally traveling activity is almost certainto be neutrino-induced since no other particle can survivethrough the many kilometres of rock All activity with azenith angle of cos 120579
119911lt 014 is defined as horizontal or down-
going this corresponds to an overburden of at least 14 kmwater equivalent
From this sample of neutrino-induced activity all eventswith a track crossing at least eight planes are designatedtrack-like all events with only shower-like activity crossing atleast four planes are designated shower-like These track-likeand shower-like samples are used in the neutrino oscillationmeasurementsThe track-like sample contains the oscillationsignal of ]
120583disappearance The shower-like sample contains
mainly NC interactions and ]119890and ]
119890CC interactions it
shows little oscillation signal but is very important for settingthe normalization of the atmospheric neutrino flux
4 Muon Neutrino andAntineutrino Disappearance
The atmospheric oscillation parameters |Δ1198982| and sin2(2120579)aremeasured by observing and fitting the energy dependenceof ]120583and ]
120583disappearance To minimise the impact of
8 Advances in High Energy Physics
20
40
60
80
100
120
0 10 15 20 30 50
Even
tstimes10
4(G
eV)
MINOS near detector dataMCMC uncertaintyNC background
MINOS near detectorLow energy beam 120583-mode729 times 1020 POT
Reconstructed 120583 energy (GeV)5
Figure 9 The energy spectrum of ]120583CC interactions observed in
the ND compared to the simulation
systematic uncertainties the energy spectra of the ]120583and
]120583CC interactions observed in the ND (shown in Figure 9
for the neutrino-dominated beam) are used to predict thespectrum at the FD in the absence of oscillation [23 56]The neutrino energy spectra at the ND and FD are notidentical the ND subtends a relatively large angle to thebeam so for each pion or kaon a range of decay anglescan produce a neutrino that passes through the detectorcorresponding to a range of neutrino energies However theFD is effectively a point when viewed from the neutrinoproduction location so a single decay angle for each hadrontherefore a single neutrino energy contributes to the fluxTo take this difference into account the hadron-decay kine-matics are encoded into a beam transfer matrix that convertsthe observed ND flux into a predicted FD flux Once theND data has been used in this way the most importantsystematic uncertainties are those that can affect the twodetectors differently primarily reconstruction efficienciesand miscalibrations of the neutrino energy measurementin the detectors [57] These uncertainties are included inthe fit that extracts the oscillation parameters [58] Theuncertainty on the reconstruction efficiency is modeled as a16 uncertainty on the relative rate of events between theND and FD The uncertainty on the measurement of muonenergy has two components that are fully correlated betweenthe detectors a 2 uncertainty on energies measured fromrange and a 3 uncertainty on energies measured fromthe curvature in the magnetic field The uncertainty in thehadronic energy measurements also has two componentsAn uncertainty arising from shower modeling uncertaintiesand calibration is fully correlated between the detectorsand is parameterized as (66 + 35119890119864shw14GeV) The secondcomponent is uncorrelated between the detectors and is 19
in theND and 11 in the FD this is dominated by calibrationuncertainties
The top row of Figure 10 shows the predicted spectra of]120583and ]120583CC interactions from the neutrino-dominated and
antineutrino-enhanced beams at the FD along with the dataIn the neutrino-dominated beam an additional sample isused consisting of neutrinos interacting outside the fiducialvolume of the detector and in the rock surrounding thedetector [59 60] This nonfiducial sample consists mainlyof high energy neutrinos and has significantly lower res-olution as not all the energy is contained in the detectorhowever it does contain some oscillation information Intotal 8100 reconstructed neutrino events are used in theanalysis without oscillations 9471 would be expected Inall samples a clear energy-dependent deficit of ]
120583and
]120583interactions is observed The ratio of the data to the
expectation for the ]120583interactions in the neutrino-dominated
beam is shown in Figure 11This ratio shows the ldquodip and riserdquoenergy dependence of the deficit which is characteristic ofoscillation and described by (1)
The bottom row of Figure 10 shows the spectra of atmo-spheric ]
120583and ]120583CC interactions as a function of 119871119864 where
119871 is the distance traveled by the neutrino and 119864 is its energyThe atmospheric neutrino events are divided into ]
120583and ]120583
interactions according to the direction of curvature of themuon and separated into samples depending on whether ornot the interaction vertex is contained in the detector
All the observed ]120583and ]120583CC interactions are fit accord-
ing to the two-flavour model of (1) under the assumptionthat neutrinos and antineutrinos have the same oscillationparametersThe resultingmeasurement of |Δ1198982| and sin2(2120579)is shown in Figure 12 The fit yields |Δ1198982| = (241
+009
minus010) times
10minus3 eV2 and sin2(2120579) = 0950
+0035
minus0036 disfavouring maximal
mixing at the 86 confidence level Figure 12 compares thismeasurement to those from Super-Kamiokande [61] andT2K [62] The MINOS measurement is the most precisedetermination of |Δ1198982| and all measurements of sin2(2120579) areconsistent
41 Muon Antineutrino Disappearance In the standardmodel of neutrino oscillation neutrinos and antineutrinosobey the same parameters with CPT symmetry requiringthat the masses of particles and antiparticles are identicalThe most sensitive test of this symmetry in other sectors isfrom the kaon system [63] The data from the antineutrino-enhanced beam and the interaction of atmospheric antineu-trinos enables the first direct comparison of the neutrinoand antineutrino oscillation parameters in the atmosphericregion This comparison provides a limit on nonstandardinteractions with the matter being passed through by theneutrino beam [64ndash70]
Figure 10 showed the energy spectra of ]120583interactions
observed in the FD These spectra can be fit in the two-flavour model of (1) allowing the antineutrino oscillationparameters to differ from those for neutrinos This fit yieldsthe antineutrino parametermeasurement shown in Figure 13|Δ1198982| = (250
+023
minus025) times 10
minus3 eV2 and sin2(2120579) = 097+003
minus008
This is in excellent agreement with the parameters measured
Advances in High Energy Physics 9
Neutrino energy (GeV) Neutrino energy (GeV) Neutrino energy (GeV)
0
20
40
60
80
0
5
10
10
15
1515
20
20
25
25
30
Muon energy (GeV)
0
200
400
600
800
0
100
200
300
400
500
6001071 times 1020 POT
Even
ts (G
eV)
Even
ts (G
eV)
Even
ts (G
eV)
Even
ts (G
eV)
120583 120583
120583120583
0 02 4 56 0 2 4 68 910 12 14 0 2 4 6 8 10 12 14
Neutrino beam Neutrino beam Neutrino beam Antineutrino beam
contained-vertex 120583
nonfiducial 120583contained-vertex 120583
contained-vertex 120583 336 times 1020 POT
(a)
0
20
40
60
0
10
20
30
0
10
20
30
0
5
10
15
20
25
MINOS dataBest fit oscillationsNo oscillations
NC backgroundCosmic-ray muons
120583 120583 120583 120583
0 1 2 3 4 0 1 2 3 4 0 1 2 3 4 0 1 2 3 4
Even
ts
Even
ts
Even
ts
Even
ts
Atmos contained-vertex 120583 Atmos nonfiducial 120583minus Atmos nonfiducial 120583+3788kton-years
Atmos contained-vertex 120583
log10( (km)E (GeV)) log10( (km)E120583 (GeV))L L log10( (km)E (GeV))L log10( (km)E120583 (GeV))L
(b)
Figure 10 The energy spectra of ]120583and ]
120583CC interactions observed at the FD compared to the expectation with and without oscillation
(a) shows beam-induced neutrinos (b) shows atmospheric neutrinos
with neutrinos alone (the red line in Figure 13) It should benoted that the first MINOS measurement of the antineutrinooscillation parameters released in 2010 [17] yielded a notabletension between the ] and ] oscillation parameters whichwere in agreement only at the 20 confidence levelThis ten-sion was shown to be a statistical fluctuation as the additionof further data brought the ] and ] parameters measurementsinto good agreement [19 20]
5 Electron Neutrino andAntineutrino Appearance
A search for ]119890and ]
119890appearance in the ]
120583and ]
120583beams
enables a measurement of the mixing angle 12057913 It is critical
to know the level of background to the ]119890sample in the
FD The energy spectrum of background events measured inthe ND is used to predict the spectrum expected in the FDHowever the background consists of three components NCinteractions CC ]
120583and ]
120583interactions and the intrinsic ]
119890
component in the beam The relative contribution betweenthe ND and FD is different for all of these components sincethey are affected differently by oscillation and the kinematicsof the production in the beam are different Therefore each
backgroundmust be individually measuredTheNuMI beamcan be configured to produce neutrino beams of varyingenergy by altering the current passing through the magnetichorns and changing the relative positions of the target andhorns Between these different beam configurations therelative contributions of the three background componentschange in a well-understood way as shown in Figure 15By comparing the ND data to the simulation in the threedifferent beam configurations shown in the figure the contri-butions of the three background components can be extracted[71]
Using the data-driven background extraction procedurea total of 1277 background events are expected at the FDin the neutrino-dominated beam and 175 events in theantineutrino-enhanced beam In the data 152 and 20 eventsare observed respectively Figure 16 shows the energy spectraof these events divided into bins of the library eventmatchingdiscriminant variable Although CC ]
119890and ]119890events cannot
be separated on an event-by-event basis the change inthe relative numbers of neutrino and antineutrino inter-actions between the neutrino-dominated and antineutrino-enhanced beams is well knownThis allows separate limits tobe placed on the rates of ]
120583rarr ]119890and ]120583rarr ]119890transitions
on a statistical basis
10 Advances in High Energy PhysicsRa
tio to
no
osci
llatio
ns
05
1
15
2
25
0 10 15 20 30 50
MINOS far detector data
5Reconstructed 120583 energy (GeV)
1071 times 1020 POT
Prediction Δm2 = 241 times 10minus3eV2
Low energy beam 120583-mode
Figure 11 The ratio of the observed ]120583energy spectrum to the
expectation in the case of no oscillation in the neutrino-dominatedbeam The black points show the data the blue line shows the bestfit to the data
075 080 085 090 095 10015
20
25
30
35
40
90 CL68 CL
90 CL
sin2(2120579)
|Δm
2|(10minus3eV
2)
MINOS 3788 kt-yr atmospheric
336 times 1020 POT 120583 modeSuper-K zenith anglelowast
Super-K LElowast
T2Klowastlowast
lowastNeutrino 2012lowastlowastPRD 85 031103(R) (2012)
1071 times 1020 POT 120583 mode
Figure 12 The allowed regions for the atmospheric oscillationparameters |Δ1198982| and sin2(2120579) assuming identical neutrino andantineutrino oscillation parametersTheMINOS result is comparedto measurements from Super-Kamiokande [61] and T2K [62]
The data are fit to extract a measurement of 12057913 The
resulting measurement is shown in Figure 17 The measuredvalue of 120579
13depends on the CP violating phase 120575 which
directly affects the ]119890and ]
119890appearance probabilities and
themass hierarchy which affects the appearance probabilitiesthrough the interactions of the neutrinos with the matter in
MINOS 120583 disappearance1071 times 1020 POT 120583 mode336 times 1020 POT mode3788kt-yr atmospheric
90 CL120583120583120583 + 120583
120583120583120583 + 120583
Best fit
sin2(2120579) or sin2(2120579)
(|Δm
2|
or Δ
m2|)
(10minus3eV
2)
075 080 085 090 095 100
20
25
30
35
120583
|Figure 13 The allowed region for antineutrino oscillation param-eters (blue line) compared to the region measured with neutrinosalone (red line) and the region measured using both neutrinos andantineutrinos under the assumption they have the same parameters(black line)
20
25
30
20 25 30
|Δm
2| (10
minus3eV
2)
|Δm2| (10minus3eV2)
68 CL|Δm2| = |Δm2|
MINOS 120583 disappearance1071 times 1020 POT 120583 mode336 times 1020 POT mode3788kt-yr atmospheric
90 CLBest fit
120583
Figure 14 A comparison of the measured limits on the masssplittings of neutrinos and antineutrinos
the Earthrsquos crust Assuming a normal mass hierarchy 120575 = 0and 120579
23lt 1205874 MINOS measures 2sin2(2120579
13)sin2(120579
23) =
0051+0038
minus0030 Assuming an inverted mass hierarchy 120575 = 0
and 12057923
lt 1205874 MINOS measures 2sin2(212057913)sin2(120579
23) =
0093+0054
minus0049 This measurement is consistent with the results
from reactor neutrino searches [72ndash74] and the T2K experi-ment [75]
This MINOS measurement is the first ever search for ]119890
appearance in a long-baseline ]120583beam and the first search
Advances in High Energy Physics 11
Reconstructed energy (GeV)0 6 8
Frac
tion
of ev
ents
0
01
02
03
04
Standard MC
MINOS
2 4
Near detector 2011
NC120583-CCe-CC
(a)
Horn-off MC
Reconstructed energy (GeV)0 6 8
Frac
tion
of ev
ents
0
01
02
03
04 MINOS
2 4
Near detector 2011
NC120583-CCe-CC
(b)
High energy MC
Reconstructed energy (GeV)0 6 8
Frac
tion
of ev
ents
0
01
02
03
04 MINOS
2 4
Near detector 2011
NC120583-CCe-CC
(c)
Figure 15 The contribution of the three components to the background in the ]119890appearance search as simulated in the ND (a) the regular
(low energy) beam data (b) with no current in the NuMI focusing horns (c) a high energy beam configuration
for ]119890and ]119890appearance with significant matter effects Both
of these effects provide some sensitivity to the neutrinomass hierarchy and CP violation when the MINOS data iscompared to the measurements made by reactor neutrinosearches [72ndash74] (we have calculated a limit of sin2(2120579
13) =
0098 plusmn 0013 from the reactor data at the time of analysis)The sensitivity of MINOS to the mass hierarchy and CPviolation is modest but this contributes to the first analysisof the type that will be used by all future long-baselineexperiments The resulting values of the likelihood by whichMINOS disfavours various values of these parameters areshown in Figure 18 [76]
6 Search for Sterile Neutrino Mixing UsingNeutral-Current Interactions
The energy spectrum of NC interactions in the FD should beunchanged by standard neutrino oscillationThe existence ofone or more sterile neutrino flavours ]
119904 could cause a deficit
in the observed NC interaction rate As with all the MINOSoscillation analyses the energy spectrum of NC interactionsobserved in the ND (which was shown in Figure 8) is usedto predict the spectrum expected at the FD [77] The FDexpectation is shown in Figure 19 with the dashed blue linetaking into account ]
119890appearance corresponding to 120579
13=
115∘ (at the limit set by CHOOZ [78] and a little above
the current accepted value [29 72ndash75] this analysis usesonly the first 707 times 10
20 protons on target of data andwas performed before the recent positive measurements ofa nonzero 120579
13) The data are also shown in the figure and
are in good agreement with the expectation confirming thestandard model of neutrino oscillation This agreement canbe quantified using a test statistic 119877
119877 =119873data minus 119861CC
119878NC (7)
where 119873data is the number of events observed 119861CC is thepredicted background of CC interactions and 119878NC is the
predicted number of NC interactions A value of 119877 = 101 plusmn
006(stat) plusmn 005(syst) is obtained (over the full energy range0ndash120GeV) which is in good agreement with the expectationof 119877 = 1 in the case of no mixing with sterile neutrinos
The data are analysed with a model that assumes a singlesterile neutrino flavour mixing through the addition of afourth neutrino mass state119898
4≫ 1198983 This introduces a mass
splitting Δ119898243
with magnitude O(1 eV2) such that no oscil-lation-induced change to the event rate is observed at theND and the oscillatory energy dependence of the induceddepletion at the FD is so rapid that an overall uniform deple-tion is observed once the energy resolution of the detectors isaccounted forThismodel introduces three additionalmixingangles 120579
14 12057924 and 120579
34 MINOS is insensitive to 120579
14but sets
limits of 12057924= (00
+5
minus00)∘ and 120579
34= (00
+25
minus00)∘ These limits are
evaluated assuming 12057913at the CHOOZ limit
The limit on the coupling of sterile to active neutrinos canbe quantified by defining 119891
119904 the fraction of disappearing ]
120583
which have oscillated into ]119904
119891119904=
119875]120583rarr ]119904
1 minus 119875]120583rarr ]120583
(8)
For the model used in which 1198984≫ 119898
3 119891119904is evaluated
at 14 GeV the energy of maximal ]120583disappearance To
determine the limit on 119891119904 a large number of test values
are chosen of the mixing angles 12057924 12057934 and 120579
23 from
Gaussian distributions according to the measured values and1120590 uncertainties given above (with 120579
23constrained from the
measurements with CC ]120583interactions) 119891
119904is calculated for
each case and the value of 119891119904that is larger than 90 of the
test cases represents the limit MINOS limits 119891119904lt 040 at the
90 confidence level
7 The Future MINOS+
The MINOS experiment has made some very importantcontributions to our understanding of neutrino oscillation
12 Advances in High Energy Physics
Reconstructed energy (GeV)
Reconstructed energy (GeV)
Even
ts
30
0
10
20
Even
ts
30
0
10
20
Even
ts
30
0
10
20
2 4 6 8
2 4 6 8
Reconstructed energy (GeV)2 4 6 8
06 lt 120572LEM lt 07
MINOS far detector data
07 lt 120572LEM lt 08
120572LEM gt 08
mode
mode
mode
e CC signal
e CC signalBackgroundData
(a)
Even
ts
Reconstructed energy (GeV)2 4 6 8
Reconstructed energy (GeV)2 4 6 8
Reconstructed energy (GeV)2 4 6 8
06 lt 120572LEM lt 07
MINOS far detector data
Merged for fit
07 lt 120572LEM lt 08
120572LEM gt 08
mode
mode
mode
8
6
4
2
0
Even
ts
8
6
4
2
0
Even
ts
8
6
4
2
0
e CC signal
e CC signalBackgroundData
5ndash8GeV bins
(b)
Figure 16 The CC ]119890(a) and ]
119890(b) candidate events selected in the FD compared to the expectation without any ]
119890appearance (red) and
with the best fit for 12057913(purple) The events are divided into bins of the library event matching discriminant variable
Advances in High Energy Physics 13
20
15
10
05
000 01 02 03 04
2sin2(212057913)sin212057923
Δm2 gt 0
sin
120575(120587)
(a)
20
15
10
05
000 01 02 03 04
2sin2(212057913)sin212057923
MINOS best fit 12057923 lt 1205874
MINOS best fit 12057923 gt 1205874
Δm2 lt 0
MINOS
106 times 1020 POT -mode33 times 1020 POT -mode
68 CL 12057923 lt 1205874
90 CL 12057923 lt 1205874
120575(120587)
(b)
Figure 17 The allowed regions for 2sin2(212057913)sin2(120579
23)
120575(120587)
Δm2 gt 0 12057923 gt 1205874
Δm2 gt 0 12057923 lt 1205874
Δm2 lt 0 12057923 gt 1205874Δm2 lt 0 12057923 lt 1205874
3
2
1
00 1 1505 2
MINOS
90 CL
68 CL
minus2Δ
(L)
ln
Figure 18 The values of likelihood 119871 by which various values oftheCP violating parameter 120575 the mass hierarchy and the octant of12057923are disfavouredThis analysis uses MINOS data and information
from reactor neutrino measurements of 12057913[72ndash74]
physics and has finished taking data with the low energybeam for which it was designed However the experimentwill continue taking data and producing new results for thenext few years as MINOS+ [79] The NuMI beam is being
20
2018161410 12
Far detector data
Even
ts (G
eV)
00 2 4 6 8
40
60
80
100
120
140
12057913 = 0∘
12057913 = 115∘ 120575 = 120587 Δm232 gt 0
120583 CC background|Δm2
32| = 232 times 10minus3eV2
Ereco (GeV)
sin2212057923 = 1
Figure 19 The black dots show the energy spectrum of NCinteractions observed in the far detector The red lines show theexpectation in the case of no sterile neutrinos and 120579
13= 0 the blue
dashed line shows the same expectation with 12057913= 115
∘
upgraded to a higher energy and intensity for the NO]Aexperiment the far detector of which will sit 14 mrad offaxisNO]A will receive a narrow-band beam peaking at around2GeV which is ideal for searching for ]
119890appearance since
the background seen in MINOS from NC interactions ofhigh energy neutrinos will be heavily reduced Figure 20shows that the MINOS FD will see an intense ]
120583beam
14 Advances in High Energy Physics
1000
500
00 5 10 15 20
E (GeV)
MINOS+NOAMINOS
Preliminary
Simulated beam54 kton 6 times 1020 POT
120583CC
even
ts (G
eV)
Figure 20 The ]120583energy spectrum that will be observed by the
MINOS+ FD compared to the spectra observed by MINOS andNO]A
peaking at around 7GeV In this configuration MINOS+ willobserve around 4000 CC ]
120583interactions in the FD each
year unprecedented statistics for a long-baseline oscillationexperimentThis will offer a unique high precision test of thethree-flavour oscillation paradigm
MINOS+ will be able to make a very sensitive searchfor the sterile neutrinos suggested by the LSND [80] andMiniBooNE [81 82] data and by some interpretations ofreactor neutrino data [83] This search will cover more thanthree orders of magnitude in the mass splitting between thesterile and active neutrinos The signal that MINOS+ willsearch for is illustrated in Figure 21 Figure 21(a) illustratesthe increase in statistical precision thatMINOS+will provideon the ratio of the observed CC ]
120583interaction rate to
that expected without oscillations Figure 21(b) shows howthis ratio is modified if a sterile neutrino exists and mixeswith the active neutrinos an additional deficit of muonneutrino interactions occurs in the higher energy region ofthe spectrum In the model assumed here which introducesa single sterile neutrino state three new mixing angles areintroduced 120579
14 12057924 and 120579
34 An additional mass splitting
Δ1198982
43is also introduced The position in energy of the
additional deficit is governed by the value of the new masssplittingThemagnitude of the additional deficit in the CC ]
120583
interaction rate is governed primarily by the size of 12057924 this is
in comparison to short-baseline searches for ]119890disappearance
from reactors which are governed by 12057914and searches for ]
119890
appearance in ]120583beamswhich are governed by a combination
of 12057914
and 12057924 A detailed explanation of the global effort to
search for sterile neutrinos can be found in [84]The sensitivity of the MINOS+ experiment when com-
bined with the Bugey reactor neutrino data [85] is shown in
MINOS+ simulation
MINOS 1071 times 1021 POT06 times 1021 POT12 times 1021 POT18 times 1021 POT
120583su
rviv
al p
roba
bilit
y
Neutrino energy (GeV)0 5 10 15
15
1
05
0
(a)
P(
120583rarr
120583)
No sterile neutrinosΔm2
43 = 2 times 10minus2eV2 sin2(212057924) = 02
0 5 10 15 20
1
0
18
06
04
02
Neutrino energy (GeV)
(b)
Figure 21 (a) The black points show the ratio of the observed ]120583
energy spectrum to the expectation in the case of no oscillation inthe neutrino-dominated beam of MINOS The blue region showsthe statistical precision expected from MINOS+ (b) The black lineshows the muon neutrino survival probability in the case of nosterile neutrinos the red line shows how the probability would bemodified by the addition of mixing with a sterile neutrino
Figure 22 MINOS+ has the potential to rule out much of theLSND allowed region MINOS+ will begin taking data in thelate summer of 2013 and will continue taking data for at leasttwo years (Figure 22 assumes two years of data taking with aneutrino-dominated beam)
8 Conclusion
The MINOS experiment was conceived at a time when neu-trino oscillation had only recently been confirmed as thesolution to the problem of neutrino flavour change It has
Advances in High Energy Physics 15
Δm
2
10minus210minus2
10minus1
10minus1
10minus310minus4 1
1
10
102
LSND 90 CLLSND 99 CLKarmen2 90 CLBugey 90 CLlowast
MiniBooNE 90 CLMiniBooNE 99 CLMINOS+ and Bugeycombination 90 CL
sin22120579120583e
lowastGLoBES 2012 fit with new reactor fluxescourtesy of P Huber
Figure 22 The sensitivity of MINOS+ to the existence of sterileneutrinos when combined with data from the Bugey [85] reactorneutrino experiment Δ1198982 is the splitting between the three knownneutrino mass states and a new fourth state 120579
120583119890is the mixing angle
governing ]120583rarr ]119890transitions when a fourth sterile neutrino state
is introduced into the PMNSmixingmatrixThis figure assumes twoyears of MINOS+ running with a neutrino-dominated beam
played a hugely influential role in bringing neutrino oscilla-tion physics into an era of precision measurement MINOSrsquosmeasurement of the largest neutrino mass splitting is themost precise in the world MINOS has made the first directprecision measurement of the corresponding antineutrinoparameters a measurement that promises to remain theworldrsquos most precise for many years And MINOS has playeda role in the discovery of a nonzero value for 120579
13
Now that the value of 12057913is known the neutrino physics
community can move on to determine the neutrino masshierarchy and to search for CP violation in the neutrinosector MINOS has pioneered a number of techniques thatwill be used by future experiments The two-detector setupall important in reducing the impact of systematic uncer-tainties is the design of choice for any new experiment andMINOS has demonstrated methods of using a near detectorto determine the expectation at a far detector MINOS hasperformed the first search for ]
119890appearance in a ]
120583beam
and the first search for ]119890and ]119890appearance with significant
matter effects demonstrating the analysis techniques that willbe used to determine the mass hierarchy and CP violationparameter
In the second half of 2013 MINOS will begin taking dataas the MINOS+ experiment which will make ever more pre-cise tests of the three-flavour neutrino oscillation paradigmand set world-leading limits on the existence of sterileneutrinos This is an exciting future for an experiment thatwith a decade of data taking so far has already created alasting legacy for itself in our understanding of the neutrino
A comparison of themeasured neutrino and antineutrinomass splittings is shown in Figure 14 the difference betweenthe two is constrained to |Δ119898
2| minus |Δ119898
2| = (012
+024
minus026) times
10minus3 eV2
Acknowledgment
The work of the MINOS and MINOS+ collaborations issupported by the US DoE the UK STFC the US NSF theState and University of Minnesota the University of Athensin Greece and Brazilrsquos FAPESP and CNPq The authors aregrateful to the Minnesota Department of Natural Resourcesthe crew of the Soudan Underground Laboratory and thepersonnel of Fermilab for their vital contributions
References
[1] S Wojcicki ldquoLong baseline neutrino oscillation programe inthe United Statesrdquo Nuclear Physics B vol 77 no 1ndash3 pp 182ndash186 1999 Proceedings of the 18th International Conference onNeutrino Physics and Astrophysics (Neutrino rsquo98) TakayamaJapan June 1998
[2] R Davis Jr D S Harmer and K C Hoffman ldquoSearch forneutrinos from the sunrdquo Physical Review Letters vol 20 no 21pp 1205ndash1209 1968
[3] A I Abazov O L Anosov E L Faizov et al ldquoSearch forneutrinos from sun using the reactionGa-71 (electron-neutrinoe-) Ge-71rdquo Physical Review Letters vol 67 pp 3332ndash3335 1991
[4] P Anselmann W Hampel G Heusser et al ldquoSolar neutrinosobserved by GALLEX at gran sassordquo Physics Letters B vol 285no 4 pp 376ndash389 1992
[5] M Aglietta G Battistoni E Bellotti et al ldquoExperimentalstudy of atmospheric neutrino flux in the NUSEX experimentrdquoEurophysics Letters vol 8 no 7 article 611 1989
[6] K S Hirata ldquoObservation of a small atmospheric V120583V119890ratio in
Kamiokanderdquo Physics Letters B vol 280 no 1-2 pp 146ndash1521992
[7] R Becker-Szendy C B Bratton D Casper et al ldquoElectron-and muon-neutrino content of the atmospheric fluxrdquo PhysicalReview D vol 46 pp 3720ndash3724 1992
[8] K Daum W Rhode P Bareyre et al ldquoDetermination ofthe atmospheric neutrino spectra with the frejus detectorrdquoZeitschrift fur Physik C vol 66 no 3 pp 417ndash428 1995
[9] S Ahlen M Ambrosio R Antolini and G Auriemma ldquoAtmo-spheric neutrino flux measurement using upgoing muonsrdquoPhysics Letters B vol 357 no 3 pp 481ndash486 1995
[10] WMAllison G J Alner D S Ayres et al ldquoMeasurement of theatmospheric neutrino flavour composition in Soudan 2rdquoPhysicsLetters B vol 391 no 3-4 pp 491ndash500 1997
16 Advances in High Energy Physics
[11] Y Fukuda T Hayakawa E Ichihara et al ldquoEvidence foroscillation of atmospheric neutrinosrdquo Physical Review Lettersvol 81 no 8 pp 1562ndash1567 1998
[12] Q R Ahmad R C Allen T C Andersen et al ldquoMeasurementof charged current interactions produced by solar neutrinos atthe sudbury neutrino observatoryrdquo Physical Review Letters vol87 Article ID 071301 2001
[13] Q R Ahmad R C Allen T C Andersen et al ldquoDirect evidencefor neutrino flavor transformation from neutral-current inter-actions in the sudbury neutrino observatoryrdquo Physical ReviewLetters vol 89 Article ID 011301 6 pages 2002
[14] B Pontecorvo ldquoInverse beta processes and nonconservation oflepton chargerdquo Journal of Experimental and Theoretical Physicsvol 34 pp 172ndash173 1958
[15] V N Gribov and B Pontecorvo ldquoNeutrino astronomy andlepton chargerdquo Physics Letters B vol 28 pp 493ndash496 1969
[16] Z Maki M Nakagawa and S Sakata ldquoRemarks on the unifiedmodel of elementary particlesrdquo Progress of Theoretical Physicsvol 28 no 5 pp 870ndash880 1962
[17] P Adamson C Andreopoulos D J Auty et al ldquoFirst directobservation of muon antineutrino disappearancerdquo PhysicalReview Letters vol 107 no 2 Article ID 021801 2011
[18] P Adamson D J Auty D S Ayres et al ldquoSearch for thedisappearance of muon antineutrinos in the NuMI neutrinobeamrdquo Physical Review D vol 84 no 7 Article ID 071103 6pages 2011
[19] P Adamson D S Ayres C Backhouse et al ldquoImprovedmeasurement of muon antineutrino disappearance inMINOSrdquoPhysical Review Letters vol 108 no 19 Article ID 191801 5pages 2012
[20] P Adamson I Anghel C Backhouse et al ldquoMeasurementof Neutrino and Antineutrino Oscillations Using Beam andAtmospheric Data in MINOSrdquo Physical Review Letters vol 110no 25 Article ID 251801 6 pages 2013
[21] K Anderson B Bernstein D Boehnlein et al ldquoThe NuMIFacility Technical Design Reportrdquo FERMILAB-DESIGN-1998-01 1998
[22] D G Michael P Adamson T Alexopoulos et al ldquoObservationof muon neutrino disappearance with the MINOS detectors inthe NuMI neutrino beamrdquo Physical Review Letters vol 97 no19 Article ID 191801 6 pages 2006
[23] P Adamson C Andreopoulos K E Arms et al ldquoStudy ofmuon neutrino disappearance using the fermilab main injectorneutrino beamrdquo Physical Review D vol 77 no 7 Article ID072002 34 pages 2008
[24] P Adamson C Andreopoulos K E Arms et al ldquoMeasurementof neutrino oscillations with theMINOS detectors in the NuMIbeamrdquo Physical Review Letters vol 101 no 13 Article ID 1318025 pages 2008
[25] P Adamson C Andreopoulos R Armstrong et al ldquoMea-surement of the neutrino mass splitting and flavor mixing byMINOSrdquo Physical Review Letters vol 106 no 18 Article ID181801 6 pages 2011
[26] P Adamson C Andreopoulos K E Arms et al ldquoSearch formuon-neutrino to electron-neutrino transitions in MINOSrdquoPhysical Review Letters vol 103 no 26 Article ID 261802 5pages 2009
[27] PAdamsonCAndreopoulosD J Auty et al ldquoNew constraintsonmuon-neutrino to electron-neutrino transitions inMINOSrdquoPhysical ReviewD vol 82 no 5 Article ID 051102 6 pages 2010
[28] P Adamson D J Auty D S Ayres et al ldquoImproved search formuon-neutrino to electron-neutrino oscillations in MINOSrdquoPhysical Review Letters vol 107 no 18 Article ID 181802 6pages 2011
[29] P Adamson I Anghel C Backhouse et al ldquoElectron neutrinoand antineutrino appearance in the full MINOS data samplerdquoPhysical Review Letters vol 110 no 17 Article ID 171801 6 pages2013
[30] P Adamson C Andreopoulos K E Arms et al ldquoSearch foractive neutrino disappearance using neutral-current interac-tions in theMINOS long-baseline experimentrdquo Physical ReviewLetters vol 101 no 22 Article ID 221804 5 pages 2008
[31] P Adamson C Andreopoulos D J Auty et al ldquoSearch for ster-ile neutrino mixing in the MINOS long-baseline experimentrdquoPhysical Review D vol 81 no 5 Article ID 052004 18 pages2010
[32] P Adamson D J Auty D S Ayres et al ldquoActive to sterileneutrino mixing limits from neutral-current interactions inMINOSrdquo Physical Review Letters vol 107 no 1 Article ID011802 5 pages 2011
[33] Z Pavlovic Observation of disappearance of muon neutrinos inthe NuMI beam [PhD thesis] University of Texas at AustinAustin Tex USA 2008
[34] F Ballarini G Battistoni M Campanella et al ldquoThe FLUKAcode an overviewrdquo Journal of Physics vol 41 article 151 2006
[35] S Agostinelli J Allison K Amako et al ldquoGEANT4mdasha sim-ulation toolkitrdquo Nuclear Instruments and Methods in PhysicsResearch A vol 506 no 3 pp 250ndash303 2003
[36] G Battistoni F Cerutti A Fasso et al ldquoThe FLUKA codedescription and benchmarkingrdquo in Proceedings of the HadronicShower Simulation Workshop vol 896 of AIP Conference Pro-ceedings pp 31ndash49 Batavia Ill USA September 2006
[37] D G Michaele P Adamson T Alexopoulos et al ldquoThe mag-netized steel and scintillator calorimeters of the MINOS exper-imentrdquoNuclear Instruments and Methods in Physics Research Avol 596 no 2 pp 190ndash228 2008
[38] I E Stockdale A Bodek F Borcherding N Giokaris et alldquoLimits on muon-neutrino oscillations in the mass range 30 lt9987791198982lt 1000 eV2c4 rdquo Physical Review Letters vol 52 no 16 pp
1384ndash1388 1984[39] F Dydak G J Feldman C Guyot et al ldquoA search for V
120583
oscillations in the9987791198982 range 03ndash90 eV2 rdquo Physics Letters B vol134 no 3-4 pp 281ndash286 1984
[40] F Bergsma J Dorenbosch M Jonker et al ldquoA searchfor oscillations of muon neutrinos in an experiment withLEcong07 kmGeVrdquo Physics Letters B vol 142 no 1-2 pp 103ndash1101984
[41] M H Ahn E Aliu S Andringa et al ldquoMeasurement ofneutrino oscillation by the K2K experimentrdquo Physical ReviewD vol 74 no 7 Article ID 072003 39 pages 2006
[42] P Adamson T Alexopoulos W W M Allison et al ldquoFirstobservations of separated atmospheric V
120583and ]
120583events in the
MINOS detectorrdquo Physical Review D vol 73 no 7 Article ID072002 2006
[43] P Adamson C Andreopoulos K E Arms et al ldquoCharge-separated atmospheric neutrino-inducedmuons in theMINOSfar detectorrdquo Physical ReviewD vol 75 no 9 Article ID 09200314 pages 2007
[44] P Adamson C Backhouse G Barr et al ldquoMeasurements ofatmospheric neutrinos and antineutrinos in the MINOS fardetectorrdquo Physical Review D vol 86 no 5 Article ID 05200720 pages 2012
Advances in High Energy Physics 17
[45] M A Kordosky Hadronic interactions in the MINOS detectors[PhD thesis] University of Texas at Austin Austin Tex USA2004
[46] P L Vahle Electromagnetic interactions in the MINOS detectors[PhD thesis] University of Texas at Austin Austin Tex USA2004
[47] C Backhouse Measuring neutrino oscillation parameters using]120583disappearance inMINOS [PhD thesis] University of Oxford
Oxford UK 2011[48] T M Cover and P E Hart ldquoNearest neighbor pattern classifi-
cationrdquo IEEE Transactions on Information Theory vol 13 no 1pp 21ndash27 1967
[49] R Ospanov A measurement of muon neutrino disappearancewith the MINOS detectors and NuMI beam [PhD thesis]University of Texas at Austin Austin Tex USA 2008
[50] J S Marshall A study of muon neutrino disappearance with theMINOS detectors and the NuMI neutrino beam [PhD thesis]University of Cambridge Cambridge UK 2008
[51] J P OchoaA search formuon neutrino to electron neutrino oscil-lations in the MINOS Experiment [PhD thesis] The CaliforniaInstitute of Technology Pasadena Calif USA 2009
[52] R TonerMeasuring 12057913via muon neutrino to electron neutrino
oscillations in the MINOS experiment [PhD thesis] Universityof Cambridge Cambridge UK 2011
[53] A Holin Electron neutrino appearance in the MINOS experi-ment [PhD thesis] University College London London UK2010
[54] J Boehm Measurement of electron neutrino appearance withthe MINOS experiment [PhD thesis] Harvard UniversityCambridge Mass USA 2009
[55] G Tinti Sterile neutrino oscillations in MINOS and hadronproduction in pC collisions [PhD thesis] University of OxfordOxford UK 2010
[56] J J EvansMeasuring antineutrino oscillations with the MINOSexperiment [PhD thesis] University of Oxford Oxford UK2008
[57] S J ColemanAmeasurement of neutrino oscillations withmuonneutrinos in the MINOS experiment [PhD thesis] College ofWilliam ampMary Williamsburg Va USA 2011
[58] J S Mitchell Measuring ]120583disappearance with the MINOS
experiment [PhD thesis] University of Cambridge CambridgeUK 2011
[59] A McGowan Observation of deficit in NuMI neutrino-inducedrock and non-fiducial muons in MINOS far detector andmeasurement of neutrino oscillation parameters [PhD thesis]University of Minnesota Minneapolis Minn USA 2007
[60] M StraitMeasurement of neutrino oscillation parameters usinganti-fiducial charged current events in MINOS [PhD thesis]University of Minnesota Minneapolis Minn USA 2010
[61] Y Itow ldquoAtmospheric neutrinosmdashresults from running exper-imentsrdquo in Proceedings of the 25th International Conference onNeutrino Physics and Astrophysics (Neutrino rsquo12) Kyoto JapanJune 2012
[62] K Abe N Abgrall Y Ajima et al ldquoFirst muon-neutrinodisappearance study with an off-axis beamrdquo Physical Review Dvol 85 no 3 Article ID 031103 8 pages 2012
[63] K Nakamura ldquoReview of particle physicsrdquo Journal of Physics Gvol 37 Article ID 075021 2010
[64] L Wolfenstein ldquoNeutrino oscillations in matterrdquo PhysicalReview D vol 17 no 9 pp 2369ndash2374 1978
[65] J W F Valle ldquoResonant oscillations of massless neutrinos inmatterrdquo Physics Letters B vol 199 no 3 pp 432ndash436 1987
[66] M C Gonzalez-Garcia M M Guzzo P I Krastev et alldquoAtmospheric neutrino observations and flavor changing inter-actionsrdquo Physical Review Letters vol 82 no 16 pp 3202ndash32051999
[67] A Friedland C Lunardini and M Maltoni ldquoAtmosphericneutrinos as probes of neutrino-matter interactionsrdquo PhysicalReview D vol 70 no 11 Article ID 111301 2004
[68] Z IsvanAntineutrino oscillations and a Search for non-standardInteractions with the MINOS [PhD thesis] University of Pitts-burgh Pittsburgh Pa USA 2012
[69] W A Mann D Cherdack W Musial and T Kafka ldquoApparentmultiple 998779119898
32
2 in ]120583and V
120583survival oscillations from nonstan-
dard interactionmatter effectrdquo Physical Review D vol 82 no 11Article ID 113010 8 pages 2010
[70] J Kopp P A N Machado and S J Parke ldquoInterpretation ofMINOS data in terms of nonstandard neutrino interactionsrdquoPhysical Review D vol 82 no 11 Article ID 113002 12 pages2010
[71] J A B Coelho Investigacao de mecanismos alternativos aoscilacao de neutrinos no experimentos MINOS [PhD thesis]Universidade Estadual de Campinas Sao Paulo Brazil 2012
[72] F P An Q An J Z Bai A B Balantekin et al ldquoImprovedmeasurement of electron antineutrino disappearance at DayaBayrdquo Chinese Physics C vol 37 Article ID 011001 21 pages 2013
[73] J K Ahn S Chebotaryov J H Choi et al ldquoObservationof reactor electron antineutrinos disappearance in the RENOexperimentrdquo Physical Review Letters vol 108 Article ID 1918026 pages 2012
[74] Y Abe C Aberle J C dos Anjos et al ldquoReactor electronantineutrino disappearance in the Double Chooz experimentrdquoPhysical Review D vol 86 Article ID 052008 2012
[75] K Abe N Abgrall H Aihara et al ldquoEvidence of electronneutrino appearance in a muon neutrino beamrdquo PhysicalReview D vol 88 no 3 Article ID 032002 41 pages 2013
[76] A Schreckenberger Electron neutrino and antineutrino appear-ance in the MINOS detector [PhD thesis] University of Min-nesota Minneapolis Minn USA 2013
[77] D J Koskinen MINOS sterile neutrino search [PhD thesis]University College London London UK 2009
[78] M Apollonio A Baldini C Bemporad et al ldquoSearch forneutrino oscillations on a long base-line at the CHOOZ nuclearpower stationrdquoTheEuropean Physical Journal C vol 27 pp 331ndash374 2003
[79] G Tzanankos M Bishai M Diwan et alMINOS+ a proposalto FNAL to run MINOS with the medium energy NuMI beam[PhD thesis] University of Athens Athens Greece 2011
[80] A Aguilar L B Auerbach R L Burman et al ldquoEvidence forneutrino oscillations from the observation of ]
119890e appearance
in a ]120583beamrdquo Physical Review D vol 64 Article ID 112007 22
pages 2001[81] A A Aguilar-Arevalo C E Anderson S J Brice et al ldquoSearch
for electron antineutrino appearance at the Δ119898 sim 1 eV2 ScalerdquoPhysical Review Letters vol 103 no 11 Article ID 111801 2009
[82] A A Aguilar-Arevalo C E Anderson A O Bazarko et alldquoImproved search for V
120583rarr V119890oscillations in the MiniBooNE
experimentrdquo Physical Review Letter vol 110 no 10 Article ID161801 2013
[83] GMentionM Fechner T Lasserre et al ldquoReactor antineutrinoanomalyrdquo Physical Review D vol 83 Article ID 073006 20pages 2011
18 Advances in High Energy Physics
[84] KNAbazajianMAAcero S KAgarwalla et al ldquoLight sterileneutrinos a white paperrdquo httparxivorgabs12045379
[85] B Achkar R Aleksan M Avenier et al ldquoSearch for neutrinooscillations at 15 40 and 95meters from a nuclear power reactorat Bugeyrdquo Nuclear Physics B vol 434 no 3 pp 503ndash532 1995
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
High Energy PhysicsAdvances in
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
FluidsJournal of
Atomic and Molecular Physics
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in Condensed Matter Physics
OpticsInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
AstronomyAdvances in
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Superconductivity
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Statistical MechanicsInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
GravityJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
AstrophysicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Physics Research International
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Computational Methods in Physics
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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Soft MatterJournal of
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PhotonicsJournal of
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Journal of
Biophysics
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
ThermodynamicsJournal of
Advances in High Energy Physics 3
Neutrino-dominated
True energy (GeV)5 10 15 20 25 300
0
02
04
06
08
1
Near detector simulated Low energy beam
Flux
times120590
CC
(au
)
120583 spectrum120583 spectrum
(a)
True energy (GeV)5 10 15 20 25 300
0
02
04
06
08
1
Near detector simulatedLow energy beam
Antineutrino-enhanced
Flux
times120590
CC
(au
)
120583 spectrum120583 spectrum
(b)
Figure 2The composition of theNuMIbeamwhen configured to produce (a) a neutrino-dominated beamand (b) an antineutrino-enhancedbeam The figures show the rate of charged current neutrino interactions observed in the MINOS near detector
(a) (b)
Figure 3 The MINOS detectors (a) the near detector at Fermilab (b) the far detector at the Soudan Underground Laboratory
inch-thick steel interleaved with planes of 1 cm thick plasticscintillator The scintillator planes are divided into 4 cm widestrips as shown in Figure 4 Along the centre of each strip awavelength shifting fibre collects the scintillation light shiftsit to green wavelengths and takes it out to a photomultipliertube Any charged particles passing through the detectordeposit their energy to produce light the pattern of thesedeposits allows the topology of the neutrino interaction to bereconstructedThe scintillator strips are aligned orthogonallyon adjacent detector planes to allow three-dimensionalreconstructionThe detectors are magnetised to around 13 Tallowing the charge of particles to be identified
The smaller of the two detectors the Near Detector(ND) sits at Fermilab 104 km from the target With amass of 098 kton it measures the energy spectra of theneutrinos before oscillation The far detector is located atthe SoudanUndergroundLaboratory in northernMinnesota705m underground and 735 km from the target With a massof 54 kton it again measures the neutrino energy spectra
seeing the appearance and disappearance of neutrinos due tooscillation
This two-detector arrangement previously used overdistances of around 1 km by experiments such as CCFRCDHS and CHARM [38ndash40] and then over 250 km by K2K[41] is very powerful in reducing systematic uncertaintiesNeutrino physics is beset with uncertainty in particularinteraction cross-sections are unknown to many tens of percent and neutrino fluxes can be mismodeled by similaramounts However these uncertainties affect both the nearand far detectors in very similar ways Thus when a ratio istaken of the energy spectra measured in the two detectorsa cancellation occurs and the effects of the uncertainties aregreatly reduced As an indication of how well this worksdespite the uncertainties of tens of per cent in the simulatedevent rate in the detectors once the near to far detector ratiois taken the normalization is known to 16 this 16 isdominated by the uncertainty in the relative efficiency of theevent reconstruction algorithms between the two detectors
4 Advances in High Energy Physics
PMT assembly
CookieMUX box optical
connectorOptical cable
MUX box
Optical connector
WLS fibers
Scintillator strips
Steel plates
Figure 4 A MINOS detector plane
The MINOS Far Detector is also a very effective detectorof neutrinos produced in the atmosphere Since it wasswitched on in 2003 it has recorded 379 kton-years of datarecording 2072 candidate neutrino interactions that havebeen included into the analyses of the beam data to improvethe precision of the oscillation parameter measurements [2042ndash44]
3 Neutrino Interactions inthe MINOS Detectors
Three types of neutrino interaction shown in Figure 5 areof interest to MINOS Muon neutrinos and antineutrinosinteract through the CC process
]120583(]120583) + 119883 997888rarr 120583
minus(+)+ 1198831015840 (3)
The cascade of hadrons 1198831015840 produces a diffuse shower ofenergy deposits near the interaction vertex The muon pro-duces a long track that curves in the magnetic field thedirection of curvature identifying the incoming neutrino asa ]120583or a ]120583
All active neutrino flavours undergo NC interactionsthrough the process
] + 119883 997888rarr ] + 1198831015840 (4)
Only the hadronic cascade is observed producing a diffuseshower of energy deposits
Finally electron neutrinos undergo CC interactionsthrough the process
]119890+ 119883 997888rarr 119890
minus+ 1198831015840 (5)
The electron gives rise to an electromagnetic shower whichproduces a much denser more compact shower of energydeposits
The energy of the neutrino is determined by summing theenergies of the shower and anymuon trackThemuon energyis determined from the length of stopping tracks leading toa resolution of around 5 and from the curvature in themagnetic field for tracks that exit the detector leading to aresolution of around 10 For NC and ]
119890CC interactions
the energy of the shower is determined through calorimetryThe calorimetric energy resolution for hadronic showers isaround 55radicenergy [45] and for electromagnetic showers20radicenergy [46] For ]120583 CC interactions a more sophisti-cated approach is used to improve the resolution of hadronicshower energy measurement [47] For low energy showers(of a few GeV or below) significant additional information isheld in the topology of the showerThree event characteristicsare used the calorimetric energy deposit within 1m of theinteraction vertex the sum of the calorimetric energy in thetwo largest showers in the event and the physical length ofthe largest shower These variables are input into a 119896-nearest-neighbour algorithm [48] which finds the best matches froma library of simulated events and uses these to estimate thehadronic energyThis improves the shower energy resolutionfrom 55 to 43 for showers between 10GeV and 15 GeV
31 Selection of Charged-Current ]120583and ]
120583Interactions To
make a measurement of 119875(]120583
rarr ]120583) it is necessary to
select a pure sample of ]120583CC interactions This is achieved
by selecting events with a clear muon track The main loss inefficiency comes from events with a high inelasticity in whicha short muon track is hidden in a large hadronic cascade
Advances in High Energy Physics 5
CC 120583 event
120583minus
15
1
05
0
0
05 1 15 2 25 3 35 4
Longitudinal position (m)
Tran
sver
se p
ositi
on (m
)
minus05
(a)
V
06
04
02
0
minus02
minus02
minus04
minus04
minus06
0 02 04 06 08 1
NC event
Longitudinal position (m)
Tran
sver
se p
ositi
on (m
)
(b)
e
02
0
02
0 05 1
CC e event
Longitudinal position (m)
Tran
sver
se p
ositi
on (m
)
lowast
(c)
Figure 5 Neutrino interaction topologies observed in the MINOS detectors (a) A CC ]120583interaction (b) A NC interaction (c) A CC ]
119890
interaction Each coloured rectangle represents an excited scintillator strip the colour indicating the amount of light purple and blue are lowlight levels through to orange and red for the highest light levels
The main background occurs at low energies and consists ofsmall cascades from NC interactions in which a low energyhadron such as a proton or a charged pion exhibits a track-like topology that mimics a low energy muon Four variablesare constructed that discriminate between muons trackswhich are typically long and show a constant energy deposi-tion along the length and spurious hadronic tracks which aretypically shorter and show greater fluctuations in the energydeposition These variables are the event length the averageenergy deposited per scintillator plane along the track thetransverse energy deposition profile and the fluctuation of
the energy deposition along the track These variables areinput into a 119896-nearest-neighbour algorithm which calculatesa single discrimination variable shown in Figure 6 [49]Events for which this variable is greater than 03 are selectedas CC ]
120583interactions yielding a sample with a total efficiency
of 90 below 2GeV the NC contamination is 65 Theefficiency and contamination are energy dependent this fullenergy dependence is shown in Figure 6
The CC interactions of ]120583and ]
120583result in very similar
topologies the 119896-nearest-neighbour discriminant is thereforeused in the same way in both the neutrino-dominated and
6 Advances in High Energy Physics
CCNC separation parameter
Low energy beamDataMC expectation
NC background
Even
ts10
16PO
T
10
1
10minus1
10minus2
0 02 04 06 08 1
(a)
Reconstructed neutrino energy (GeV)
0
02
04
06
08
1
NC contamination
Far detector fiducial onlyCC selection efficiency
0 2 4 6 8 10
Effici
ency
con
tam
inat
ion
(b)
Figure 6 (a) The discrimination variable used to separate ]120583CC interactions from hadronic backgrounds Events with a parameter value
greater than 03 are selected as ]120583CC interactions (b) The efficiency and background contamination of the selected ]
120583CC sample in the far
detector
antineutrino-enhanced beams When performing a directmeasurement of the antineutrino oscillation parameters anadditional selection cut is made requiring the charge of themuon track to be positiveThis uses the direction of curvatureof themuon asmeasured by aKalman Filter algorithm [50] Afurther sample of ]
120583CC interactions is obtained from the 7
]120583component in the neutrino-dominated beamThis sample
contains a significant background of ]120583events in which a 120583minus
has been identified with the incorrect charge often at lowenergies where the muon undergoes significant scatteringTherefore a much stricter set of selection criteria are appliedto purify this ]
120583sample [18]
32 Selection of Charged-Current ]119890Interactions The selec-
tion of ]119890CC interactions focuses on identifying the dense
showers from the electromagnetic interaction of the electronrather than the much more diffuse hadronic showers Theprimary background comes from purely hadronic showerswhich can have a denser than average energy depositparticularly in the presence of a neutral pion decaying tophotons Once a set of shower-like events in the signalregion of 1ndash8GeV has been obtained a pattern matchingapproach called library event matching is used to identifythe interactions most likely to be ]
119890CC [51 52] Each event
in the data is compared to a library of 5 times 107 simulated
signal and background events its similarity to the libraryevents is quantified by comparing the pattern of energydeposits in each scintillator strip excited by the shower wherethe energy deposit is quantified by the charge recorded onthe photomultiplier tube For an arbitrary energy depositthe mean expected charge on a photomultiplier tube willbe some value 120582 The probability of observing an amountof charge 119899 is then a Poisson distribution 119875(119899 | 120582) Thelikelihood L of a data event corresponding to the same
physical shower topology as a simulated library event cantherefore be calculated as
logL =
119873strips
sum
119894=1
log [intinfin
0
119875 (119899119894
data | 120582) 119875 (119899119894
lib | 120582) d120582] (6)
where 119894 represents the 119894th scintillator strip in the showerUsing this definition of the likelihood the 50 library eventsare identified that best match the data eventThree quantitiesare calculated from this set of 50 best-matching library eventsthe fraction of the events that are true ]
119890CC events the
average inelasticity of the true ]119890CC events and the average
fraction of charge that overlaps between the data event andeach ]
119890CC library event These three quantities are input to
a neural network which calculates a classification variableshown in Figure 7 Events with a classification variable valueabove 06 are selected for analysis this value was chosen tomaximise the sensitivity to ]
119890and ]119890appearance
The efficiency of the ]119890CC selection is estimated from
the data rather than relying totally on the simulation Toobtain a pure sample of true hadronic showers a sampleof well-identified ]
120583CC events is selected and the energy
depositions corresponding to the muon track are removed[53]The simulated energy depositions of an electron are theninserted [54] providing a realistic sample of ]
119890CC events
Using thismethod the ]119890CC identification efficiency is found
to be (574 plusmn 28) in the neutrino-dominated beam and(633 plusmn 31) in the antineutrino-enhanced beam
33 Selection of Neutral-Current Interactions The signal of anNC interaction is a diffuse hadronic shower ]
120583CC interac-
tions also produce hadronic showers and if the inelasticityis high the tell-tale muon track may not visibly extend pastthe shower To purify a sample of NC interactions a simple
Advances in High Energy Physics 7
sin2(212057913) = 01
Δm232 gt 0 120575cp = 0 12057923 =
120587
4
Background
MINOS far detector80
60
40
20
00 01 02 03 04 05 06 07 08 09 1
LEM discriminant
Signal times10
Even
ts8
2times10
20PO
T
(a)
LEM discriminant
Even
ts10
19PO
T
DataMonte Carlo
MINOS near detector8000
6000
4000
2000
00 01 02 03 04 05 06 07 08 09 1
(b)
Figure 7 (a) The library event matching discriminant showing the expected distribution for background and CC ]119890signal events in the far
detector in the neutrino-dominated beam Note that the signal simulated for sin2(212057913) = 01 120575 = 0 and a normal mass hierarchy has been
scaled up by a factor of ten for visibility (b)The same discriminant as observed in the near detector compared with the simulated expectation
Near detector dataMonte Carlo prediction
20
10
30
50
2018161410 120
0 2 4 6 8
40
60
120583 CC background
Ereco (GeV)
104
even
ts (G
eV)
Figure 8 The sample of events identified as NC interactions in thenear detector
cut-based approach is taken [55] events are classified asNC-like if the event contains no reconstructed track or ifthe track extends no more than six planes past the end ofthe shower The resulting distribution of NC interactions inthe near detector is shown in Figure 8 The NC identificationefficiency is 89 with 61 purity This selection will identify97 of ]
119890CC interactions as NC events therefore an analysis
of NC interactions in the FD must account for the ]119890
appearance caused by a nonzero 12057913
34 Selection of Atmospheric Neutrinos Atmospheric neu-trino interactions are selected out of any activity seen in
the FD outside of the 10 120583s periods when the NuMI beamis active [44] The oscillation signal is contained in the ]
120583
CC interactions and as with the beam-induced interactionsthese are identified by the presence of a muon track The FDbegan taking data with atmospheric neutrinos in July 2003two years before the NuMI beam began running
The FD has a single-hit timing resolution of 25 ns Thistiming information is used to determine the direction inwhich the detector activity is traveling Any downwardstraveling activity is required to begin well inside the detec-tor to eliminate cosmic muons entering from above Allupwards or horizontally traveling activity is almost certainto be neutrino-induced since no other particle can survivethrough the many kilometres of rock All activity with azenith angle of cos 120579
119911lt 014 is defined as horizontal or down-
going this corresponds to an overburden of at least 14 kmwater equivalent
From this sample of neutrino-induced activity all eventswith a track crossing at least eight planes are designatedtrack-like all events with only shower-like activity crossing atleast four planes are designated shower-like These track-likeand shower-like samples are used in the neutrino oscillationmeasurementsThe track-like sample contains the oscillationsignal of ]
120583disappearance The shower-like sample contains
mainly NC interactions and ]119890and ]
119890CC interactions it
shows little oscillation signal but is very important for settingthe normalization of the atmospheric neutrino flux
4 Muon Neutrino andAntineutrino Disappearance
The atmospheric oscillation parameters |Δ1198982| and sin2(2120579)aremeasured by observing and fitting the energy dependenceof ]120583and ]
120583disappearance To minimise the impact of
8 Advances in High Energy Physics
20
40
60
80
100
120
0 10 15 20 30 50
Even
tstimes10
4(G
eV)
MINOS near detector dataMCMC uncertaintyNC background
MINOS near detectorLow energy beam 120583-mode729 times 1020 POT
Reconstructed 120583 energy (GeV)5
Figure 9 The energy spectrum of ]120583CC interactions observed in
the ND compared to the simulation
systematic uncertainties the energy spectra of the ]120583and
]120583CC interactions observed in the ND (shown in Figure 9
for the neutrino-dominated beam) are used to predict thespectrum at the FD in the absence of oscillation [23 56]The neutrino energy spectra at the ND and FD are notidentical the ND subtends a relatively large angle to thebeam so for each pion or kaon a range of decay anglescan produce a neutrino that passes through the detectorcorresponding to a range of neutrino energies However theFD is effectively a point when viewed from the neutrinoproduction location so a single decay angle for each hadrontherefore a single neutrino energy contributes to the fluxTo take this difference into account the hadron-decay kine-matics are encoded into a beam transfer matrix that convertsthe observed ND flux into a predicted FD flux Once theND data has been used in this way the most importantsystematic uncertainties are those that can affect the twodetectors differently primarily reconstruction efficienciesand miscalibrations of the neutrino energy measurementin the detectors [57] These uncertainties are included inthe fit that extracts the oscillation parameters [58] Theuncertainty on the reconstruction efficiency is modeled as a16 uncertainty on the relative rate of events between theND and FD The uncertainty on the measurement of muonenergy has two components that are fully correlated betweenthe detectors a 2 uncertainty on energies measured fromrange and a 3 uncertainty on energies measured fromthe curvature in the magnetic field The uncertainty in thehadronic energy measurements also has two componentsAn uncertainty arising from shower modeling uncertaintiesand calibration is fully correlated between the detectorsand is parameterized as (66 + 35119890119864shw14GeV) The secondcomponent is uncorrelated between the detectors and is 19
in theND and 11 in the FD this is dominated by calibrationuncertainties
The top row of Figure 10 shows the predicted spectra of]120583and ]120583CC interactions from the neutrino-dominated and
antineutrino-enhanced beams at the FD along with the dataIn the neutrino-dominated beam an additional sample isused consisting of neutrinos interacting outside the fiducialvolume of the detector and in the rock surrounding thedetector [59 60] This nonfiducial sample consists mainlyof high energy neutrinos and has significantly lower res-olution as not all the energy is contained in the detectorhowever it does contain some oscillation information Intotal 8100 reconstructed neutrino events are used in theanalysis without oscillations 9471 would be expected Inall samples a clear energy-dependent deficit of ]
120583and
]120583interactions is observed The ratio of the data to the
expectation for the ]120583interactions in the neutrino-dominated
beam is shown in Figure 11This ratio shows the ldquodip and riserdquoenergy dependence of the deficit which is characteristic ofoscillation and described by (1)
The bottom row of Figure 10 shows the spectra of atmo-spheric ]
120583and ]120583CC interactions as a function of 119871119864 where
119871 is the distance traveled by the neutrino and 119864 is its energyThe atmospheric neutrino events are divided into ]
120583and ]120583
interactions according to the direction of curvature of themuon and separated into samples depending on whether ornot the interaction vertex is contained in the detector
All the observed ]120583and ]120583CC interactions are fit accord-
ing to the two-flavour model of (1) under the assumptionthat neutrinos and antineutrinos have the same oscillationparametersThe resultingmeasurement of |Δ1198982| and sin2(2120579)is shown in Figure 12 The fit yields |Δ1198982| = (241
+009
minus010) times
10minus3 eV2 and sin2(2120579) = 0950
+0035
minus0036 disfavouring maximal
mixing at the 86 confidence level Figure 12 compares thismeasurement to those from Super-Kamiokande [61] andT2K [62] The MINOS measurement is the most precisedetermination of |Δ1198982| and all measurements of sin2(2120579) areconsistent
41 Muon Antineutrino Disappearance In the standardmodel of neutrino oscillation neutrinos and antineutrinosobey the same parameters with CPT symmetry requiringthat the masses of particles and antiparticles are identicalThe most sensitive test of this symmetry in other sectors isfrom the kaon system [63] The data from the antineutrino-enhanced beam and the interaction of atmospheric antineu-trinos enables the first direct comparison of the neutrinoand antineutrino oscillation parameters in the atmosphericregion This comparison provides a limit on nonstandardinteractions with the matter being passed through by theneutrino beam [64ndash70]
Figure 10 showed the energy spectra of ]120583interactions
observed in the FD These spectra can be fit in the two-flavour model of (1) allowing the antineutrino oscillationparameters to differ from those for neutrinos This fit yieldsthe antineutrino parametermeasurement shown in Figure 13|Δ1198982| = (250
+023
minus025) times 10
minus3 eV2 and sin2(2120579) = 097+003
minus008
This is in excellent agreement with the parameters measured
Advances in High Energy Physics 9
Neutrino energy (GeV) Neutrino energy (GeV) Neutrino energy (GeV)
0
20
40
60
80
0
5
10
10
15
1515
20
20
25
25
30
Muon energy (GeV)
0
200
400
600
800
0
100
200
300
400
500
6001071 times 1020 POT
Even
ts (G
eV)
Even
ts (G
eV)
Even
ts (G
eV)
Even
ts (G
eV)
120583 120583
120583120583
0 02 4 56 0 2 4 68 910 12 14 0 2 4 6 8 10 12 14
Neutrino beam Neutrino beam Neutrino beam Antineutrino beam
contained-vertex 120583
nonfiducial 120583contained-vertex 120583
contained-vertex 120583 336 times 1020 POT
(a)
0
20
40
60
0
10
20
30
0
10
20
30
0
5
10
15
20
25
MINOS dataBest fit oscillationsNo oscillations
NC backgroundCosmic-ray muons
120583 120583 120583 120583
0 1 2 3 4 0 1 2 3 4 0 1 2 3 4 0 1 2 3 4
Even
ts
Even
ts
Even
ts
Even
ts
Atmos contained-vertex 120583 Atmos nonfiducial 120583minus Atmos nonfiducial 120583+3788kton-years
Atmos contained-vertex 120583
log10( (km)E (GeV)) log10( (km)E120583 (GeV))L L log10( (km)E (GeV))L log10( (km)E120583 (GeV))L
(b)
Figure 10 The energy spectra of ]120583and ]
120583CC interactions observed at the FD compared to the expectation with and without oscillation
(a) shows beam-induced neutrinos (b) shows atmospheric neutrinos
with neutrinos alone (the red line in Figure 13) It should benoted that the first MINOS measurement of the antineutrinooscillation parameters released in 2010 [17] yielded a notabletension between the ] and ] oscillation parameters whichwere in agreement only at the 20 confidence levelThis ten-sion was shown to be a statistical fluctuation as the additionof further data brought the ] and ] parameters measurementsinto good agreement [19 20]
5 Electron Neutrino andAntineutrino Appearance
A search for ]119890and ]
119890appearance in the ]
120583and ]
120583beams
enables a measurement of the mixing angle 12057913 It is critical
to know the level of background to the ]119890sample in the
FD The energy spectrum of background events measured inthe ND is used to predict the spectrum expected in the FDHowever the background consists of three components NCinteractions CC ]
120583and ]
120583interactions and the intrinsic ]
119890
component in the beam The relative contribution betweenthe ND and FD is different for all of these components sincethey are affected differently by oscillation and the kinematicsof the production in the beam are different Therefore each
backgroundmust be individually measuredTheNuMI beamcan be configured to produce neutrino beams of varyingenergy by altering the current passing through the magnetichorns and changing the relative positions of the target andhorns Between these different beam configurations therelative contributions of the three background componentschange in a well-understood way as shown in Figure 15By comparing the ND data to the simulation in the threedifferent beam configurations shown in the figure the contri-butions of the three background components can be extracted[71]
Using the data-driven background extraction procedurea total of 1277 background events are expected at the FDin the neutrino-dominated beam and 175 events in theantineutrino-enhanced beam In the data 152 and 20 eventsare observed respectively Figure 16 shows the energy spectraof these events divided into bins of the library eventmatchingdiscriminant variable Although CC ]
119890and ]119890events cannot
be separated on an event-by-event basis the change inthe relative numbers of neutrino and antineutrino inter-actions between the neutrino-dominated and antineutrino-enhanced beams is well knownThis allows separate limits tobe placed on the rates of ]
120583rarr ]119890and ]120583rarr ]119890transitions
on a statistical basis
10 Advances in High Energy PhysicsRa
tio to
no
osci
llatio
ns
05
1
15
2
25
0 10 15 20 30 50
MINOS far detector data
5Reconstructed 120583 energy (GeV)
1071 times 1020 POT
Prediction Δm2 = 241 times 10minus3eV2
Low energy beam 120583-mode
Figure 11 The ratio of the observed ]120583energy spectrum to the
expectation in the case of no oscillation in the neutrino-dominatedbeam The black points show the data the blue line shows the bestfit to the data
075 080 085 090 095 10015
20
25
30
35
40
90 CL68 CL
90 CL
sin2(2120579)
|Δm
2|(10minus3eV
2)
MINOS 3788 kt-yr atmospheric
336 times 1020 POT 120583 modeSuper-K zenith anglelowast
Super-K LElowast
T2Klowastlowast
lowastNeutrino 2012lowastlowastPRD 85 031103(R) (2012)
1071 times 1020 POT 120583 mode
Figure 12 The allowed regions for the atmospheric oscillationparameters |Δ1198982| and sin2(2120579) assuming identical neutrino andantineutrino oscillation parametersTheMINOS result is comparedto measurements from Super-Kamiokande [61] and T2K [62]
The data are fit to extract a measurement of 12057913 The
resulting measurement is shown in Figure 17 The measuredvalue of 120579
13depends on the CP violating phase 120575 which
directly affects the ]119890and ]
119890appearance probabilities and
themass hierarchy which affects the appearance probabilitiesthrough the interactions of the neutrinos with the matter in
MINOS 120583 disappearance1071 times 1020 POT 120583 mode336 times 1020 POT mode3788kt-yr atmospheric
90 CL120583120583120583 + 120583
120583120583120583 + 120583
Best fit
sin2(2120579) or sin2(2120579)
(|Δm
2|
or Δ
m2|)
(10minus3eV
2)
075 080 085 090 095 100
20
25
30
35
120583
|Figure 13 The allowed region for antineutrino oscillation param-eters (blue line) compared to the region measured with neutrinosalone (red line) and the region measured using both neutrinos andantineutrinos under the assumption they have the same parameters(black line)
20
25
30
20 25 30
|Δm
2| (10
minus3eV
2)
|Δm2| (10minus3eV2)
68 CL|Δm2| = |Δm2|
MINOS 120583 disappearance1071 times 1020 POT 120583 mode336 times 1020 POT mode3788kt-yr atmospheric
90 CLBest fit
120583
Figure 14 A comparison of the measured limits on the masssplittings of neutrinos and antineutrinos
the Earthrsquos crust Assuming a normal mass hierarchy 120575 = 0and 120579
23lt 1205874 MINOS measures 2sin2(2120579
13)sin2(120579
23) =
0051+0038
minus0030 Assuming an inverted mass hierarchy 120575 = 0
and 12057923
lt 1205874 MINOS measures 2sin2(212057913)sin2(120579
23) =
0093+0054
minus0049 This measurement is consistent with the results
from reactor neutrino searches [72ndash74] and the T2K experi-ment [75]
This MINOS measurement is the first ever search for ]119890
appearance in a long-baseline ]120583beam and the first search
Advances in High Energy Physics 11
Reconstructed energy (GeV)0 6 8
Frac
tion
of ev
ents
0
01
02
03
04
Standard MC
MINOS
2 4
Near detector 2011
NC120583-CCe-CC
(a)
Horn-off MC
Reconstructed energy (GeV)0 6 8
Frac
tion
of ev
ents
0
01
02
03
04 MINOS
2 4
Near detector 2011
NC120583-CCe-CC
(b)
High energy MC
Reconstructed energy (GeV)0 6 8
Frac
tion
of ev
ents
0
01
02
03
04 MINOS
2 4
Near detector 2011
NC120583-CCe-CC
(c)
Figure 15 The contribution of the three components to the background in the ]119890appearance search as simulated in the ND (a) the regular
(low energy) beam data (b) with no current in the NuMI focusing horns (c) a high energy beam configuration
for ]119890and ]119890appearance with significant matter effects Both
of these effects provide some sensitivity to the neutrinomass hierarchy and CP violation when the MINOS data iscompared to the measurements made by reactor neutrinosearches [72ndash74] (we have calculated a limit of sin2(2120579
13) =
0098 plusmn 0013 from the reactor data at the time of analysis)The sensitivity of MINOS to the mass hierarchy and CPviolation is modest but this contributes to the first analysisof the type that will be used by all future long-baselineexperiments The resulting values of the likelihood by whichMINOS disfavours various values of these parameters areshown in Figure 18 [76]
6 Search for Sterile Neutrino Mixing UsingNeutral-Current Interactions
The energy spectrum of NC interactions in the FD should beunchanged by standard neutrino oscillationThe existence ofone or more sterile neutrino flavours ]
119904 could cause a deficit
in the observed NC interaction rate As with all the MINOSoscillation analyses the energy spectrum of NC interactionsobserved in the ND (which was shown in Figure 8) is usedto predict the spectrum expected at the FD [77] The FDexpectation is shown in Figure 19 with the dashed blue linetaking into account ]
119890appearance corresponding to 120579
13=
115∘ (at the limit set by CHOOZ [78] and a little above
the current accepted value [29 72ndash75] this analysis usesonly the first 707 times 10
20 protons on target of data andwas performed before the recent positive measurements ofa nonzero 120579
13) The data are also shown in the figure and
are in good agreement with the expectation confirming thestandard model of neutrino oscillation This agreement canbe quantified using a test statistic 119877
119877 =119873data minus 119861CC
119878NC (7)
where 119873data is the number of events observed 119861CC is thepredicted background of CC interactions and 119878NC is the
predicted number of NC interactions A value of 119877 = 101 plusmn
006(stat) plusmn 005(syst) is obtained (over the full energy range0ndash120GeV) which is in good agreement with the expectationof 119877 = 1 in the case of no mixing with sterile neutrinos
The data are analysed with a model that assumes a singlesterile neutrino flavour mixing through the addition of afourth neutrino mass state119898
4≫ 1198983 This introduces a mass
splitting Δ119898243
with magnitude O(1 eV2) such that no oscil-lation-induced change to the event rate is observed at theND and the oscillatory energy dependence of the induceddepletion at the FD is so rapid that an overall uniform deple-tion is observed once the energy resolution of the detectors isaccounted forThismodel introduces three additionalmixingangles 120579
14 12057924 and 120579
34 MINOS is insensitive to 120579
14but sets
limits of 12057924= (00
+5
minus00)∘ and 120579
34= (00
+25
minus00)∘ These limits are
evaluated assuming 12057913at the CHOOZ limit
The limit on the coupling of sterile to active neutrinos canbe quantified by defining 119891
119904 the fraction of disappearing ]
120583
which have oscillated into ]119904
119891119904=
119875]120583rarr ]119904
1 minus 119875]120583rarr ]120583
(8)
For the model used in which 1198984≫ 119898
3 119891119904is evaluated
at 14 GeV the energy of maximal ]120583disappearance To
determine the limit on 119891119904 a large number of test values
are chosen of the mixing angles 12057924 12057934 and 120579
23 from
Gaussian distributions according to the measured values and1120590 uncertainties given above (with 120579
23constrained from the
measurements with CC ]120583interactions) 119891
119904is calculated for
each case and the value of 119891119904that is larger than 90 of the
test cases represents the limit MINOS limits 119891119904lt 040 at the
90 confidence level
7 The Future MINOS+
The MINOS experiment has made some very importantcontributions to our understanding of neutrino oscillation
12 Advances in High Energy Physics
Reconstructed energy (GeV)
Reconstructed energy (GeV)
Even
ts
30
0
10
20
Even
ts
30
0
10
20
Even
ts
30
0
10
20
2 4 6 8
2 4 6 8
Reconstructed energy (GeV)2 4 6 8
06 lt 120572LEM lt 07
MINOS far detector data
07 lt 120572LEM lt 08
120572LEM gt 08
mode
mode
mode
e CC signal
e CC signalBackgroundData
(a)
Even
ts
Reconstructed energy (GeV)2 4 6 8
Reconstructed energy (GeV)2 4 6 8
Reconstructed energy (GeV)2 4 6 8
06 lt 120572LEM lt 07
MINOS far detector data
Merged for fit
07 lt 120572LEM lt 08
120572LEM gt 08
mode
mode
mode
8
6
4
2
0
Even
ts
8
6
4
2
0
Even
ts
8
6
4
2
0
e CC signal
e CC signalBackgroundData
5ndash8GeV bins
(b)
Figure 16 The CC ]119890(a) and ]
119890(b) candidate events selected in the FD compared to the expectation without any ]
119890appearance (red) and
with the best fit for 12057913(purple) The events are divided into bins of the library event matching discriminant variable
Advances in High Energy Physics 13
20
15
10
05
000 01 02 03 04
2sin2(212057913)sin212057923
Δm2 gt 0
sin
120575(120587)
(a)
20
15
10
05
000 01 02 03 04
2sin2(212057913)sin212057923
MINOS best fit 12057923 lt 1205874
MINOS best fit 12057923 gt 1205874
Δm2 lt 0
MINOS
106 times 1020 POT -mode33 times 1020 POT -mode
68 CL 12057923 lt 1205874
90 CL 12057923 lt 1205874
120575(120587)
(b)
Figure 17 The allowed regions for 2sin2(212057913)sin2(120579
23)
120575(120587)
Δm2 gt 0 12057923 gt 1205874
Δm2 gt 0 12057923 lt 1205874
Δm2 lt 0 12057923 gt 1205874Δm2 lt 0 12057923 lt 1205874
3
2
1
00 1 1505 2
MINOS
90 CL
68 CL
minus2Δ
(L)
ln
Figure 18 The values of likelihood 119871 by which various values oftheCP violating parameter 120575 the mass hierarchy and the octant of12057923are disfavouredThis analysis uses MINOS data and information
from reactor neutrino measurements of 12057913[72ndash74]
physics and has finished taking data with the low energybeam for which it was designed However the experimentwill continue taking data and producing new results for thenext few years as MINOS+ [79] The NuMI beam is being
20
2018161410 12
Far detector data
Even
ts (G
eV)
00 2 4 6 8
40
60
80
100
120
140
12057913 = 0∘
12057913 = 115∘ 120575 = 120587 Δm232 gt 0
120583 CC background|Δm2
32| = 232 times 10minus3eV2
Ereco (GeV)
sin2212057923 = 1
Figure 19 The black dots show the energy spectrum of NCinteractions observed in the far detector The red lines show theexpectation in the case of no sterile neutrinos and 120579
13= 0 the blue
dashed line shows the same expectation with 12057913= 115
∘
upgraded to a higher energy and intensity for the NO]Aexperiment the far detector of which will sit 14 mrad offaxisNO]A will receive a narrow-band beam peaking at around2GeV which is ideal for searching for ]
119890appearance since
the background seen in MINOS from NC interactions ofhigh energy neutrinos will be heavily reduced Figure 20shows that the MINOS FD will see an intense ]
120583beam
14 Advances in High Energy Physics
1000
500
00 5 10 15 20
E (GeV)
MINOS+NOAMINOS
Preliminary
Simulated beam54 kton 6 times 1020 POT
120583CC
even
ts (G
eV)
Figure 20 The ]120583energy spectrum that will be observed by the
MINOS+ FD compared to the spectra observed by MINOS andNO]A
peaking at around 7GeV In this configuration MINOS+ willobserve around 4000 CC ]
120583interactions in the FD each
year unprecedented statistics for a long-baseline oscillationexperimentThis will offer a unique high precision test of thethree-flavour oscillation paradigm
MINOS+ will be able to make a very sensitive searchfor the sterile neutrinos suggested by the LSND [80] andMiniBooNE [81 82] data and by some interpretations ofreactor neutrino data [83] This search will cover more thanthree orders of magnitude in the mass splitting between thesterile and active neutrinos The signal that MINOS+ willsearch for is illustrated in Figure 21 Figure 21(a) illustratesthe increase in statistical precision thatMINOS+will provideon the ratio of the observed CC ]
120583interaction rate to
that expected without oscillations Figure 21(b) shows howthis ratio is modified if a sterile neutrino exists and mixeswith the active neutrinos an additional deficit of muonneutrino interactions occurs in the higher energy region ofthe spectrum In the model assumed here which introducesa single sterile neutrino state three new mixing angles areintroduced 120579
14 12057924 and 120579
34 An additional mass splitting
Δ1198982
43is also introduced The position in energy of the
additional deficit is governed by the value of the new masssplittingThemagnitude of the additional deficit in the CC ]
120583
interaction rate is governed primarily by the size of 12057924 this is
in comparison to short-baseline searches for ]119890disappearance
from reactors which are governed by 12057914and searches for ]
119890
appearance in ]120583beamswhich are governed by a combination
of 12057914
and 12057924 A detailed explanation of the global effort to
search for sterile neutrinos can be found in [84]The sensitivity of the MINOS+ experiment when com-
bined with the Bugey reactor neutrino data [85] is shown in
MINOS+ simulation
MINOS 1071 times 1021 POT06 times 1021 POT12 times 1021 POT18 times 1021 POT
120583su
rviv
al p
roba
bilit
y
Neutrino energy (GeV)0 5 10 15
15
1
05
0
(a)
P(
120583rarr
120583)
No sterile neutrinosΔm2
43 = 2 times 10minus2eV2 sin2(212057924) = 02
0 5 10 15 20
1
0
18
06
04
02
Neutrino energy (GeV)
(b)
Figure 21 (a) The black points show the ratio of the observed ]120583
energy spectrum to the expectation in the case of no oscillation inthe neutrino-dominated beam of MINOS The blue region showsthe statistical precision expected from MINOS+ (b) The black lineshows the muon neutrino survival probability in the case of nosterile neutrinos the red line shows how the probability would bemodified by the addition of mixing with a sterile neutrino
Figure 22 MINOS+ has the potential to rule out much of theLSND allowed region MINOS+ will begin taking data in thelate summer of 2013 and will continue taking data for at leasttwo years (Figure 22 assumes two years of data taking with aneutrino-dominated beam)
8 Conclusion
The MINOS experiment was conceived at a time when neu-trino oscillation had only recently been confirmed as thesolution to the problem of neutrino flavour change It has
Advances in High Energy Physics 15
Δm
2
10minus210minus2
10minus1
10minus1
10minus310minus4 1
1
10
102
LSND 90 CLLSND 99 CLKarmen2 90 CLBugey 90 CLlowast
MiniBooNE 90 CLMiniBooNE 99 CLMINOS+ and Bugeycombination 90 CL
sin22120579120583e
lowastGLoBES 2012 fit with new reactor fluxescourtesy of P Huber
Figure 22 The sensitivity of MINOS+ to the existence of sterileneutrinos when combined with data from the Bugey [85] reactorneutrino experiment Δ1198982 is the splitting between the three knownneutrino mass states and a new fourth state 120579
120583119890is the mixing angle
governing ]120583rarr ]119890transitions when a fourth sterile neutrino state
is introduced into the PMNSmixingmatrixThis figure assumes twoyears of MINOS+ running with a neutrino-dominated beam
played a hugely influential role in bringing neutrino oscilla-tion physics into an era of precision measurement MINOSrsquosmeasurement of the largest neutrino mass splitting is themost precise in the world MINOS has made the first directprecision measurement of the corresponding antineutrinoparameters a measurement that promises to remain theworldrsquos most precise for many years And MINOS has playeda role in the discovery of a nonzero value for 120579
13
Now that the value of 12057913is known the neutrino physics
community can move on to determine the neutrino masshierarchy and to search for CP violation in the neutrinosector MINOS has pioneered a number of techniques thatwill be used by future experiments The two-detector setupall important in reducing the impact of systematic uncer-tainties is the design of choice for any new experiment andMINOS has demonstrated methods of using a near detectorto determine the expectation at a far detector MINOS hasperformed the first search for ]
119890appearance in a ]
120583beam
and the first search for ]119890and ]119890appearance with significant
matter effects demonstrating the analysis techniques that willbe used to determine the mass hierarchy and CP violationparameter
In the second half of 2013 MINOS will begin taking dataas the MINOS+ experiment which will make ever more pre-cise tests of the three-flavour neutrino oscillation paradigmand set world-leading limits on the existence of sterileneutrinos This is an exciting future for an experiment thatwith a decade of data taking so far has already created alasting legacy for itself in our understanding of the neutrino
A comparison of themeasured neutrino and antineutrinomass splittings is shown in Figure 14 the difference betweenthe two is constrained to |Δ119898
2| minus |Δ119898
2| = (012
+024
minus026) times
10minus3 eV2
Acknowledgment
The work of the MINOS and MINOS+ collaborations issupported by the US DoE the UK STFC the US NSF theState and University of Minnesota the University of Athensin Greece and Brazilrsquos FAPESP and CNPq The authors aregrateful to the Minnesota Department of Natural Resourcesthe crew of the Soudan Underground Laboratory and thepersonnel of Fermilab for their vital contributions
References
[1] S Wojcicki ldquoLong baseline neutrino oscillation programe inthe United Statesrdquo Nuclear Physics B vol 77 no 1ndash3 pp 182ndash186 1999 Proceedings of the 18th International Conference onNeutrino Physics and Astrophysics (Neutrino rsquo98) TakayamaJapan June 1998
[2] R Davis Jr D S Harmer and K C Hoffman ldquoSearch forneutrinos from the sunrdquo Physical Review Letters vol 20 no 21pp 1205ndash1209 1968
[3] A I Abazov O L Anosov E L Faizov et al ldquoSearch forneutrinos from sun using the reactionGa-71 (electron-neutrinoe-) Ge-71rdquo Physical Review Letters vol 67 pp 3332ndash3335 1991
[4] P Anselmann W Hampel G Heusser et al ldquoSolar neutrinosobserved by GALLEX at gran sassordquo Physics Letters B vol 285no 4 pp 376ndash389 1992
[5] M Aglietta G Battistoni E Bellotti et al ldquoExperimentalstudy of atmospheric neutrino flux in the NUSEX experimentrdquoEurophysics Letters vol 8 no 7 article 611 1989
[6] K S Hirata ldquoObservation of a small atmospheric V120583V119890ratio in
Kamiokanderdquo Physics Letters B vol 280 no 1-2 pp 146ndash1521992
[7] R Becker-Szendy C B Bratton D Casper et al ldquoElectron-and muon-neutrino content of the atmospheric fluxrdquo PhysicalReview D vol 46 pp 3720ndash3724 1992
[8] K Daum W Rhode P Bareyre et al ldquoDetermination ofthe atmospheric neutrino spectra with the frejus detectorrdquoZeitschrift fur Physik C vol 66 no 3 pp 417ndash428 1995
[9] S Ahlen M Ambrosio R Antolini and G Auriemma ldquoAtmo-spheric neutrino flux measurement using upgoing muonsrdquoPhysics Letters B vol 357 no 3 pp 481ndash486 1995
[10] WMAllison G J Alner D S Ayres et al ldquoMeasurement of theatmospheric neutrino flavour composition in Soudan 2rdquoPhysicsLetters B vol 391 no 3-4 pp 491ndash500 1997
16 Advances in High Energy Physics
[11] Y Fukuda T Hayakawa E Ichihara et al ldquoEvidence foroscillation of atmospheric neutrinosrdquo Physical Review Lettersvol 81 no 8 pp 1562ndash1567 1998
[12] Q R Ahmad R C Allen T C Andersen et al ldquoMeasurementof charged current interactions produced by solar neutrinos atthe sudbury neutrino observatoryrdquo Physical Review Letters vol87 Article ID 071301 2001
[13] Q R Ahmad R C Allen T C Andersen et al ldquoDirect evidencefor neutrino flavor transformation from neutral-current inter-actions in the sudbury neutrino observatoryrdquo Physical ReviewLetters vol 89 Article ID 011301 6 pages 2002
[14] B Pontecorvo ldquoInverse beta processes and nonconservation oflepton chargerdquo Journal of Experimental and Theoretical Physicsvol 34 pp 172ndash173 1958
[15] V N Gribov and B Pontecorvo ldquoNeutrino astronomy andlepton chargerdquo Physics Letters B vol 28 pp 493ndash496 1969
[16] Z Maki M Nakagawa and S Sakata ldquoRemarks on the unifiedmodel of elementary particlesrdquo Progress of Theoretical Physicsvol 28 no 5 pp 870ndash880 1962
[17] P Adamson C Andreopoulos D J Auty et al ldquoFirst directobservation of muon antineutrino disappearancerdquo PhysicalReview Letters vol 107 no 2 Article ID 021801 2011
[18] P Adamson D J Auty D S Ayres et al ldquoSearch for thedisappearance of muon antineutrinos in the NuMI neutrinobeamrdquo Physical Review D vol 84 no 7 Article ID 071103 6pages 2011
[19] P Adamson D S Ayres C Backhouse et al ldquoImprovedmeasurement of muon antineutrino disappearance inMINOSrdquoPhysical Review Letters vol 108 no 19 Article ID 191801 5pages 2012
[20] P Adamson I Anghel C Backhouse et al ldquoMeasurementof Neutrino and Antineutrino Oscillations Using Beam andAtmospheric Data in MINOSrdquo Physical Review Letters vol 110no 25 Article ID 251801 6 pages 2013
[21] K Anderson B Bernstein D Boehnlein et al ldquoThe NuMIFacility Technical Design Reportrdquo FERMILAB-DESIGN-1998-01 1998
[22] D G Michael P Adamson T Alexopoulos et al ldquoObservationof muon neutrino disappearance with the MINOS detectors inthe NuMI neutrino beamrdquo Physical Review Letters vol 97 no19 Article ID 191801 6 pages 2006
[23] P Adamson C Andreopoulos K E Arms et al ldquoStudy ofmuon neutrino disappearance using the fermilab main injectorneutrino beamrdquo Physical Review D vol 77 no 7 Article ID072002 34 pages 2008
[24] P Adamson C Andreopoulos K E Arms et al ldquoMeasurementof neutrino oscillations with theMINOS detectors in the NuMIbeamrdquo Physical Review Letters vol 101 no 13 Article ID 1318025 pages 2008
[25] P Adamson C Andreopoulos R Armstrong et al ldquoMea-surement of the neutrino mass splitting and flavor mixing byMINOSrdquo Physical Review Letters vol 106 no 18 Article ID181801 6 pages 2011
[26] P Adamson C Andreopoulos K E Arms et al ldquoSearch formuon-neutrino to electron-neutrino transitions in MINOSrdquoPhysical Review Letters vol 103 no 26 Article ID 261802 5pages 2009
[27] PAdamsonCAndreopoulosD J Auty et al ldquoNew constraintsonmuon-neutrino to electron-neutrino transitions inMINOSrdquoPhysical ReviewD vol 82 no 5 Article ID 051102 6 pages 2010
[28] P Adamson D J Auty D S Ayres et al ldquoImproved search formuon-neutrino to electron-neutrino oscillations in MINOSrdquoPhysical Review Letters vol 107 no 18 Article ID 181802 6pages 2011
[29] P Adamson I Anghel C Backhouse et al ldquoElectron neutrinoand antineutrino appearance in the full MINOS data samplerdquoPhysical Review Letters vol 110 no 17 Article ID 171801 6 pages2013
[30] P Adamson C Andreopoulos K E Arms et al ldquoSearch foractive neutrino disappearance using neutral-current interac-tions in theMINOS long-baseline experimentrdquo Physical ReviewLetters vol 101 no 22 Article ID 221804 5 pages 2008
[31] P Adamson C Andreopoulos D J Auty et al ldquoSearch for ster-ile neutrino mixing in the MINOS long-baseline experimentrdquoPhysical Review D vol 81 no 5 Article ID 052004 18 pages2010
[32] P Adamson D J Auty D S Ayres et al ldquoActive to sterileneutrino mixing limits from neutral-current interactions inMINOSrdquo Physical Review Letters vol 107 no 1 Article ID011802 5 pages 2011
[33] Z Pavlovic Observation of disappearance of muon neutrinos inthe NuMI beam [PhD thesis] University of Texas at AustinAustin Tex USA 2008
[34] F Ballarini G Battistoni M Campanella et al ldquoThe FLUKAcode an overviewrdquo Journal of Physics vol 41 article 151 2006
[35] S Agostinelli J Allison K Amako et al ldquoGEANT4mdasha sim-ulation toolkitrdquo Nuclear Instruments and Methods in PhysicsResearch A vol 506 no 3 pp 250ndash303 2003
[36] G Battistoni F Cerutti A Fasso et al ldquoThe FLUKA codedescription and benchmarkingrdquo in Proceedings of the HadronicShower Simulation Workshop vol 896 of AIP Conference Pro-ceedings pp 31ndash49 Batavia Ill USA September 2006
[37] D G Michaele P Adamson T Alexopoulos et al ldquoThe mag-netized steel and scintillator calorimeters of the MINOS exper-imentrdquoNuclear Instruments and Methods in Physics Research Avol 596 no 2 pp 190ndash228 2008
[38] I E Stockdale A Bodek F Borcherding N Giokaris et alldquoLimits on muon-neutrino oscillations in the mass range 30 lt9987791198982lt 1000 eV2c4 rdquo Physical Review Letters vol 52 no 16 pp
1384ndash1388 1984[39] F Dydak G J Feldman C Guyot et al ldquoA search for V
120583
oscillations in the9987791198982 range 03ndash90 eV2 rdquo Physics Letters B vol134 no 3-4 pp 281ndash286 1984
[40] F Bergsma J Dorenbosch M Jonker et al ldquoA searchfor oscillations of muon neutrinos in an experiment withLEcong07 kmGeVrdquo Physics Letters B vol 142 no 1-2 pp 103ndash1101984
[41] M H Ahn E Aliu S Andringa et al ldquoMeasurement ofneutrino oscillation by the K2K experimentrdquo Physical ReviewD vol 74 no 7 Article ID 072003 39 pages 2006
[42] P Adamson T Alexopoulos W W M Allison et al ldquoFirstobservations of separated atmospheric V
120583and ]
120583events in the
MINOS detectorrdquo Physical Review D vol 73 no 7 Article ID072002 2006
[43] P Adamson C Andreopoulos K E Arms et al ldquoCharge-separated atmospheric neutrino-inducedmuons in theMINOSfar detectorrdquo Physical ReviewD vol 75 no 9 Article ID 09200314 pages 2007
[44] P Adamson C Backhouse G Barr et al ldquoMeasurements ofatmospheric neutrinos and antineutrinos in the MINOS fardetectorrdquo Physical Review D vol 86 no 5 Article ID 05200720 pages 2012
Advances in High Energy Physics 17
[45] M A Kordosky Hadronic interactions in the MINOS detectors[PhD thesis] University of Texas at Austin Austin Tex USA2004
[46] P L Vahle Electromagnetic interactions in the MINOS detectors[PhD thesis] University of Texas at Austin Austin Tex USA2004
[47] C Backhouse Measuring neutrino oscillation parameters using]120583disappearance inMINOS [PhD thesis] University of Oxford
Oxford UK 2011[48] T M Cover and P E Hart ldquoNearest neighbor pattern classifi-
cationrdquo IEEE Transactions on Information Theory vol 13 no 1pp 21ndash27 1967
[49] R Ospanov A measurement of muon neutrino disappearancewith the MINOS detectors and NuMI beam [PhD thesis]University of Texas at Austin Austin Tex USA 2008
[50] J S Marshall A study of muon neutrino disappearance with theMINOS detectors and the NuMI neutrino beam [PhD thesis]University of Cambridge Cambridge UK 2008
[51] J P OchoaA search formuon neutrino to electron neutrino oscil-lations in the MINOS Experiment [PhD thesis] The CaliforniaInstitute of Technology Pasadena Calif USA 2009
[52] R TonerMeasuring 12057913via muon neutrino to electron neutrino
oscillations in the MINOS experiment [PhD thesis] Universityof Cambridge Cambridge UK 2011
[53] A Holin Electron neutrino appearance in the MINOS experi-ment [PhD thesis] University College London London UK2010
[54] J Boehm Measurement of electron neutrino appearance withthe MINOS experiment [PhD thesis] Harvard UniversityCambridge Mass USA 2009
[55] G Tinti Sterile neutrino oscillations in MINOS and hadronproduction in pC collisions [PhD thesis] University of OxfordOxford UK 2010
[56] J J EvansMeasuring antineutrino oscillations with the MINOSexperiment [PhD thesis] University of Oxford Oxford UK2008
[57] S J ColemanAmeasurement of neutrino oscillations withmuonneutrinos in the MINOS experiment [PhD thesis] College ofWilliam ampMary Williamsburg Va USA 2011
[58] J S Mitchell Measuring ]120583disappearance with the MINOS
experiment [PhD thesis] University of Cambridge CambridgeUK 2011
[59] A McGowan Observation of deficit in NuMI neutrino-inducedrock and non-fiducial muons in MINOS far detector andmeasurement of neutrino oscillation parameters [PhD thesis]University of Minnesota Minneapolis Minn USA 2007
[60] M StraitMeasurement of neutrino oscillation parameters usinganti-fiducial charged current events in MINOS [PhD thesis]University of Minnesota Minneapolis Minn USA 2010
[61] Y Itow ldquoAtmospheric neutrinosmdashresults from running exper-imentsrdquo in Proceedings of the 25th International Conference onNeutrino Physics and Astrophysics (Neutrino rsquo12) Kyoto JapanJune 2012
[62] K Abe N Abgrall Y Ajima et al ldquoFirst muon-neutrinodisappearance study with an off-axis beamrdquo Physical Review Dvol 85 no 3 Article ID 031103 8 pages 2012
[63] K Nakamura ldquoReview of particle physicsrdquo Journal of Physics Gvol 37 Article ID 075021 2010
[64] L Wolfenstein ldquoNeutrino oscillations in matterrdquo PhysicalReview D vol 17 no 9 pp 2369ndash2374 1978
[65] J W F Valle ldquoResonant oscillations of massless neutrinos inmatterrdquo Physics Letters B vol 199 no 3 pp 432ndash436 1987
[66] M C Gonzalez-Garcia M M Guzzo P I Krastev et alldquoAtmospheric neutrino observations and flavor changing inter-actionsrdquo Physical Review Letters vol 82 no 16 pp 3202ndash32051999
[67] A Friedland C Lunardini and M Maltoni ldquoAtmosphericneutrinos as probes of neutrino-matter interactionsrdquo PhysicalReview D vol 70 no 11 Article ID 111301 2004
[68] Z IsvanAntineutrino oscillations and a Search for non-standardInteractions with the MINOS [PhD thesis] University of Pitts-burgh Pittsburgh Pa USA 2012
[69] W A Mann D Cherdack W Musial and T Kafka ldquoApparentmultiple 998779119898
32
2 in ]120583and V
120583survival oscillations from nonstan-
dard interactionmatter effectrdquo Physical Review D vol 82 no 11Article ID 113010 8 pages 2010
[70] J Kopp P A N Machado and S J Parke ldquoInterpretation ofMINOS data in terms of nonstandard neutrino interactionsrdquoPhysical Review D vol 82 no 11 Article ID 113002 12 pages2010
[71] J A B Coelho Investigacao de mecanismos alternativos aoscilacao de neutrinos no experimentos MINOS [PhD thesis]Universidade Estadual de Campinas Sao Paulo Brazil 2012
[72] F P An Q An J Z Bai A B Balantekin et al ldquoImprovedmeasurement of electron antineutrino disappearance at DayaBayrdquo Chinese Physics C vol 37 Article ID 011001 21 pages 2013
[73] J K Ahn S Chebotaryov J H Choi et al ldquoObservationof reactor electron antineutrinos disappearance in the RENOexperimentrdquo Physical Review Letters vol 108 Article ID 1918026 pages 2012
[74] Y Abe C Aberle J C dos Anjos et al ldquoReactor electronantineutrino disappearance in the Double Chooz experimentrdquoPhysical Review D vol 86 Article ID 052008 2012
[75] K Abe N Abgrall H Aihara et al ldquoEvidence of electronneutrino appearance in a muon neutrino beamrdquo PhysicalReview D vol 88 no 3 Article ID 032002 41 pages 2013
[76] A Schreckenberger Electron neutrino and antineutrino appear-ance in the MINOS detector [PhD thesis] University of Min-nesota Minneapolis Minn USA 2013
[77] D J Koskinen MINOS sterile neutrino search [PhD thesis]University College London London UK 2009
[78] M Apollonio A Baldini C Bemporad et al ldquoSearch forneutrino oscillations on a long base-line at the CHOOZ nuclearpower stationrdquoTheEuropean Physical Journal C vol 27 pp 331ndash374 2003
[79] G Tzanankos M Bishai M Diwan et alMINOS+ a proposalto FNAL to run MINOS with the medium energy NuMI beam[PhD thesis] University of Athens Athens Greece 2011
[80] A Aguilar L B Auerbach R L Burman et al ldquoEvidence forneutrino oscillations from the observation of ]
119890e appearance
in a ]120583beamrdquo Physical Review D vol 64 Article ID 112007 22
pages 2001[81] A A Aguilar-Arevalo C E Anderson S J Brice et al ldquoSearch
for electron antineutrino appearance at the Δ119898 sim 1 eV2 ScalerdquoPhysical Review Letters vol 103 no 11 Article ID 111801 2009
[82] A A Aguilar-Arevalo C E Anderson A O Bazarko et alldquoImproved search for V
120583rarr V119890oscillations in the MiniBooNE
experimentrdquo Physical Review Letter vol 110 no 10 Article ID161801 2013
[83] GMentionM Fechner T Lasserre et al ldquoReactor antineutrinoanomalyrdquo Physical Review D vol 83 Article ID 073006 20pages 2011
18 Advances in High Energy Physics
[84] KNAbazajianMAAcero S KAgarwalla et al ldquoLight sterileneutrinos a white paperrdquo httparxivorgabs12045379
[85] B Achkar R Aleksan M Avenier et al ldquoSearch for neutrinooscillations at 15 40 and 95meters from a nuclear power reactorat Bugeyrdquo Nuclear Physics B vol 434 no 3 pp 503ndash532 1995
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
High Energy PhysicsAdvances in
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
FluidsJournal of
Atomic and Molecular Physics
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in Condensed Matter Physics
OpticsInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
AstronomyAdvances in
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Superconductivity
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Statistical MechanicsInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
GravityJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
AstrophysicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Physics Research International
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Solid State PhysicsJournal of
Computational Methods in Physics
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Soft MatterJournal of
Hindawi Publishing Corporationhttpwwwhindawicom
AerodynamicsJournal of
Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
PhotonicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Biophysics
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
ThermodynamicsJournal of
4 Advances in High Energy Physics
PMT assembly
CookieMUX box optical
connectorOptical cable
MUX box
Optical connector
WLS fibers
Scintillator strips
Steel plates
Figure 4 A MINOS detector plane
The MINOS Far Detector is also a very effective detectorof neutrinos produced in the atmosphere Since it wasswitched on in 2003 it has recorded 379 kton-years of datarecording 2072 candidate neutrino interactions that havebeen included into the analyses of the beam data to improvethe precision of the oscillation parameter measurements [2042ndash44]
3 Neutrino Interactions inthe MINOS Detectors
Three types of neutrino interaction shown in Figure 5 areof interest to MINOS Muon neutrinos and antineutrinosinteract through the CC process
]120583(]120583) + 119883 997888rarr 120583
minus(+)+ 1198831015840 (3)
The cascade of hadrons 1198831015840 produces a diffuse shower ofenergy deposits near the interaction vertex The muon pro-duces a long track that curves in the magnetic field thedirection of curvature identifying the incoming neutrino asa ]120583or a ]120583
All active neutrino flavours undergo NC interactionsthrough the process
] + 119883 997888rarr ] + 1198831015840 (4)
Only the hadronic cascade is observed producing a diffuseshower of energy deposits
Finally electron neutrinos undergo CC interactionsthrough the process
]119890+ 119883 997888rarr 119890
minus+ 1198831015840 (5)
The electron gives rise to an electromagnetic shower whichproduces a much denser more compact shower of energydeposits
The energy of the neutrino is determined by summing theenergies of the shower and anymuon trackThemuon energyis determined from the length of stopping tracks leading toa resolution of around 5 and from the curvature in themagnetic field for tracks that exit the detector leading to aresolution of around 10 For NC and ]
119890CC interactions
the energy of the shower is determined through calorimetryThe calorimetric energy resolution for hadronic showers isaround 55radicenergy [45] and for electromagnetic showers20radicenergy [46] For ]120583 CC interactions a more sophisti-cated approach is used to improve the resolution of hadronicshower energy measurement [47] For low energy showers(of a few GeV or below) significant additional information isheld in the topology of the showerThree event characteristicsare used the calorimetric energy deposit within 1m of theinteraction vertex the sum of the calorimetric energy in thetwo largest showers in the event and the physical length ofthe largest shower These variables are input into a 119896-nearest-neighbour algorithm [48] which finds the best matches froma library of simulated events and uses these to estimate thehadronic energyThis improves the shower energy resolutionfrom 55 to 43 for showers between 10GeV and 15 GeV
31 Selection of Charged-Current ]120583and ]
120583Interactions To
make a measurement of 119875(]120583
rarr ]120583) it is necessary to
select a pure sample of ]120583CC interactions This is achieved
by selecting events with a clear muon track The main loss inefficiency comes from events with a high inelasticity in whicha short muon track is hidden in a large hadronic cascade
Advances in High Energy Physics 5
CC 120583 event
120583minus
15
1
05
0
0
05 1 15 2 25 3 35 4
Longitudinal position (m)
Tran
sver
se p
ositi
on (m
)
minus05
(a)
V
06
04
02
0
minus02
minus02
minus04
minus04
minus06
0 02 04 06 08 1
NC event
Longitudinal position (m)
Tran
sver
se p
ositi
on (m
)
(b)
e
02
0
02
0 05 1
CC e event
Longitudinal position (m)
Tran
sver
se p
ositi
on (m
)
lowast
(c)
Figure 5 Neutrino interaction topologies observed in the MINOS detectors (a) A CC ]120583interaction (b) A NC interaction (c) A CC ]
119890
interaction Each coloured rectangle represents an excited scintillator strip the colour indicating the amount of light purple and blue are lowlight levels through to orange and red for the highest light levels
The main background occurs at low energies and consists ofsmall cascades from NC interactions in which a low energyhadron such as a proton or a charged pion exhibits a track-like topology that mimics a low energy muon Four variablesare constructed that discriminate between muons trackswhich are typically long and show a constant energy deposi-tion along the length and spurious hadronic tracks which aretypically shorter and show greater fluctuations in the energydeposition These variables are the event length the averageenergy deposited per scintillator plane along the track thetransverse energy deposition profile and the fluctuation of
the energy deposition along the track These variables areinput into a 119896-nearest-neighbour algorithm which calculatesa single discrimination variable shown in Figure 6 [49]Events for which this variable is greater than 03 are selectedas CC ]
120583interactions yielding a sample with a total efficiency
of 90 below 2GeV the NC contamination is 65 Theefficiency and contamination are energy dependent this fullenergy dependence is shown in Figure 6
The CC interactions of ]120583and ]
120583result in very similar
topologies the 119896-nearest-neighbour discriminant is thereforeused in the same way in both the neutrino-dominated and
6 Advances in High Energy Physics
CCNC separation parameter
Low energy beamDataMC expectation
NC background
Even
ts10
16PO
T
10
1
10minus1
10minus2
0 02 04 06 08 1
(a)
Reconstructed neutrino energy (GeV)
0
02
04
06
08
1
NC contamination
Far detector fiducial onlyCC selection efficiency
0 2 4 6 8 10
Effici
ency
con
tam
inat
ion
(b)
Figure 6 (a) The discrimination variable used to separate ]120583CC interactions from hadronic backgrounds Events with a parameter value
greater than 03 are selected as ]120583CC interactions (b) The efficiency and background contamination of the selected ]
120583CC sample in the far
detector
antineutrino-enhanced beams When performing a directmeasurement of the antineutrino oscillation parameters anadditional selection cut is made requiring the charge of themuon track to be positiveThis uses the direction of curvatureof themuon asmeasured by aKalman Filter algorithm [50] Afurther sample of ]
120583CC interactions is obtained from the 7
]120583component in the neutrino-dominated beamThis sample
contains a significant background of ]120583events in which a 120583minus
has been identified with the incorrect charge often at lowenergies where the muon undergoes significant scatteringTherefore a much stricter set of selection criteria are appliedto purify this ]
120583sample [18]
32 Selection of Charged-Current ]119890Interactions The selec-
tion of ]119890CC interactions focuses on identifying the dense
showers from the electromagnetic interaction of the electronrather than the much more diffuse hadronic showers Theprimary background comes from purely hadronic showerswhich can have a denser than average energy depositparticularly in the presence of a neutral pion decaying tophotons Once a set of shower-like events in the signalregion of 1ndash8GeV has been obtained a pattern matchingapproach called library event matching is used to identifythe interactions most likely to be ]
119890CC [51 52] Each event
in the data is compared to a library of 5 times 107 simulated
signal and background events its similarity to the libraryevents is quantified by comparing the pattern of energydeposits in each scintillator strip excited by the shower wherethe energy deposit is quantified by the charge recorded onthe photomultiplier tube For an arbitrary energy depositthe mean expected charge on a photomultiplier tube willbe some value 120582 The probability of observing an amountof charge 119899 is then a Poisson distribution 119875(119899 | 120582) Thelikelihood L of a data event corresponding to the same
physical shower topology as a simulated library event cantherefore be calculated as
logL =
119873strips
sum
119894=1
log [intinfin
0
119875 (119899119894
data | 120582) 119875 (119899119894
lib | 120582) d120582] (6)
where 119894 represents the 119894th scintillator strip in the showerUsing this definition of the likelihood the 50 library eventsare identified that best match the data eventThree quantitiesare calculated from this set of 50 best-matching library eventsthe fraction of the events that are true ]
119890CC events the
average inelasticity of the true ]119890CC events and the average
fraction of charge that overlaps between the data event andeach ]
119890CC library event These three quantities are input to
a neural network which calculates a classification variableshown in Figure 7 Events with a classification variable valueabove 06 are selected for analysis this value was chosen tomaximise the sensitivity to ]
119890and ]119890appearance
The efficiency of the ]119890CC selection is estimated from
the data rather than relying totally on the simulation Toobtain a pure sample of true hadronic showers a sampleof well-identified ]
120583CC events is selected and the energy
depositions corresponding to the muon track are removed[53]The simulated energy depositions of an electron are theninserted [54] providing a realistic sample of ]
119890CC events
Using thismethod the ]119890CC identification efficiency is found
to be (574 plusmn 28) in the neutrino-dominated beam and(633 plusmn 31) in the antineutrino-enhanced beam
33 Selection of Neutral-Current Interactions The signal of anNC interaction is a diffuse hadronic shower ]
120583CC interac-
tions also produce hadronic showers and if the inelasticityis high the tell-tale muon track may not visibly extend pastthe shower To purify a sample of NC interactions a simple
Advances in High Energy Physics 7
sin2(212057913) = 01
Δm232 gt 0 120575cp = 0 12057923 =
120587
4
Background
MINOS far detector80
60
40
20
00 01 02 03 04 05 06 07 08 09 1
LEM discriminant
Signal times10
Even
ts8
2times10
20PO
T
(a)
LEM discriminant
Even
ts10
19PO
T
DataMonte Carlo
MINOS near detector8000
6000
4000
2000
00 01 02 03 04 05 06 07 08 09 1
(b)
Figure 7 (a) The library event matching discriminant showing the expected distribution for background and CC ]119890signal events in the far
detector in the neutrino-dominated beam Note that the signal simulated for sin2(212057913) = 01 120575 = 0 and a normal mass hierarchy has been
scaled up by a factor of ten for visibility (b)The same discriminant as observed in the near detector compared with the simulated expectation
Near detector dataMonte Carlo prediction
20
10
30
50
2018161410 120
0 2 4 6 8
40
60
120583 CC background
Ereco (GeV)
104
even
ts (G
eV)
Figure 8 The sample of events identified as NC interactions in thenear detector
cut-based approach is taken [55] events are classified asNC-like if the event contains no reconstructed track or ifthe track extends no more than six planes past the end ofthe shower The resulting distribution of NC interactions inthe near detector is shown in Figure 8 The NC identificationefficiency is 89 with 61 purity This selection will identify97 of ]
119890CC interactions as NC events therefore an analysis
of NC interactions in the FD must account for the ]119890
appearance caused by a nonzero 12057913
34 Selection of Atmospheric Neutrinos Atmospheric neu-trino interactions are selected out of any activity seen in
the FD outside of the 10 120583s periods when the NuMI beamis active [44] The oscillation signal is contained in the ]
120583
CC interactions and as with the beam-induced interactionsthese are identified by the presence of a muon track The FDbegan taking data with atmospheric neutrinos in July 2003two years before the NuMI beam began running
The FD has a single-hit timing resolution of 25 ns Thistiming information is used to determine the direction inwhich the detector activity is traveling Any downwardstraveling activity is required to begin well inside the detec-tor to eliminate cosmic muons entering from above Allupwards or horizontally traveling activity is almost certainto be neutrino-induced since no other particle can survivethrough the many kilometres of rock All activity with azenith angle of cos 120579
119911lt 014 is defined as horizontal or down-
going this corresponds to an overburden of at least 14 kmwater equivalent
From this sample of neutrino-induced activity all eventswith a track crossing at least eight planes are designatedtrack-like all events with only shower-like activity crossing atleast four planes are designated shower-like These track-likeand shower-like samples are used in the neutrino oscillationmeasurementsThe track-like sample contains the oscillationsignal of ]
120583disappearance The shower-like sample contains
mainly NC interactions and ]119890and ]
119890CC interactions it
shows little oscillation signal but is very important for settingthe normalization of the atmospheric neutrino flux
4 Muon Neutrino andAntineutrino Disappearance
The atmospheric oscillation parameters |Δ1198982| and sin2(2120579)aremeasured by observing and fitting the energy dependenceof ]120583and ]
120583disappearance To minimise the impact of
8 Advances in High Energy Physics
20
40
60
80
100
120
0 10 15 20 30 50
Even
tstimes10
4(G
eV)
MINOS near detector dataMCMC uncertaintyNC background
MINOS near detectorLow energy beam 120583-mode729 times 1020 POT
Reconstructed 120583 energy (GeV)5
Figure 9 The energy spectrum of ]120583CC interactions observed in
the ND compared to the simulation
systematic uncertainties the energy spectra of the ]120583and
]120583CC interactions observed in the ND (shown in Figure 9
for the neutrino-dominated beam) are used to predict thespectrum at the FD in the absence of oscillation [23 56]The neutrino energy spectra at the ND and FD are notidentical the ND subtends a relatively large angle to thebeam so for each pion or kaon a range of decay anglescan produce a neutrino that passes through the detectorcorresponding to a range of neutrino energies However theFD is effectively a point when viewed from the neutrinoproduction location so a single decay angle for each hadrontherefore a single neutrino energy contributes to the fluxTo take this difference into account the hadron-decay kine-matics are encoded into a beam transfer matrix that convertsthe observed ND flux into a predicted FD flux Once theND data has been used in this way the most importantsystematic uncertainties are those that can affect the twodetectors differently primarily reconstruction efficienciesand miscalibrations of the neutrino energy measurementin the detectors [57] These uncertainties are included inthe fit that extracts the oscillation parameters [58] Theuncertainty on the reconstruction efficiency is modeled as a16 uncertainty on the relative rate of events between theND and FD The uncertainty on the measurement of muonenergy has two components that are fully correlated betweenthe detectors a 2 uncertainty on energies measured fromrange and a 3 uncertainty on energies measured fromthe curvature in the magnetic field The uncertainty in thehadronic energy measurements also has two componentsAn uncertainty arising from shower modeling uncertaintiesand calibration is fully correlated between the detectorsand is parameterized as (66 + 35119890119864shw14GeV) The secondcomponent is uncorrelated between the detectors and is 19
in theND and 11 in the FD this is dominated by calibrationuncertainties
The top row of Figure 10 shows the predicted spectra of]120583and ]120583CC interactions from the neutrino-dominated and
antineutrino-enhanced beams at the FD along with the dataIn the neutrino-dominated beam an additional sample isused consisting of neutrinos interacting outside the fiducialvolume of the detector and in the rock surrounding thedetector [59 60] This nonfiducial sample consists mainlyof high energy neutrinos and has significantly lower res-olution as not all the energy is contained in the detectorhowever it does contain some oscillation information Intotal 8100 reconstructed neutrino events are used in theanalysis without oscillations 9471 would be expected Inall samples a clear energy-dependent deficit of ]
120583and
]120583interactions is observed The ratio of the data to the
expectation for the ]120583interactions in the neutrino-dominated
beam is shown in Figure 11This ratio shows the ldquodip and riserdquoenergy dependence of the deficit which is characteristic ofoscillation and described by (1)
The bottom row of Figure 10 shows the spectra of atmo-spheric ]
120583and ]120583CC interactions as a function of 119871119864 where
119871 is the distance traveled by the neutrino and 119864 is its energyThe atmospheric neutrino events are divided into ]
120583and ]120583
interactions according to the direction of curvature of themuon and separated into samples depending on whether ornot the interaction vertex is contained in the detector
All the observed ]120583and ]120583CC interactions are fit accord-
ing to the two-flavour model of (1) under the assumptionthat neutrinos and antineutrinos have the same oscillationparametersThe resultingmeasurement of |Δ1198982| and sin2(2120579)is shown in Figure 12 The fit yields |Δ1198982| = (241
+009
minus010) times
10minus3 eV2 and sin2(2120579) = 0950
+0035
minus0036 disfavouring maximal
mixing at the 86 confidence level Figure 12 compares thismeasurement to those from Super-Kamiokande [61] andT2K [62] The MINOS measurement is the most precisedetermination of |Δ1198982| and all measurements of sin2(2120579) areconsistent
41 Muon Antineutrino Disappearance In the standardmodel of neutrino oscillation neutrinos and antineutrinosobey the same parameters with CPT symmetry requiringthat the masses of particles and antiparticles are identicalThe most sensitive test of this symmetry in other sectors isfrom the kaon system [63] The data from the antineutrino-enhanced beam and the interaction of atmospheric antineu-trinos enables the first direct comparison of the neutrinoand antineutrino oscillation parameters in the atmosphericregion This comparison provides a limit on nonstandardinteractions with the matter being passed through by theneutrino beam [64ndash70]
Figure 10 showed the energy spectra of ]120583interactions
observed in the FD These spectra can be fit in the two-flavour model of (1) allowing the antineutrino oscillationparameters to differ from those for neutrinos This fit yieldsthe antineutrino parametermeasurement shown in Figure 13|Δ1198982| = (250
+023
minus025) times 10
minus3 eV2 and sin2(2120579) = 097+003
minus008
This is in excellent agreement with the parameters measured
Advances in High Energy Physics 9
Neutrino energy (GeV) Neutrino energy (GeV) Neutrino energy (GeV)
0
20
40
60
80
0
5
10
10
15
1515
20
20
25
25
30
Muon energy (GeV)
0
200
400
600
800
0
100
200
300
400
500
6001071 times 1020 POT
Even
ts (G
eV)
Even
ts (G
eV)
Even
ts (G
eV)
Even
ts (G
eV)
120583 120583
120583120583
0 02 4 56 0 2 4 68 910 12 14 0 2 4 6 8 10 12 14
Neutrino beam Neutrino beam Neutrino beam Antineutrino beam
contained-vertex 120583
nonfiducial 120583contained-vertex 120583
contained-vertex 120583 336 times 1020 POT
(a)
0
20
40
60
0
10
20
30
0
10
20
30
0
5
10
15
20
25
MINOS dataBest fit oscillationsNo oscillations
NC backgroundCosmic-ray muons
120583 120583 120583 120583
0 1 2 3 4 0 1 2 3 4 0 1 2 3 4 0 1 2 3 4
Even
ts
Even
ts
Even
ts
Even
ts
Atmos contained-vertex 120583 Atmos nonfiducial 120583minus Atmos nonfiducial 120583+3788kton-years
Atmos contained-vertex 120583
log10( (km)E (GeV)) log10( (km)E120583 (GeV))L L log10( (km)E (GeV))L log10( (km)E120583 (GeV))L
(b)
Figure 10 The energy spectra of ]120583and ]
120583CC interactions observed at the FD compared to the expectation with and without oscillation
(a) shows beam-induced neutrinos (b) shows atmospheric neutrinos
with neutrinos alone (the red line in Figure 13) It should benoted that the first MINOS measurement of the antineutrinooscillation parameters released in 2010 [17] yielded a notabletension between the ] and ] oscillation parameters whichwere in agreement only at the 20 confidence levelThis ten-sion was shown to be a statistical fluctuation as the additionof further data brought the ] and ] parameters measurementsinto good agreement [19 20]
5 Electron Neutrino andAntineutrino Appearance
A search for ]119890and ]
119890appearance in the ]
120583and ]
120583beams
enables a measurement of the mixing angle 12057913 It is critical
to know the level of background to the ]119890sample in the
FD The energy spectrum of background events measured inthe ND is used to predict the spectrum expected in the FDHowever the background consists of three components NCinteractions CC ]
120583and ]
120583interactions and the intrinsic ]
119890
component in the beam The relative contribution betweenthe ND and FD is different for all of these components sincethey are affected differently by oscillation and the kinematicsof the production in the beam are different Therefore each
backgroundmust be individually measuredTheNuMI beamcan be configured to produce neutrino beams of varyingenergy by altering the current passing through the magnetichorns and changing the relative positions of the target andhorns Between these different beam configurations therelative contributions of the three background componentschange in a well-understood way as shown in Figure 15By comparing the ND data to the simulation in the threedifferent beam configurations shown in the figure the contri-butions of the three background components can be extracted[71]
Using the data-driven background extraction procedurea total of 1277 background events are expected at the FDin the neutrino-dominated beam and 175 events in theantineutrino-enhanced beam In the data 152 and 20 eventsare observed respectively Figure 16 shows the energy spectraof these events divided into bins of the library eventmatchingdiscriminant variable Although CC ]
119890and ]119890events cannot
be separated on an event-by-event basis the change inthe relative numbers of neutrino and antineutrino inter-actions between the neutrino-dominated and antineutrino-enhanced beams is well knownThis allows separate limits tobe placed on the rates of ]
120583rarr ]119890and ]120583rarr ]119890transitions
on a statistical basis
10 Advances in High Energy PhysicsRa
tio to
no
osci
llatio
ns
05
1
15
2
25
0 10 15 20 30 50
MINOS far detector data
5Reconstructed 120583 energy (GeV)
1071 times 1020 POT
Prediction Δm2 = 241 times 10minus3eV2
Low energy beam 120583-mode
Figure 11 The ratio of the observed ]120583energy spectrum to the
expectation in the case of no oscillation in the neutrino-dominatedbeam The black points show the data the blue line shows the bestfit to the data
075 080 085 090 095 10015
20
25
30
35
40
90 CL68 CL
90 CL
sin2(2120579)
|Δm
2|(10minus3eV
2)
MINOS 3788 kt-yr atmospheric
336 times 1020 POT 120583 modeSuper-K zenith anglelowast
Super-K LElowast
T2Klowastlowast
lowastNeutrino 2012lowastlowastPRD 85 031103(R) (2012)
1071 times 1020 POT 120583 mode
Figure 12 The allowed regions for the atmospheric oscillationparameters |Δ1198982| and sin2(2120579) assuming identical neutrino andantineutrino oscillation parametersTheMINOS result is comparedto measurements from Super-Kamiokande [61] and T2K [62]
The data are fit to extract a measurement of 12057913 The
resulting measurement is shown in Figure 17 The measuredvalue of 120579
13depends on the CP violating phase 120575 which
directly affects the ]119890and ]
119890appearance probabilities and
themass hierarchy which affects the appearance probabilitiesthrough the interactions of the neutrinos with the matter in
MINOS 120583 disappearance1071 times 1020 POT 120583 mode336 times 1020 POT mode3788kt-yr atmospheric
90 CL120583120583120583 + 120583
120583120583120583 + 120583
Best fit
sin2(2120579) or sin2(2120579)
(|Δm
2|
or Δ
m2|)
(10minus3eV
2)
075 080 085 090 095 100
20
25
30
35
120583
|Figure 13 The allowed region for antineutrino oscillation param-eters (blue line) compared to the region measured with neutrinosalone (red line) and the region measured using both neutrinos andantineutrinos under the assumption they have the same parameters(black line)
20
25
30
20 25 30
|Δm
2| (10
minus3eV
2)
|Δm2| (10minus3eV2)
68 CL|Δm2| = |Δm2|
MINOS 120583 disappearance1071 times 1020 POT 120583 mode336 times 1020 POT mode3788kt-yr atmospheric
90 CLBest fit
120583
Figure 14 A comparison of the measured limits on the masssplittings of neutrinos and antineutrinos
the Earthrsquos crust Assuming a normal mass hierarchy 120575 = 0and 120579
23lt 1205874 MINOS measures 2sin2(2120579
13)sin2(120579
23) =
0051+0038
minus0030 Assuming an inverted mass hierarchy 120575 = 0
and 12057923
lt 1205874 MINOS measures 2sin2(212057913)sin2(120579
23) =
0093+0054
minus0049 This measurement is consistent with the results
from reactor neutrino searches [72ndash74] and the T2K experi-ment [75]
This MINOS measurement is the first ever search for ]119890
appearance in a long-baseline ]120583beam and the first search
Advances in High Energy Physics 11
Reconstructed energy (GeV)0 6 8
Frac
tion
of ev
ents
0
01
02
03
04
Standard MC
MINOS
2 4
Near detector 2011
NC120583-CCe-CC
(a)
Horn-off MC
Reconstructed energy (GeV)0 6 8
Frac
tion
of ev
ents
0
01
02
03
04 MINOS
2 4
Near detector 2011
NC120583-CCe-CC
(b)
High energy MC
Reconstructed energy (GeV)0 6 8
Frac
tion
of ev
ents
0
01
02
03
04 MINOS
2 4
Near detector 2011
NC120583-CCe-CC
(c)
Figure 15 The contribution of the three components to the background in the ]119890appearance search as simulated in the ND (a) the regular
(low energy) beam data (b) with no current in the NuMI focusing horns (c) a high energy beam configuration
for ]119890and ]119890appearance with significant matter effects Both
of these effects provide some sensitivity to the neutrinomass hierarchy and CP violation when the MINOS data iscompared to the measurements made by reactor neutrinosearches [72ndash74] (we have calculated a limit of sin2(2120579
13) =
0098 plusmn 0013 from the reactor data at the time of analysis)The sensitivity of MINOS to the mass hierarchy and CPviolation is modest but this contributes to the first analysisof the type that will be used by all future long-baselineexperiments The resulting values of the likelihood by whichMINOS disfavours various values of these parameters areshown in Figure 18 [76]
6 Search for Sterile Neutrino Mixing UsingNeutral-Current Interactions
The energy spectrum of NC interactions in the FD should beunchanged by standard neutrino oscillationThe existence ofone or more sterile neutrino flavours ]
119904 could cause a deficit
in the observed NC interaction rate As with all the MINOSoscillation analyses the energy spectrum of NC interactionsobserved in the ND (which was shown in Figure 8) is usedto predict the spectrum expected at the FD [77] The FDexpectation is shown in Figure 19 with the dashed blue linetaking into account ]
119890appearance corresponding to 120579
13=
115∘ (at the limit set by CHOOZ [78] and a little above
the current accepted value [29 72ndash75] this analysis usesonly the first 707 times 10
20 protons on target of data andwas performed before the recent positive measurements ofa nonzero 120579
13) The data are also shown in the figure and
are in good agreement with the expectation confirming thestandard model of neutrino oscillation This agreement canbe quantified using a test statistic 119877
119877 =119873data minus 119861CC
119878NC (7)
where 119873data is the number of events observed 119861CC is thepredicted background of CC interactions and 119878NC is the
predicted number of NC interactions A value of 119877 = 101 plusmn
006(stat) plusmn 005(syst) is obtained (over the full energy range0ndash120GeV) which is in good agreement with the expectationof 119877 = 1 in the case of no mixing with sterile neutrinos
The data are analysed with a model that assumes a singlesterile neutrino flavour mixing through the addition of afourth neutrino mass state119898
4≫ 1198983 This introduces a mass
splitting Δ119898243
with magnitude O(1 eV2) such that no oscil-lation-induced change to the event rate is observed at theND and the oscillatory energy dependence of the induceddepletion at the FD is so rapid that an overall uniform deple-tion is observed once the energy resolution of the detectors isaccounted forThismodel introduces three additionalmixingangles 120579
14 12057924 and 120579
34 MINOS is insensitive to 120579
14but sets
limits of 12057924= (00
+5
minus00)∘ and 120579
34= (00
+25
minus00)∘ These limits are
evaluated assuming 12057913at the CHOOZ limit
The limit on the coupling of sterile to active neutrinos canbe quantified by defining 119891
119904 the fraction of disappearing ]
120583
which have oscillated into ]119904
119891119904=
119875]120583rarr ]119904
1 minus 119875]120583rarr ]120583
(8)
For the model used in which 1198984≫ 119898
3 119891119904is evaluated
at 14 GeV the energy of maximal ]120583disappearance To
determine the limit on 119891119904 a large number of test values
are chosen of the mixing angles 12057924 12057934 and 120579
23 from
Gaussian distributions according to the measured values and1120590 uncertainties given above (with 120579
23constrained from the
measurements with CC ]120583interactions) 119891
119904is calculated for
each case and the value of 119891119904that is larger than 90 of the
test cases represents the limit MINOS limits 119891119904lt 040 at the
90 confidence level
7 The Future MINOS+
The MINOS experiment has made some very importantcontributions to our understanding of neutrino oscillation
12 Advances in High Energy Physics
Reconstructed energy (GeV)
Reconstructed energy (GeV)
Even
ts
30
0
10
20
Even
ts
30
0
10
20
Even
ts
30
0
10
20
2 4 6 8
2 4 6 8
Reconstructed energy (GeV)2 4 6 8
06 lt 120572LEM lt 07
MINOS far detector data
07 lt 120572LEM lt 08
120572LEM gt 08
mode
mode
mode
e CC signal
e CC signalBackgroundData
(a)
Even
ts
Reconstructed energy (GeV)2 4 6 8
Reconstructed energy (GeV)2 4 6 8
Reconstructed energy (GeV)2 4 6 8
06 lt 120572LEM lt 07
MINOS far detector data
Merged for fit
07 lt 120572LEM lt 08
120572LEM gt 08
mode
mode
mode
8
6
4
2
0
Even
ts
8
6
4
2
0
Even
ts
8
6
4
2
0
e CC signal
e CC signalBackgroundData
5ndash8GeV bins
(b)
Figure 16 The CC ]119890(a) and ]
119890(b) candidate events selected in the FD compared to the expectation without any ]
119890appearance (red) and
with the best fit for 12057913(purple) The events are divided into bins of the library event matching discriminant variable
Advances in High Energy Physics 13
20
15
10
05
000 01 02 03 04
2sin2(212057913)sin212057923
Δm2 gt 0
sin
120575(120587)
(a)
20
15
10
05
000 01 02 03 04
2sin2(212057913)sin212057923
MINOS best fit 12057923 lt 1205874
MINOS best fit 12057923 gt 1205874
Δm2 lt 0
MINOS
106 times 1020 POT -mode33 times 1020 POT -mode
68 CL 12057923 lt 1205874
90 CL 12057923 lt 1205874
120575(120587)
(b)
Figure 17 The allowed regions for 2sin2(212057913)sin2(120579
23)
120575(120587)
Δm2 gt 0 12057923 gt 1205874
Δm2 gt 0 12057923 lt 1205874
Δm2 lt 0 12057923 gt 1205874Δm2 lt 0 12057923 lt 1205874
3
2
1
00 1 1505 2
MINOS
90 CL
68 CL
minus2Δ
(L)
ln
Figure 18 The values of likelihood 119871 by which various values oftheCP violating parameter 120575 the mass hierarchy and the octant of12057923are disfavouredThis analysis uses MINOS data and information
from reactor neutrino measurements of 12057913[72ndash74]
physics and has finished taking data with the low energybeam for which it was designed However the experimentwill continue taking data and producing new results for thenext few years as MINOS+ [79] The NuMI beam is being
20
2018161410 12
Far detector data
Even
ts (G
eV)
00 2 4 6 8
40
60
80
100
120
140
12057913 = 0∘
12057913 = 115∘ 120575 = 120587 Δm232 gt 0
120583 CC background|Δm2
32| = 232 times 10minus3eV2
Ereco (GeV)
sin2212057923 = 1
Figure 19 The black dots show the energy spectrum of NCinteractions observed in the far detector The red lines show theexpectation in the case of no sterile neutrinos and 120579
13= 0 the blue
dashed line shows the same expectation with 12057913= 115
∘
upgraded to a higher energy and intensity for the NO]Aexperiment the far detector of which will sit 14 mrad offaxisNO]A will receive a narrow-band beam peaking at around2GeV which is ideal for searching for ]
119890appearance since
the background seen in MINOS from NC interactions ofhigh energy neutrinos will be heavily reduced Figure 20shows that the MINOS FD will see an intense ]
120583beam
14 Advances in High Energy Physics
1000
500
00 5 10 15 20
E (GeV)
MINOS+NOAMINOS
Preliminary
Simulated beam54 kton 6 times 1020 POT
120583CC
even
ts (G
eV)
Figure 20 The ]120583energy spectrum that will be observed by the
MINOS+ FD compared to the spectra observed by MINOS andNO]A
peaking at around 7GeV In this configuration MINOS+ willobserve around 4000 CC ]
120583interactions in the FD each
year unprecedented statistics for a long-baseline oscillationexperimentThis will offer a unique high precision test of thethree-flavour oscillation paradigm
MINOS+ will be able to make a very sensitive searchfor the sterile neutrinos suggested by the LSND [80] andMiniBooNE [81 82] data and by some interpretations ofreactor neutrino data [83] This search will cover more thanthree orders of magnitude in the mass splitting between thesterile and active neutrinos The signal that MINOS+ willsearch for is illustrated in Figure 21 Figure 21(a) illustratesthe increase in statistical precision thatMINOS+will provideon the ratio of the observed CC ]
120583interaction rate to
that expected without oscillations Figure 21(b) shows howthis ratio is modified if a sterile neutrino exists and mixeswith the active neutrinos an additional deficit of muonneutrino interactions occurs in the higher energy region ofthe spectrum In the model assumed here which introducesa single sterile neutrino state three new mixing angles areintroduced 120579
14 12057924 and 120579
34 An additional mass splitting
Δ1198982
43is also introduced The position in energy of the
additional deficit is governed by the value of the new masssplittingThemagnitude of the additional deficit in the CC ]
120583
interaction rate is governed primarily by the size of 12057924 this is
in comparison to short-baseline searches for ]119890disappearance
from reactors which are governed by 12057914and searches for ]
119890
appearance in ]120583beamswhich are governed by a combination
of 12057914
and 12057924 A detailed explanation of the global effort to
search for sterile neutrinos can be found in [84]The sensitivity of the MINOS+ experiment when com-
bined with the Bugey reactor neutrino data [85] is shown in
MINOS+ simulation
MINOS 1071 times 1021 POT06 times 1021 POT12 times 1021 POT18 times 1021 POT
120583su
rviv
al p
roba
bilit
y
Neutrino energy (GeV)0 5 10 15
15
1
05
0
(a)
P(
120583rarr
120583)
No sterile neutrinosΔm2
43 = 2 times 10minus2eV2 sin2(212057924) = 02
0 5 10 15 20
1
0
18
06
04
02
Neutrino energy (GeV)
(b)
Figure 21 (a) The black points show the ratio of the observed ]120583
energy spectrum to the expectation in the case of no oscillation inthe neutrino-dominated beam of MINOS The blue region showsthe statistical precision expected from MINOS+ (b) The black lineshows the muon neutrino survival probability in the case of nosterile neutrinos the red line shows how the probability would bemodified by the addition of mixing with a sterile neutrino
Figure 22 MINOS+ has the potential to rule out much of theLSND allowed region MINOS+ will begin taking data in thelate summer of 2013 and will continue taking data for at leasttwo years (Figure 22 assumes two years of data taking with aneutrino-dominated beam)
8 Conclusion
The MINOS experiment was conceived at a time when neu-trino oscillation had only recently been confirmed as thesolution to the problem of neutrino flavour change It has
Advances in High Energy Physics 15
Δm
2
10minus210minus2
10minus1
10minus1
10minus310minus4 1
1
10
102
LSND 90 CLLSND 99 CLKarmen2 90 CLBugey 90 CLlowast
MiniBooNE 90 CLMiniBooNE 99 CLMINOS+ and Bugeycombination 90 CL
sin22120579120583e
lowastGLoBES 2012 fit with new reactor fluxescourtesy of P Huber
Figure 22 The sensitivity of MINOS+ to the existence of sterileneutrinos when combined with data from the Bugey [85] reactorneutrino experiment Δ1198982 is the splitting between the three knownneutrino mass states and a new fourth state 120579
120583119890is the mixing angle
governing ]120583rarr ]119890transitions when a fourth sterile neutrino state
is introduced into the PMNSmixingmatrixThis figure assumes twoyears of MINOS+ running with a neutrino-dominated beam
played a hugely influential role in bringing neutrino oscilla-tion physics into an era of precision measurement MINOSrsquosmeasurement of the largest neutrino mass splitting is themost precise in the world MINOS has made the first directprecision measurement of the corresponding antineutrinoparameters a measurement that promises to remain theworldrsquos most precise for many years And MINOS has playeda role in the discovery of a nonzero value for 120579
13
Now that the value of 12057913is known the neutrino physics
community can move on to determine the neutrino masshierarchy and to search for CP violation in the neutrinosector MINOS has pioneered a number of techniques thatwill be used by future experiments The two-detector setupall important in reducing the impact of systematic uncer-tainties is the design of choice for any new experiment andMINOS has demonstrated methods of using a near detectorto determine the expectation at a far detector MINOS hasperformed the first search for ]
119890appearance in a ]
120583beam
and the first search for ]119890and ]119890appearance with significant
matter effects demonstrating the analysis techniques that willbe used to determine the mass hierarchy and CP violationparameter
In the second half of 2013 MINOS will begin taking dataas the MINOS+ experiment which will make ever more pre-cise tests of the three-flavour neutrino oscillation paradigmand set world-leading limits on the existence of sterileneutrinos This is an exciting future for an experiment thatwith a decade of data taking so far has already created alasting legacy for itself in our understanding of the neutrino
A comparison of themeasured neutrino and antineutrinomass splittings is shown in Figure 14 the difference betweenthe two is constrained to |Δ119898
2| minus |Δ119898
2| = (012
+024
minus026) times
10minus3 eV2
Acknowledgment
The work of the MINOS and MINOS+ collaborations issupported by the US DoE the UK STFC the US NSF theState and University of Minnesota the University of Athensin Greece and Brazilrsquos FAPESP and CNPq The authors aregrateful to the Minnesota Department of Natural Resourcesthe crew of the Soudan Underground Laboratory and thepersonnel of Fermilab for their vital contributions
References
[1] S Wojcicki ldquoLong baseline neutrino oscillation programe inthe United Statesrdquo Nuclear Physics B vol 77 no 1ndash3 pp 182ndash186 1999 Proceedings of the 18th International Conference onNeutrino Physics and Astrophysics (Neutrino rsquo98) TakayamaJapan June 1998
[2] R Davis Jr D S Harmer and K C Hoffman ldquoSearch forneutrinos from the sunrdquo Physical Review Letters vol 20 no 21pp 1205ndash1209 1968
[3] A I Abazov O L Anosov E L Faizov et al ldquoSearch forneutrinos from sun using the reactionGa-71 (electron-neutrinoe-) Ge-71rdquo Physical Review Letters vol 67 pp 3332ndash3335 1991
[4] P Anselmann W Hampel G Heusser et al ldquoSolar neutrinosobserved by GALLEX at gran sassordquo Physics Letters B vol 285no 4 pp 376ndash389 1992
[5] M Aglietta G Battistoni E Bellotti et al ldquoExperimentalstudy of atmospheric neutrino flux in the NUSEX experimentrdquoEurophysics Letters vol 8 no 7 article 611 1989
[6] K S Hirata ldquoObservation of a small atmospheric V120583V119890ratio in
Kamiokanderdquo Physics Letters B vol 280 no 1-2 pp 146ndash1521992
[7] R Becker-Szendy C B Bratton D Casper et al ldquoElectron-and muon-neutrino content of the atmospheric fluxrdquo PhysicalReview D vol 46 pp 3720ndash3724 1992
[8] K Daum W Rhode P Bareyre et al ldquoDetermination ofthe atmospheric neutrino spectra with the frejus detectorrdquoZeitschrift fur Physik C vol 66 no 3 pp 417ndash428 1995
[9] S Ahlen M Ambrosio R Antolini and G Auriemma ldquoAtmo-spheric neutrino flux measurement using upgoing muonsrdquoPhysics Letters B vol 357 no 3 pp 481ndash486 1995
[10] WMAllison G J Alner D S Ayres et al ldquoMeasurement of theatmospheric neutrino flavour composition in Soudan 2rdquoPhysicsLetters B vol 391 no 3-4 pp 491ndash500 1997
16 Advances in High Energy Physics
[11] Y Fukuda T Hayakawa E Ichihara et al ldquoEvidence foroscillation of atmospheric neutrinosrdquo Physical Review Lettersvol 81 no 8 pp 1562ndash1567 1998
[12] Q R Ahmad R C Allen T C Andersen et al ldquoMeasurementof charged current interactions produced by solar neutrinos atthe sudbury neutrino observatoryrdquo Physical Review Letters vol87 Article ID 071301 2001
[13] Q R Ahmad R C Allen T C Andersen et al ldquoDirect evidencefor neutrino flavor transformation from neutral-current inter-actions in the sudbury neutrino observatoryrdquo Physical ReviewLetters vol 89 Article ID 011301 6 pages 2002
[14] B Pontecorvo ldquoInverse beta processes and nonconservation oflepton chargerdquo Journal of Experimental and Theoretical Physicsvol 34 pp 172ndash173 1958
[15] V N Gribov and B Pontecorvo ldquoNeutrino astronomy andlepton chargerdquo Physics Letters B vol 28 pp 493ndash496 1969
[16] Z Maki M Nakagawa and S Sakata ldquoRemarks on the unifiedmodel of elementary particlesrdquo Progress of Theoretical Physicsvol 28 no 5 pp 870ndash880 1962
[17] P Adamson C Andreopoulos D J Auty et al ldquoFirst directobservation of muon antineutrino disappearancerdquo PhysicalReview Letters vol 107 no 2 Article ID 021801 2011
[18] P Adamson D J Auty D S Ayres et al ldquoSearch for thedisappearance of muon antineutrinos in the NuMI neutrinobeamrdquo Physical Review D vol 84 no 7 Article ID 071103 6pages 2011
[19] P Adamson D S Ayres C Backhouse et al ldquoImprovedmeasurement of muon antineutrino disappearance inMINOSrdquoPhysical Review Letters vol 108 no 19 Article ID 191801 5pages 2012
[20] P Adamson I Anghel C Backhouse et al ldquoMeasurementof Neutrino and Antineutrino Oscillations Using Beam andAtmospheric Data in MINOSrdquo Physical Review Letters vol 110no 25 Article ID 251801 6 pages 2013
[21] K Anderson B Bernstein D Boehnlein et al ldquoThe NuMIFacility Technical Design Reportrdquo FERMILAB-DESIGN-1998-01 1998
[22] D G Michael P Adamson T Alexopoulos et al ldquoObservationof muon neutrino disappearance with the MINOS detectors inthe NuMI neutrino beamrdquo Physical Review Letters vol 97 no19 Article ID 191801 6 pages 2006
[23] P Adamson C Andreopoulos K E Arms et al ldquoStudy ofmuon neutrino disappearance using the fermilab main injectorneutrino beamrdquo Physical Review D vol 77 no 7 Article ID072002 34 pages 2008
[24] P Adamson C Andreopoulos K E Arms et al ldquoMeasurementof neutrino oscillations with theMINOS detectors in the NuMIbeamrdquo Physical Review Letters vol 101 no 13 Article ID 1318025 pages 2008
[25] P Adamson C Andreopoulos R Armstrong et al ldquoMea-surement of the neutrino mass splitting and flavor mixing byMINOSrdquo Physical Review Letters vol 106 no 18 Article ID181801 6 pages 2011
[26] P Adamson C Andreopoulos K E Arms et al ldquoSearch formuon-neutrino to electron-neutrino transitions in MINOSrdquoPhysical Review Letters vol 103 no 26 Article ID 261802 5pages 2009
[27] PAdamsonCAndreopoulosD J Auty et al ldquoNew constraintsonmuon-neutrino to electron-neutrino transitions inMINOSrdquoPhysical ReviewD vol 82 no 5 Article ID 051102 6 pages 2010
[28] P Adamson D J Auty D S Ayres et al ldquoImproved search formuon-neutrino to electron-neutrino oscillations in MINOSrdquoPhysical Review Letters vol 107 no 18 Article ID 181802 6pages 2011
[29] P Adamson I Anghel C Backhouse et al ldquoElectron neutrinoand antineutrino appearance in the full MINOS data samplerdquoPhysical Review Letters vol 110 no 17 Article ID 171801 6 pages2013
[30] P Adamson C Andreopoulos K E Arms et al ldquoSearch foractive neutrino disappearance using neutral-current interac-tions in theMINOS long-baseline experimentrdquo Physical ReviewLetters vol 101 no 22 Article ID 221804 5 pages 2008
[31] P Adamson C Andreopoulos D J Auty et al ldquoSearch for ster-ile neutrino mixing in the MINOS long-baseline experimentrdquoPhysical Review D vol 81 no 5 Article ID 052004 18 pages2010
[32] P Adamson D J Auty D S Ayres et al ldquoActive to sterileneutrino mixing limits from neutral-current interactions inMINOSrdquo Physical Review Letters vol 107 no 1 Article ID011802 5 pages 2011
[33] Z Pavlovic Observation of disappearance of muon neutrinos inthe NuMI beam [PhD thesis] University of Texas at AustinAustin Tex USA 2008
[34] F Ballarini G Battistoni M Campanella et al ldquoThe FLUKAcode an overviewrdquo Journal of Physics vol 41 article 151 2006
[35] S Agostinelli J Allison K Amako et al ldquoGEANT4mdasha sim-ulation toolkitrdquo Nuclear Instruments and Methods in PhysicsResearch A vol 506 no 3 pp 250ndash303 2003
[36] G Battistoni F Cerutti A Fasso et al ldquoThe FLUKA codedescription and benchmarkingrdquo in Proceedings of the HadronicShower Simulation Workshop vol 896 of AIP Conference Pro-ceedings pp 31ndash49 Batavia Ill USA September 2006
[37] D G Michaele P Adamson T Alexopoulos et al ldquoThe mag-netized steel and scintillator calorimeters of the MINOS exper-imentrdquoNuclear Instruments and Methods in Physics Research Avol 596 no 2 pp 190ndash228 2008
[38] I E Stockdale A Bodek F Borcherding N Giokaris et alldquoLimits on muon-neutrino oscillations in the mass range 30 lt9987791198982lt 1000 eV2c4 rdquo Physical Review Letters vol 52 no 16 pp
1384ndash1388 1984[39] F Dydak G J Feldman C Guyot et al ldquoA search for V
120583
oscillations in the9987791198982 range 03ndash90 eV2 rdquo Physics Letters B vol134 no 3-4 pp 281ndash286 1984
[40] F Bergsma J Dorenbosch M Jonker et al ldquoA searchfor oscillations of muon neutrinos in an experiment withLEcong07 kmGeVrdquo Physics Letters B vol 142 no 1-2 pp 103ndash1101984
[41] M H Ahn E Aliu S Andringa et al ldquoMeasurement ofneutrino oscillation by the K2K experimentrdquo Physical ReviewD vol 74 no 7 Article ID 072003 39 pages 2006
[42] P Adamson T Alexopoulos W W M Allison et al ldquoFirstobservations of separated atmospheric V
120583and ]
120583events in the
MINOS detectorrdquo Physical Review D vol 73 no 7 Article ID072002 2006
[43] P Adamson C Andreopoulos K E Arms et al ldquoCharge-separated atmospheric neutrino-inducedmuons in theMINOSfar detectorrdquo Physical ReviewD vol 75 no 9 Article ID 09200314 pages 2007
[44] P Adamson C Backhouse G Barr et al ldquoMeasurements ofatmospheric neutrinos and antineutrinos in the MINOS fardetectorrdquo Physical Review D vol 86 no 5 Article ID 05200720 pages 2012
Advances in High Energy Physics 17
[45] M A Kordosky Hadronic interactions in the MINOS detectors[PhD thesis] University of Texas at Austin Austin Tex USA2004
[46] P L Vahle Electromagnetic interactions in the MINOS detectors[PhD thesis] University of Texas at Austin Austin Tex USA2004
[47] C Backhouse Measuring neutrino oscillation parameters using]120583disappearance inMINOS [PhD thesis] University of Oxford
Oxford UK 2011[48] T M Cover and P E Hart ldquoNearest neighbor pattern classifi-
cationrdquo IEEE Transactions on Information Theory vol 13 no 1pp 21ndash27 1967
[49] R Ospanov A measurement of muon neutrino disappearancewith the MINOS detectors and NuMI beam [PhD thesis]University of Texas at Austin Austin Tex USA 2008
[50] J S Marshall A study of muon neutrino disappearance with theMINOS detectors and the NuMI neutrino beam [PhD thesis]University of Cambridge Cambridge UK 2008
[51] J P OchoaA search formuon neutrino to electron neutrino oscil-lations in the MINOS Experiment [PhD thesis] The CaliforniaInstitute of Technology Pasadena Calif USA 2009
[52] R TonerMeasuring 12057913via muon neutrino to electron neutrino
oscillations in the MINOS experiment [PhD thesis] Universityof Cambridge Cambridge UK 2011
[53] A Holin Electron neutrino appearance in the MINOS experi-ment [PhD thesis] University College London London UK2010
[54] J Boehm Measurement of electron neutrino appearance withthe MINOS experiment [PhD thesis] Harvard UniversityCambridge Mass USA 2009
[55] G Tinti Sterile neutrino oscillations in MINOS and hadronproduction in pC collisions [PhD thesis] University of OxfordOxford UK 2010
[56] J J EvansMeasuring antineutrino oscillations with the MINOSexperiment [PhD thesis] University of Oxford Oxford UK2008
[57] S J ColemanAmeasurement of neutrino oscillations withmuonneutrinos in the MINOS experiment [PhD thesis] College ofWilliam ampMary Williamsburg Va USA 2011
[58] J S Mitchell Measuring ]120583disappearance with the MINOS
experiment [PhD thesis] University of Cambridge CambridgeUK 2011
[59] A McGowan Observation of deficit in NuMI neutrino-inducedrock and non-fiducial muons in MINOS far detector andmeasurement of neutrino oscillation parameters [PhD thesis]University of Minnesota Minneapolis Minn USA 2007
[60] M StraitMeasurement of neutrino oscillation parameters usinganti-fiducial charged current events in MINOS [PhD thesis]University of Minnesota Minneapolis Minn USA 2010
[61] Y Itow ldquoAtmospheric neutrinosmdashresults from running exper-imentsrdquo in Proceedings of the 25th International Conference onNeutrino Physics and Astrophysics (Neutrino rsquo12) Kyoto JapanJune 2012
[62] K Abe N Abgrall Y Ajima et al ldquoFirst muon-neutrinodisappearance study with an off-axis beamrdquo Physical Review Dvol 85 no 3 Article ID 031103 8 pages 2012
[63] K Nakamura ldquoReview of particle physicsrdquo Journal of Physics Gvol 37 Article ID 075021 2010
[64] L Wolfenstein ldquoNeutrino oscillations in matterrdquo PhysicalReview D vol 17 no 9 pp 2369ndash2374 1978
[65] J W F Valle ldquoResonant oscillations of massless neutrinos inmatterrdquo Physics Letters B vol 199 no 3 pp 432ndash436 1987
[66] M C Gonzalez-Garcia M M Guzzo P I Krastev et alldquoAtmospheric neutrino observations and flavor changing inter-actionsrdquo Physical Review Letters vol 82 no 16 pp 3202ndash32051999
[67] A Friedland C Lunardini and M Maltoni ldquoAtmosphericneutrinos as probes of neutrino-matter interactionsrdquo PhysicalReview D vol 70 no 11 Article ID 111301 2004
[68] Z IsvanAntineutrino oscillations and a Search for non-standardInteractions with the MINOS [PhD thesis] University of Pitts-burgh Pittsburgh Pa USA 2012
[69] W A Mann D Cherdack W Musial and T Kafka ldquoApparentmultiple 998779119898
32
2 in ]120583and V
120583survival oscillations from nonstan-
dard interactionmatter effectrdquo Physical Review D vol 82 no 11Article ID 113010 8 pages 2010
[70] J Kopp P A N Machado and S J Parke ldquoInterpretation ofMINOS data in terms of nonstandard neutrino interactionsrdquoPhysical Review D vol 82 no 11 Article ID 113002 12 pages2010
[71] J A B Coelho Investigacao de mecanismos alternativos aoscilacao de neutrinos no experimentos MINOS [PhD thesis]Universidade Estadual de Campinas Sao Paulo Brazil 2012
[72] F P An Q An J Z Bai A B Balantekin et al ldquoImprovedmeasurement of electron antineutrino disappearance at DayaBayrdquo Chinese Physics C vol 37 Article ID 011001 21 pages 2013
[73] J K Ahn S Chebotaryov J H Choi et al ldquoObservationof reactor electron antineutrinos disappearance in the RENOexperimentrdquo Physical Review Letters vol 108 Article ID 1918026 pages 2012
[74] Y Abe C Aberle J C dos Anjos et al ldquoReactor electronantineutrino disappearance in the Double Chooz experimentrdquoPhysical Review D vol 86 Article ID 052008 2012
[75] K Abe N Abgrall H Aihara et al ldquoEvidence of electronneutrino appearance in a muon neutrino beamrdquo PhysicalReview D vol 88 no 3 Article ID 032002 41 pages 2013
[76] A Schreckenberger Electron neutrino and antineutrino appear-ance in the MINOS detector [PhD thesis] University of Min-nesota Minneapolis Minn USA 2013
[77] D J Koskinen MINOS sterile neutrino search [PhD thesis]University College London London UK 2009
[78] M Apollonio A Baldini C Bemporad et al ldquoSearch forneutrino oscillations on a long base-line at the CHOOZ nuclearpower stationrdquoTheEuropean Physical Journal C vol 27 pp 331ndash374 2003
[79] G Tzanankos M Bishai M Diwan et alMINOS+ a proposalto FNAL to run MINOS with the medium energy NuMI beam[PhD thesis] University of Athens Athens Greece 2011
[80] A Aguilar L B Auerbach R L Burman et al ldquoEvidence forneutrino oscillations from the observation of ]
119890e appearance
in a ]120583beamrdquo Physical Review D vol 64 Article ID 112007 22
pages 2001[81] A A Aguilar-Arevalo C E Anderson S J Brice et al ldquoSearch
for electron antineutrino appearance at the Δ119898 sim 1 eV2 ScalerdquoPhysical Review Letters vol 103 no 11 Article ID 111801 2009
[82] A A Aguilar-Arevalo C E Anderson A O Bazarko et alldquoImproved search for V
120583rarr V119890oscillations in the MiniBooNE
experimentrdquo Physical Review Letter vol 110 no 10 Article ID161801 2013
[83] GMentionM Fechner T Lasserre et al ldquoReactor antineutrinoanomalyrdquo Physical Review D vol 83 Article ID 073006 20pages 2011
18 Advances in High Energy Physics
[84] KNAbazajianMAAcero S KAgarwalla et al ldquoLight sterileneutrinos a white paperrdquo httparxivorgabs12045379
[85] B Achkar R Aleksan M Avenier et al ldquoSearch for neutrinooscillations at 15 40 and 95meters from a nuclear power reactorat Bugeyrdquo Nuclear Physics B vol 434 no 3 pp 503ndash532 1995
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
High Energy PhysicsAdvances in
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
FluidsJournal of
Atomic and Molecular Physics
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in Condensed Matter Physics
OpticsInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
AstronomyAdvances in
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Superconductivity
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Statistical MechanicsInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
GravityJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
AstrophysicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Physics Research International
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Solid State PhysicsJournal of
Computational Methods in Physics
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Soft MatterJournal of
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AerodynamicsJournal of
Volume 2014
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PhotonicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Biophysics
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
ThermodynamicsJournal of
Advances in High Energy Physics 5
CC 120583 event
120583minus
15
1
05
0
0
05 1 15 2 25 3 35 4
Longitudinal position (m)
Tran
sver
se p
ositi
on (m
)
minus05
(a)
V
06
04
02
0
minus02
minus02
minus04
minus04
minus06
0 02 04 06 08 1
NC event
Longitudinal position (m)
Tran
sver
se p
ositi
on (m
)
(b)
e
02
0
02
0 05 1
CC e event
Longitudinal position (m)
Tran
sver
se p
ositi
on (m
)
lowast
(c)
Figure 5 Neutrino interaction topologies observed in the MINOS detectors (a) A CC ]120583interaction (b) A NC interaction (c) A CC ]
119890
interaction Each coloured rectangle represents an excited scintillator strip the colour indicating the amount of light purple and blue are lowlight levels through to orange and red for the highest light levels
The main background occurs at low energies and consists ofsmall cascades from NC interactions in which a low energyhadron such as a proton or a charged pion exhibits a track-like topology that mimics a low energy muon Four variablesare constructed that discriminate between muons trackswhich are typically long and show a constant energy deposi-tion along the length and spurious hadronic tracks which aretypically shorter and show greater fluctuations in the energydeposition These variables are the event length the averageenergy deposited per scintillator plane along the track thetransverse energy deposition profile and the fluctuation of
the energy deposition along the track These variables areinput into a 119896-nearest-neighbour algorithm which calculatesa single discrimination variable shown in Figure 6 [49]Events for which this variable is greater than 03 are selectedas CC ]
120583interactions yielding a sample with a total efficiency
of 90 below 2GeV the NC contamination is 65 Theefficiency and contamination are energy dependent this fullenergy dependence is shown in Figure 6
The CC interactions of ]120583and ]
120583result in very similar
topologies the 119896-nearest-neighbour discriminant is thereforeused in the same way in both the neutrino-dominated and
6 Advances in High Energy Physics
CCNC separation parameter
Low energy beamDataMC expectation
NC background
Even
ts10
16PO
T
10
1
10minus1
10minus2
0 02 04 06 08 1
(a)
Reconstructed neutrino energy (GeV)
0
02
04
06
08
1
NC contamination
Far detector fiducial onlyCC selection efficiency
0 2 4 6 8 10
Effici
ency
con
tam
inat
ion
(b)
Figure 6 (a) The discrimination variable used to separate ]120583CC interactions from hadronic backgrounds Events with a parameter value
greater than 03 are selected as ]120583CC interactions (b) The efficiency and background contamination of the selected ]
120583CC sample in the far
detector
antineutrino-enhanced beams When performing a directmeasurement of the antineutrino oscillation parameters anadditional selection cut is made requiring the charge of themuon track to be positiveThis uses the direction of curvatureof themuon asmeasured by aKalman Filter algorithm [50] Afurther sample of ]
120583CC interactions is obtained from the 7
]120583component in the neutrino-dominated beamThis sample
contains a significant background of ]120583events in which a 120583minus
has been identified with the incorrect charge often at lowenergies where the muon undergoes significant scatteringTherefore a much stricter set of selection criteria are appliedto purify this ]
120583sample [18]
32 Selection of Charged-Current ]119890Interactions The selec-
tion of ]119890CC interactions focuses on identifying the dense
showers from the electromagnetic interaction of the electronrather than the much more diffuse hadronic showers Theprimary background comes from purely hadronic showerswhich can have a denser than average energy depositparticularly in the presence of a neutral pion decaying tophotons Once a set of shower-like events in the signalregion of 1ndash8GeV has been obtained a pattern matchingapproach called library event matching is used to identifythe interactions most likely to be ]
119890CC [51 52] Each event
in the data is compared to a library of 5 times 107 simulated
signal and background events its similarity to the libraryevents is quantified by comparing the pattern of energydeposits in each scintillator strip excited by the shower wherethe energy deposit is quantified by the charge recorded onthe photomultiplier tube For an arbitrary energy depositthe mean expected charge on a photomultiplier tube willbe some value 120582 The probability of observing an amountof charge 119899 is then a Poisson distribution 119875(119899 | 120582) Thelikelihood L of a data event corresponding to the same
physical shower topology as a simulated library event cantherefore be calculated as
logL =
119873strips
sum
119894=1
log [intinfin
0
119875 (119899119894
data | 120582) 119875 (119899119894
lib | 120582) d120582] (6)
where 119894 represents the 119894th scintillator strip in the showerUsing this definition of the likelihood the 50 library eventsare identified that best match the data eventThree quantitiesare calculated from this set of 50 best-matching library eventsthe fraction of the events that are true ]
119890CC events the
average inelasticity of the true ]119890CC events and the average
fraction of charge that overlaps between the data event andeach ]
119890CC library event These three quantities are input to
a neural network which calculates a classification variableshown in Figure 7 Events with a classification variable valueabove 06 are selected for analysis this value was chosen tomaximise the sensitivity to ]
119890and ]119890appearance
The efficiency of the ]119890CC selection is estimated from
the data rather than relying totally on the simulation Toobtain a pure sample of true hadronic showers a sampleof well-identified ]
120583CC events is selected and the energy
depositions corresponding to the muon track are removed[53]The simulated energy depositions of an electron are theninserted [54] providing a realistic sample of ]
119890CC events
Using thismethod the ]119890CC identification efficiency is found
to be (574 plusmn 28) in the neutrino-dominated beam and(633 plusmn 31) in the antineutrino-enhanced beam
33 Selection of Neutral-Current Interactions The signal of anNC interaction is a diffuse hadronic shower ]
120583CC interac-
tions also produce hadronic showers and if the inelasticityis high the tell-tale muon track may not visibly extend pastthe shower To purify a sample of NC interactions a simple
Advances in High Energy Physics 7
sin2(212057913) = 01
Δm232 gt 0 120575cp = 0 12057923 =
120587
4
Background
MINOS far detector80
60
40
20
00 01 02 03 04 05 06 07 08 09 1
LEM discriminant
Signal times10
Even
ts8
2times10
20PO
T
(a)
LEM discriminant
Even
ts10
19PO
T
DataMonte Carlo
MINOS near detector8000
6000
4000
2000
00 01 02 03 04 05 06 07 08 09 1
(b)
Figure 7 (a) The library event matching discriminant showing the expected distribution for background and CC ]119890signal events in the far
detector in the neutrino-dominated beam Note that the signal simulated for sin2(212057913) = 01 120575 = 0 and a normal mass hierarchy has been
scaled up by a factor of ten for visibility (b)The same discriminant as observed in the near detector compared with the simulated expectation
Near detector dataMonte Carlo prediction
20
10
30
50
2018161410 120
0 2 4 6 8
40
60
120583 CC background
Ereco (GeV)
104
even
ts (G
eV)
Figure 8 The sample of events identified as NC interactions in thenear detector
cut-based approach is taken [55] events are classified asNC-like if the event contains no reconstructed track or ifthe track extends no more than six planes past the end ofthe shower The resulting distribution of NC interactions inthe near detector is shown in Figure 8 The NC identificationefficiency is 89 with 61 purity This selection will identify97 of ]
119890CC interactions as NC events therefore an analysis
of NC interactions in the FD must account for the ]119890
appearance caused by a nonzero 12057913
34 Selection of Atmospheric Neutrinos Atmospheric neu-trino interactions are selected out of any activity seen in
the FD outside of the 10 120583s periods when the NuMI beamis active [44] The oscillation signal is contained in the ]
120583
CC interactions and as with the beam-induced interactionsthese are identified by the presence of a muon track The FDbegan taking data with atmospheric neutrinos in July 2003two years before the NuMI beam began running
The FD has a single-hit timing resolution of 25 ns Thistiming information is used to determine the direction inwhich the detector activity is traveling Any downwardstraveling activity is required to begin well inside the detec-tor to eliminate cosmic muons entering from above Allupwards or horizontally traveling activity is almost certainto be neutrino-induced since no other particle can survivethrough the many kilometres of rock All activity with azenith angle of cos 120579
119911lt 014 is defined as horizontal or down-
going this corresponds to an overburden of at least 14 kmwater equivalent
From this sample of neutrino-induced activity all eventswith a track crossing at least eight planes are designatedtrack-like all events with only shower-like activity crossing atleast four planes are designated shower-like These track-likeand shower-like samples are used in the neutrino oscillationmeasurementsThe track-like sample contains the oscillationsignal of ]
120583disappearance The shower-like sample contains
mainly NC interactions and ]119890and ]
119890CC interactions it
shows little oscillation signal but is very important for settingthe normalization of the atmospheric neutrino flux
4 Muon Neutrino andAntineutrino Disappearance
The atmospheric oscillation parameters |Δ1198982| and sin2(2120579)aremeasured by observing and fitting the energy dependenceof ]120583and ]
120583disappearance To minimise the impact of
8 Advances in High Energy Physics
20
40
60
80
100
120
0 10 15 20 30 50
Even
tstimes10
4(G
eV)
MINOS near detector dataMCMC uncertaintyNC background
MINOS near detectorLow energy beam 120583-mode729 times 1020 POT
Reconstructed 120583 energy (GeV)5
Figure 9 The energy spectrum of ]120583CC interactions observed in
the ND compared to the simulation
systematic uncertainties the energy spectra of the ]120583and
]120583CC interactions observed in the ND (shown in Figure 9
for the neutrino-dominated beam) are used to predict thespectrum at the FD in the absence of oscillation [23 56]The neutrino energy spectra at the ND and FD are notidentical the ND subtends a relatively large angle to thebeam so for each pion or kaon a range of decay anglescan produce a neutrino that passes through the detectorcorresponding to a range of neutrino energies However theFD is effectively a point when viewed from the neutrinoproduction location so a single decay angle for each hadrontherefore a single neutrino energy contributes to the fluxTo take this difference into account the hadron-decay kine-matics are encoded into a beam transfer matrix that convertsthe observed ND flux into a predicted FD flux Once theND data has been used in this way the most importantsystematic uncertainties are those that can affect the twodetectors differently primarily reconstruction efficienciesand miscalibrations of the neutrino energy measurementin the detectors [57] These uncertainties are included inthe fit that extracts the oscillation parameters [58] Theuncertainty on the reconstruction efficiency is modeled as a16 uncertainty on the relative rate of events between theND and FD The uncertainty on the measurement of muonenergy has two components that are fully correlated betweenthe detectors a 2 uncertainty on energies measured fromrange and a 3 uncertainty on energies measured fromthe curvature in the magnetic field The uncertainty in thehadronic energy measurements also has two componentsAn uncertainty arising from shower modeling uncertaintiesand calibration is fully correlated between the detectorsand is parameterized as (66 + 35119890119864shw14GeV) The secondcomponent is uncorrelated between the detectors and is 19
in theND and 11 in the FD this is dominated by calibrationuncertainties
The top row of Figure 10 shows the predicted spectra of]120583and ]120583CC interactions from the neutrino-dominated and
antineutrino-enhanced beams at the FD along with the dataIn the neutrino-dominated beam an additional sample isused consisting of neutrinos interacting outside the fiducialvolume of the detector and in the rock surrounding thedetector [59 60] This nonfiducial sample consists mainlyof high energy neutrinos and has significantly lower res-olution as not all the energy is contained in the detectorhowever it does contain some oscillation information Intotal 8100 reconstructed neutrino events are used in theanalysis without oscillations 9471 would be expected Inall samples a clear energy-dependent deficit of ]
120583and
]120583interactions is observed The ratio of the data to the
expectation for the ]120583interactions in the neutrino-dominated
beam is shown in Figure 11This ratio shows the ldquodip and riserdquoenergy dependence of the deficit which is characteristic ofoscillation and described by (1)
The bottom row of Figure 10 shows the spectra of atmo-spheric ]
120583and ]120583CC interactions as a function of 119871119864 where
119871 is the distance traveled by the neutrino and 119864 is its energyThe atmospheric neutrino events are divided into ]
120583and ]120583
interactions according to the direction of curvature of themuon and separated into samples depending on whether ornot the interaction vertex is contained in the detector
All the observed ]120583and ]120583CC interactions are fit accord-
ing to the two-flavour model of (1) under the assumptionthat neutrinos and antineutrinos have the same oscillationparametersThe resultingmeasurement of |Δ1198982| and sin2(2120579)is shown in Figure 12 The fit yields |Δ1198982| = (241
+009
minus010) times
10minus3 eV2 and sin2(2120579) = 0950
+0035
minus0036 disfavouring maximal
mixing at the 86 confidence level Figure 12 compares thismeasurement to those from Super-Kamiokande [61] andT2K [62] The MINOS measurement is the most precisedetermination of |Δ1198982| and all measurements of sin2(2120579) areconsistent
41 Muon Antineutrino Disappearance In the standardmodel of neutrino oscillation neutrinos and antineutrinosobey the same parameters with CPT symmetry requiringthat the masses of particles and antiparticles are identicalThe most sensitive test of this symmetry in other sectors isfrom the kaon system [63] The data from the antineutrino-enhanced beam and the interaction of atmospheric antineu-trinos enables the first direct comparison of the neutrinoand antineutrino oscillation parameters in the atmosphericregion This comparison provides a limit on nonstandardinteractions with the matter being passed through by theneutrino beam [64ndash70]
Figure 10 showed the energy spectra of ]120583interactions
observed in the FD These spectra can be fit in the two-flavour model of (1) allowing the antineutrino oscillationparameters to differ from those for neutrinos This fit yieldsthe antineutrino parametermeasurement shown in Figure 13|Δ1198982| = (250
+023
minus025) times 10
minus3 eV2 and sin2(2120579) = 097+003
minus008
This is in excellent agreement with the parameters measured
Advances in High Energy Physics 9
Neutrino energy (GeV) Neutrino energy (GeV) Neutrino energy (GeV)
0
20
40
60
80
0
5
10
10
15
1515
20
20
25
25
30
Muon energy (GeV)
0
200
400
600
800
0
100
200
300
400
500
6001071 times 1020 POT
Even
ts (G
eV)
Even
ts (G
eV)
Even
ts (G
eV)
Even
ts (G
eV)
120583 120583
120583120583
0 02 4 56 0 2 4 68 910 12 14 0 2 4 6 8 10 12 14
Neutrino beam Neutrino beam Neutrino beam Antineutrino beam
contained-vertex 120583
nonfiducial 120583contained-vertex 120583
contained-vertex 120583 336 times 1020 POT
(a)
0
20
40
60
0
10
20
30
0
10
20
30
0
5
10
15
20
25
MINOS dataBest fit oscillationsNo oscillations
NC backgroundCosmic-ray muons
120583 120583 120583 120583
0 1 2 3 4 0 1 2 3 4 0 1 2 3 4 0 1 2 3 4
Even
ts
Even
ts
Even
ts
Even
ts
Atmos contained-vertex 120583 Atmos nonfiducial 120583minus Atmos nonfiducial 120583+3788kton-years
Atmos contained-vertex 120583
log10( (km)E (GeV)) log10( (km)E120583 (GeV))L L log10( (km)E (GeV))L log10( (km)E120583 (GeV))L
(b)
Figure 10 The energy spectra of ]120583and ]
120583CC interactions observed at the FD compared to the expectation with and without oscillation
(a) shows beam-induced neutrinos (b) shows atmospheric neutrinos
with neutrinos alone (the red line in Figure 13) It should benoted that the first MINOS measurement of the antineutrinooscillation parameters released in 2010 [17] yielded a notabletension between the ] and ] oscillation parameters whichwere in agreement only at the 20 confidence levelThis ten-sion was shown to be a statistical fluctuation as the additionof further data brought the ] and ] parameters measurementsinto good agreement [19 20]
5 Electron Neutrino andAntineutrino Appearance
A search for ]119890and ]
119890appearance in the ]
120583and ]
120583beams
enables a measurement of the mixing angle 12057913 It is critical
to know the level of background to the ]119890sample in the
FD The energy spectrum of background events measured inthe ND is used to predict the spectrum expected in the FDHowever the background consists of three components NCinteractions CC ]
120583and ]
120583interactions and the intrinsic ]
119890
component in the beam The relative contribution betweenthe ND and FD is different for all of these components sincethey are affected differently by oscillation and the kinematicsof the production in the beam are different Therefore each
backgroundmust be individually measuredTheNuMI beamcan be configured to produce neutrino beams of varyingenergy by altering the current passing through the magnetichorns and changing the relative positions of the target andhorns Between these different beam configurations therelative contributions of the three background componentschange in a well-understood way as shown in Figure 15By comparing the ND data to the simulation in the threedifferent beam configurations shown in the figure the contri-butions of the three background components can be extracted[71]
Using the data-driven background extraction procedurea total of 1277 background events are expected at the FDin the neutrino-dominated beam and 175 events in theantineutrino-enhanced beam In the data 152 and 20 eventsare observed respectively Figure 16 shows the energy spectraof these events divided into bins of the library eventmatchingdiscriminant variable Although CC ]
119890and ]119890events cannot
be separated on an event-by-event basis the change inthe relative numbers of neutrino and antineutrino inter-actions between the neutrino-dominated and antineutrino-enhanced beams is well knownThis allows separate limits tobe placed on the rates of ]
120583rarr ]119890and ]120583rarr ]119890transitions
on a statistical basis
10 Advances in High Energy PhysicsRa
tio to
no
osci
llatio
ns
05
1
15
2
25
0 10 15 20 30 50
MINOS far detector data
5Reconstructed 120583 energy (GeV)
1071 times 1020 POT
Prediction Δm2 = 241 times 10minus3eV2
Low energy beam 120583-mode
Figure 11 The ratio of the observed ]120583energy spectrum to the
expectation in the case of no oscillation in the neutrino-dominatedbeam The black points show the data the blue line shows the bestfit to the data
075 080 085 090 095 10015
20
25
30
35
40
90 CL68 CL
90 CL
sin2(2120579)
|Δm
2|(10minus3eV
2)
MINOS 3788 kt-yr atmospheric
336 times 1020 POT 120583 modeSuper-K zenith anglelowast
Super-K LElowast
T2Klowastlowast
lowastNeutrino 2012lowastlowastPRD 85 031103(R) (2012)
1071 times 1020 POT 120583 mode
Figure 12 The allowed regions for the atmospheric oscillationparameters |Δ1198982| and sin2(2120579) assuming identical neutrino andantineutrino oscillation parametersTheMINOS result is comparedto measurements from Super-Kamiokande [61] and T2K [62]
The data are fit to extract a measurement of 12057913 The
resulting measurement is shown in Figure 17 The measuredvalue of 120579
13depends on the CP violating phase 120575 which
directly affects the ]119890and ]
119890appearance probabilities and
themass hierarchy which affects the appearance probabilitiesthrough the interactions of the neutrinos with the matter in
MINOS 120583 disappearance1071 times 1020 POT 120583 mode336 times 1020 POT mode3788kt-yr atmospheric
90 CL120583120583120583 + 120583
120583120583120583 + 120583
Best fit
sin2(2120579) or sin2(2120579)
(|Δm
2|
or Δ
m2|)
(10minus3eV
2)
075 080 085 090 095 100
20
25
30
35
120583
|Figure 13 The allowed region for antineutrino oscillation param-eters (blue line) compared to the region measured with neutrinosalone (red line) and the region measured using both neutrinos andantineutrinos under the assumption they have the same parameters(black line)
20
25
30
20 25 30
|Δm
2| (10
minus3eV
2)
|Δm2| (10minus3eV2)
68 CL|Δm2| = |Δm2|
MINOS 120583 disappearance1071 times 1020 POT 120583 mode336 times 1020 POT mode3788kt-yr atmospheric
90 CLBest fit
120583
Figure 14 A comparison of the measured limits on the masssplittings of neutrinos and antineutrinos
the Earthrsquos crust Assuming a normal mass hierarchy 120575 = 0and 120579
23lt 1205874 MINOS measures 2sin2(2120579
13)sin2(120579
23) =
0051+0038
minus0030 Assuming an inverted mass hierarchy 120575 = 0
and 12057923
lt 1205874 MINOS measures 2sin2(212057913)sin2(120579
23) =
0093+0054
minus0049 This measurement is consistent with the results
from reactor neutrino searches [72ndash74] and the T2K experi-ment [75]
This MINOS measurement is the first ever search for ]119890
appearance in a long-baseline ]120583beam and the first search
Advances in High Energy Physics 11
Reconstructed energy (GeV)0 6 8
Frac
tion
of ev
ents
0
01
02
03
04
Standard MC
MINOS
2 4
Near detector 2011
NC120583-CCe-CC
(a)
Horn-off MC
Reconstructed energy (GeV)0 6 8
Frac
tion
of ev
ents
0
01
02
03
04 MINOS
2 4
Near detector 2011
NC120583-CCe-CC
(b)
High energy MC
Reconstructed energy (GeV)0 6 8
Frac
tion
of ev
ents
0
01
02
03
04 MINOS
2 4
Near detector 2011
NC120583-CCe-CC
(c)
Figure 15 The contribution of the three components to the background in the ]119890appearance search as simulated in the ND (a) the regular
(low energy) beam data (b) with no current in the NuMI focusing horns (c) a high energy beam configuration
for ]119890and ]119890appearance with significant matter effects Both
of these effects provide some sensitivity to the neutrinomass hierarchy and CP violation when the MINOS data iscompared to the measurements made by reactor neutrinosearches [72ndash74] (we have calculated a limit of sin2(2120579
13) =
0098 plusmn 0013 from the reactor data at the time of analysis)The sensitivity of MINOS to the mass hierarchy and CPviolation is modest but this contributes to the first analysisof the type that will be used by all future long-baselineexperiments The resulting values of the likelihood by whichMINOS disfavours various values of these parameters areshown in Figure 18 [76]
6 Search for Sterile Neutrino Mixing UsingNeutral-Current Interactions
The energy spectrum of NC interactions in the FD should beunchanged by standard neutrino oscillationThe existence ofone or more sterile neutrino flavours ]
119904 could cause a deficit
in the observed NC interaction rate As with all the MINOSoscillation analyses the energy spectrum of NC interactionsobserved in the ND (which was shown in Figure 8) is usedto predict the spectrum expected at the FD [77] The FDexpectation is shown in Figure 19 with the dashed blue linetaking into account ]
119890appearance corresponding to 120579
13=
115∘ (at the limit set by CHOOZ [78] and a little above
the current accepted value [29 72ndash75] this analysis usesonly the first 707 times 10
20 protons on target of data andwas performed before the recent positive measurements ofa nonzero 120579
13) The data are also shown in the figure and
are in good agreement with the expectation confirming thestandard model of neutrino oscillation This agreement canbe quantified using a test statistic 119877
119877 =119873data minus 119861CC
119878NC (7)
where 119873data is the number of events observed 119861CC is thepredicted background of CC interactions and 119878NC is the
predicted number of NC interactions A value of 119877 = 101 plusmn
006(stat) plusmn 005(syst) is obtained (over the full energy range0ndash120GeV) which is in good agreement with the expectationof 119877 = 1 in the case of no mixing with sterile neutrinos
The data are analysed with a model that assumes a singlesterile neutrino flavour mixing through the addition of afourth neutrino mass state119898
4≫ 1198983 This introduces a mass
splitting Δ119898243
with magnitude O(1 eV2) such that no oscil-lation-induced change to the event rate is observed at theND and the oscillatory energy dependence of the induceddepletion at the FD is so rapid that an overall uniform deple-tion is observed once the energy resolution of the detectors isaccounted forThismodel introduces three additionalmixingangles 120579
14 12057924 and 120579
34 MINOS is insensitive to 120579
14but sets
limits of 12057924= (00
+5
minus00)∘ and 120579
34= (00
+25
minus00)∘ These limits are
evaluated assuming 12057913at the CHOOZ limit
The limit on the coupling of sterile to active neutrinos canbe quantified by defining 119891
119904 the fraction of disappearing ]
120583
which have oscillated into ]119904
119891119904=
119875]120583rarr ]119904
1 minus 119875]120583rarr ]120583
(8)
For the model used in which 1198984≫ 119898
3 119891119904is evaluated
at 14 GeV the energy of maximal ]120583disappearance To
determine the limit on 119891119904 a large number of test values
are chosen of the mixing angles 12057924 12057934 and 120579
23 from
Gaussian distributions according to the measured values and1120590 uncertainties given above (with 120579
23constrained from the
measurements with CC ]120583interactions) 119891
119904is calculated for
each case and the value of 119891119904that is larger than 90 of the
test cases represents the limit MINOS limits 119891119904lt 040 at the
90 confidence level
7 The Future MINOS+
The MINOS experiment has made some very importantcontributions to our understanding of neutrino oscillation
12 Advances in High Energy Physics
Reconstructed energy (GeV)
Reconstructed energy (GeV)
Even
ts
30
0
10
20
Even
ts
30
0
10
20
Even
ts
30
0
10
20
2 4 6 8
2 4 6 8
Reconstructed energy (GeV)2 4 6 8
06 lt 120572LEM lt 07
MINOS far detector data
07 lt 120572LEM lt 08
120572LEM gt 08
mode
mode
mode
e CC signal
e CC signalBackgroundData
(a)
Even
ts
Reconstructed energy (GeV)2 4 6 8
Reconstructed energy (GeV)2 4 6 8
Reconstructed energy (GeV)2 4 6 8
06 lt 120572LEM lt 07
MINOS far detector data
Merged for fit
07 lt 120572LEM lt 08
120572LEM gt 08
mode
mode
mode
8
6
4
2
0
Even
ts
8
6
4
2
0
Even
ts
8
6
4
2
0
e CC signal
e CC signalBackgroundData
5ndash8GeV bins
(b)
Figure 16 The CC ]119890(a) and ]
119890(b) candidate events selected in the FD compared to the expectation without any ]
119890appearance (red) and
with the best fit for 12057913(purple) The events are divided into bins of the library event matching discriminant variable
Advances in High Energy Physics 13
20
15
10
05
000 01 02 03 04
2sin2(212057913)sin212057923
Δm2 gt 0
sin
120575(120587)
(a)
20
15
10
05
000 01 02 03 04
2sin2(212057913)sin212057923
MINOS best fit 12057923 lt 1205874
MINOS best fit 12057923 gt 1205874
Δm2 lt 0
MINOS
106 times 1020 POT -mode33 times 1020 POT -mode
68 CL 12057923 lt 1205874
90 CL 12057923 lt 1205874
120575(120587)
(b)
Figure 17 The allowed regions for 2sin2(212057913)sin2(120579
23)
120575(120587)
Δm2 gt 0 12057923 gt 1205874
Δm2 gt 0 12057923 lt 1205874
Δm2 lt 0 12057923 gt 1205874Δm2 lt 0 12057923 lt 1205874
3
2
1
00 1 1505 2
MINOS
90 CL
68 CL
minus2Δ
(L)
ln
Figure 18 The values of likelihood 119871 by which various values oftheCP violating parameter 120575 the mass hierarchy and the octant of12057923are disfavouredThis analysis uses MINOS data and information
from reactor neutrino measurements of 12057913[72ndash74]
physics and has finished taking data with the low energybeam for which it was designed However the experimentwill continue taking data and producing new results for thenext few years as MINOS+ [79] The NuMI beam is being
20
2018161410 12
Far detector data
Even
ts (G
eV)
00 2 4 6 8
40
60
80
100
120
140
12057913 = 0∘
12057913 = 115∘ 120575 = 120587 Δm232 gt 0
120583 CC background|Δm2
32| = 232 times 10minus3eV2
Ereco (GeV)
sin2212057923 = 1
Figure 19 The black dots show the energy spectrum of NCinteractions observed in the far detector The red lines show theexpectation in the case of no sterile neutrinos and 120579
13= 0 the blue
dashed line shows the same expectation with 12057913= 115
∘
upgraded to a higher energy and intensity for the NO]Aexperiment the far detector of which will sit 14 mrad offaxisNO]A will receive a narrow-band beam peaking at around2GeV which is ideal for searching for ]
119890appearance since
the background seen in MINOS from NC interactions ofhigh energy neutrinos will be heavily reduced Figure 20shows that the MINOS FD will see an intense ]
120583beam
14 Advances in High Energy Physics
1000
500
00 5 10 15 20
E (GeV)
MINOS+NOAMINOS
Preliminary
Simulated beam54 kton 6 times 1020 POT
120583CC
even
ts (G
eV)
Figure 20 The ]120583energy spectrum that will be observed by the
MINOS+ FD compared to the spectra observed by MINOS andNO]A
peaking at around 7GeV In this configuration MINOS+ willobserve around 4000 CC ]
120583interactions in the FD each
year unprecedented statistics for a long-baseline oscillationexperimentThis will offer a unique high precision test of thethree-flavour oscillation paradigm
MINOS+ will be able to make a very sensitive searchfor the sterile neutrinos suggested by the LSND [80] andMiniBooNE [81 82] data and by some interpretations ofreactor neutrino data [83] This search will cover more thanthree orders of magnitude in the mass splitting between thesterile and active neutrinos The signal that MINOS+ willsearch for is illustrated in Figure 21 Figure 21(a) illustratesthe increase in statistical precision thatMINOS+will provideon the ratio of the observed CC ]
120583interaction rate to
that expected without oscillations Figure 21(b) shows howthis ratio is modified if a sterile neutrino exists and mixeswith the active neutrinos an additional deficit of muonneutrino interactions occurs in the higher energy region ofthe spectrum In the model assumed here which introducesa single sterile neutrino state three new mixing angles areintroduced 120579
14 12057924 and 120579
34 An additional mass splitting
Δ1198982
43is also introduced The position in energy of the
additional deficit is governed by the value of the new masssplittingThemagnitude of the additional deficit in the CC ]
120583
interaction rate is governed primarily by the size of 12057924 this is
in comparison to short-baseline searches for ]119890disappearance
from reactors which are governed by 12057914and searches for ]
119890
appearance in ]120583beamswhich are governed by a combination
of 12057914
and 12057924 A detailed explanation of the global effort to
search for sterile neutrinos can be found in [84]The sensitivity of the MINOS+ experiment when com-
bined with the Bugey reactor neutrino data [85] is shown in
MINOS+ simulation
MINOS 1071 times 1021 POT06 times 1021 POT12 times 1021 POT18 times 1021 POT
120583su
rviv
al p
roba
bilit
y
Neutrino energy (GeV)0 5 10 15
15
1
05
0
(a)
P(
120583rarr
120583)
No sterile neutrinosΔm2
43 = 2 times 10minus2eV2 sin2(212057924) = 02
0 5 10 15 20
1
0
18
06
04
02
Neutrino energy (GeV)
(b)
Figure 21 (a) The black points show the ratio of the observed ]120583
energy spectrum to the expectation in the case of no oscillation inthe neutrino-dominated beam of MINOS The blue region showsthe statistical precision expected from MINOS+ (b) The black lineshows the muon neutrino survival probability in the case of nosterile neutrinos the red line shows how the probability would bemodified by the addition of mixing with a sterile neutrino
Figure 22 MINOS+ has the potential to rule out much of theLSND allowed region MINOS+ will begin taking data in thelate summer of 2013 and will continue taking data for at leasttwo years (Figure 22 assumes two years of data taking with aneutrino-dominated beam)
8 Conclusion
The MINOS experiment was conceived at a time when neu-trino oscillation had only recently been confirmed as thesolution to the problem of neutrino flavour change It has
Advances in High Energy Physics 15
Δm
2
10minus210minus2
10minus1
10minus1
10minus310minus4 1
1
10
102
LSND 90 CLLSND 99 CLKarmen2 90 CLBugey 90 CLlowast
MiniBooNE 90 CLMiniBooNE 99 CLMINOS+ and Bugeycombination 90 CL
sin22120579120583e
lowastGLoBES 2012 fit with new reactor fluxescourtesy of P Huber
Figure 22 The sensitivity of MINOS+ to the existence of sterileneutrinos when combined with data from the Bugey [85] reactorneutrino experiment Δ1198982 is the splitting between the three knownneutrino mass states and a new fourth state 120579
120583119890is the mixing angle
governing ]120583rarr ]119890transitions when a fourth sterile neutrino state
is introduced into the PMNSmixingmatrixThis figure assumes twoyears of MINOS+ running with a neutrino-dominated beam
played a hugely influential role in bringing neutrino oscilla-tion physics into an era of precision measurement MINOSrsquosmeasurement of the largest neutrino mass splitting is themost precise in the world MINOS has made the first directprecision measurement of the corresponding antineutrinoparameters a measurement that promises to remain theworldrsquos most precise for many years And MINOS has playeda role in the discovery of a nonzero value for 120579
13
Now that the value of 12057913is known the neutrino physics
community can move on to determine the neutrino masshierarchy and to search for CP violation in the neutrinosector MINOS has pioneered a number of techniques thatwill be used by future experiments The two-detector setupall important in reducing the impact of systematic uncer-tainties is the design of choice for any new experiment andMINOS has demonstrated methods of using a near detectorto determine the expectation at a far detector MINOS hasperformed the first search for ]
119890appearance in a ]
120583beam
and the first search for ]119890and ]119890appearance with significant
matter effects demonstrating the analysis techniques that willbe used to determine the mass hierarchy and CP violationparameter
In the second half of 2013 MINOS will begin taking dataas the MINOS+ experiment which will make ever more pre-cise tests of the three-flavour neutrino oscillation paradigmand set world-leading limits on the existence of sterileneutrinos This is an exciting future for an experiment thatwith a decade of data taking so far has already created alasting legacy for itself in our understanding of the neutrino
A comparison of themeasured neutrino and antineutrinomass splittings is shown in Figure 14 the difference betweenthe two is constrained to |Δ119898
2| minus |Δ119898
2| = (012
+024
minus026) times
10minus3 eV2
Acknowledgment
The work of the MINOS and MINOS+ collaborations issupported by the US DoE the UK STFC the US NSF theState and University of Minnesota the University of Athensin Greece and Brazilrsquos FAPESP and CNPq The authors aregrateful to the Minnesota Department of Natural Resourcesthe crew of the Soudan Underground Laboratory and thepersonnel of Fermilab for their vital contributions
References
[1] S Wojcicki ldquoLong baseline neutrino oscillation programe inthe United Statesrdquo Nuclear Physics B vol 77 no 1ndash3 pp 182ndash186 1999 Proceedings of the 18th International Conference onNeutrino Physics and Astrophysics (Neutrino rsquo98) TakayamaJapan June 1998
[2] R Davis Jr D S Harmer and K C Hoffman ldquoSearch forneutrinos from the sunrdquo Physical Review Letters vol 20 no 21pp 1205ndash1209 1968
[3] A I Abazov O L Anosov E L Faizov et al ldquoSearch forneutrinos from sun using the reactionGa-71 (electron-neutrinoe-) Ge-71rdquo Physical Review Letters vol 67 pp 3332ndash3335 1991
[4] P Anselmann W Hampel G Heusser et al ldquoSolar neutrinosobserved by GALLEX at gran sassordquo Physics Letters B vol 285no 4 pp 376ndash389 1992
[5] M Aglietta G Battistoni E Bellotti et al ldquoExperimentalstudy of atmospheric neutrino flux in the NUSEX experimentrdquoEurophysics Letters vol 8 no 7 article 611 1989
[6] K S Hirata ldquoObservation of a small atmospheric V120583V119890ratio in
Kamiokanderdquo Physics Letters B vol 280 no 1-2 pp 146ndash1521992
[7] R Becker-Szendy C B Bratton D Casper et al ldquoElectron-and muon-neutrino content of the atmospheric fluxrdquo PhysicalReview D vol 46 pp 3720ndash3724 1992
[8] K Daum W Rhode P Bareyre et al ldquoDetermination ofthe atmospheric neutrino spectra with the frejus detectorrdquoZeitschrift fur Physik C vol 66 no 3 pp 417ndash428 1995
[9] S Ahlen M Ambrosio R Antolini and G Auriemma ldquoAtmo-spheric neutrino flux measurement using upgoing muonsrdquoPhysics Letters B vol 357 no 3 pp 481ndash486 1995
[10] WMAllison G J Alner D S Ayres et al ldquoMeasurement of theatmospheric neutrino flavour composition in Soudan 2rdquoPhysicsLetters B vol 391 no 3-4 pp 491ndash500 1997
16 Advances in High Energy Physics
[11] Y Fukuda T Hayakawa E Ichihara et al ldquoEvidence foroscillation of atmospheric neutrinosrdquo Physical Review Lettersvol 81 no 8 pp 1562ndash1567 1998
[12] Q R Ahmad R C Allen T C Andersen et al ldquoMeasurementof charged current interactions produced by solar neutrinos atthe sudbury neutrino observatoryrdquo Physical Review Letters vol87 Article ID 071301 2001
[13] Q R Ahmad R C Allen T C Andersen et al ldquoDirect evidencefor neutrino flavor transformation from neutral-current inter-actions in the sudbury neutrino observatoryrdquo Physical ReviewLetters vol 89 Article ID 011301 6 pages 2002
[14] B Pontecorvo ldquoInverse beta processes and nonconservation oflepton chargerdquo Journal of Experimental and Theoretical Physicsvol 34 pp 172ndash173 1958
[15] V N Gribov and B Pontecorvo ldquoNeutrino astronomy andlepton chargerdquo Physics Letters B vol 28 pp 493ndash496 1969
[16] Z Maki M Nakagawa and S Sakata ldquoRemarks on the unifiedmodel of elementary particlesrdquo Progress of Theoretical Physicsvol 28 no 5 pp 870ndash880 1962
[17] P Adamson C Andreopoulos D J Auty et al ldquoFirst directobservation of muon antineutrino disappearancerdquo PhysicalReview Letters vol 107 no 2 Article ID 021801 2011
[18] P Adamson D J Auty D S Ayres et al ldquoSearch for thedisappearance of muon antineutrinos in the NuMI neutrinobeamrdquo Physical Review D vol 84 no 7 Article ID 071103 6pages 2011
[19] P Adamson D S Ayres C Backhouse et al ldquoImprovedmeasurement of muon antineutrino disappearance inMINOSrdquoPhysical Review Letters vol 108 no 19 Article ID 191801 5pages 2012
[20] P Adamson I Anghel C Backhouse et al ldquoMeasurementof Neutrino and Antineutrino Oscillations Using Beam andAtmospheric Data in MINOSrdquo Physical Review Letters vol 110no 25 Article ID 251801 6 pages 2013
[21] K Anderson B Bernstein D Boehnlein et al ldquoThe NuMIFacility Technical Design Reportrdquo FERMILAB-DESIGN-1998-01 1998
[22] D G Michael P Adamson T Alexopoulos et al ldquoObservationof muon neutrino disappearance with the MINOS detectors inthe NuMI neutrino beamrdquo Physical Review Letters vol 97 no19 Article ID 191801 6 pages 2006
[23] P Adamson C Andreopoulos K E Arms et al ldquoStudy ofmuon neutrino disappearance using the fermilab main injectorneutrino beamrdquo Physical Review D vol 77 no 7 Article ID072002 34 pages 2008
[24] P Adamson C Andreopoulos K E Arms et al ldquoMeasurementof neutrino oscillations with theMINOS detectors in the NuMIbeamrdquo Physical Review Letters vol 101 no 13 Article ID 1318025 pages 2008
[25] P Adamson C Andreopoulos R Armstrong et al ldquoMea-surement of the neutrino mass splitting and flavor mixing byMINOSrdquo Physical Review Letters vol 106 no 18 Article ID181801 6 pages 2011
[26] P Adamson C Andreopoulos K E Arms et al ldquoSearch formuon-neutrino to electron-neutrino transitions in MINOSrdquoPhysical Review Letters vol 103 no 26 Article ID 261802 5pages 2009
[27] PAdamsonCAndreopoulosD J Auty et al ldquoNew constraintsonmuon-neutrino to electron-neutrino transitions inMINOSrdquoPhysical ReviewD vol 82 no 5 Article ID 051102 6 pages 2010
[28] P Adamson D J Auty D S Ayres et al ldquoImproved search formuon-neutrino to electron-neutrino oscillations in MINOSrdquoPhysical Review Letters vol 107 no 18 Article ID 181802 6pages 2011
[29] P Adamson I Anghel C Backhouse et al ldquoElectron neutrinoand antineutrino appearance in the full MINOS data samplerdquoPhysical Review Letters vol 110 no 17 Article ID 171801 6 pages2013
[30] P Adamson C Andreopoulos K E Arms et al ldquoSearch foractive neutrino disappearance using neutral-current interac-tions in theMINOS long-baseline experimentrdquo Physical ReviewLetters vol 101 no 22 Article ID 221804 5 pages 2008
[31] P Adamson C Andreopoulos D J Auty et al ldquoSearch for ster-ile neutrino mixing in the MINOS long-baseline experimentrdquoPhysical Review D vol 81 no 5 Article ID 052004 18 pages2010
[32] P Adamson D J Auty D S Ayres et al ldquoActive to sterileneutrino mixing limits from neutral-current interactions inMINOSrdquo Physical Review Letters vol 107 no 1 Article ID011802 5 pages 2011
[33] Z Pavlovic Observation of disappearance of muon neutrinos inthe NuMI beam [PhD thesis] University of Texas at AustinAustin Tex USA 2008
[34] F Ballarini G Battistoni M Campanella et al ldquoThe FLUKAcode an overviewrdquo Journal of Physics vol 41 article 151 2006
[35] S Agostinelli J Allison K Amako et al ldquoGEANT4mdasha sim-ulation toolkitrdquo Nuclear Instruments and Methods in PhysicsResearch A vol 506 no 3 pp 250ndash303 2003
[36] G Battistoni F Cerutti A Fasso et al ldquoThe FLUKA codedescription and benchmarkingrdquo in Proceedings of the HadronicShower Simulation Workshop vol 896 of AIP Conference Pro-ceedings pp 31ndash49 Batavia Ill USA September 2006
[37] D G Michaele P Adamson T Alexopoulos et al ldquoThe mag-netized steel and scintillator calorimeters of the MINOS exper-imentrdquoNuclear Instruments and Methods in Physics Research Avol 596 no 2 pp 190ndash228 2008
[38] I E Stockdale A Bodek F Borcherding N Giokaris et alldquoLimits on muon-neutrino oscillations in the mass range 30 lt9987791198982lt 1000 eV2c4 rdquo Physical Review Letters vol 52 no 16 pp
1384ndash1388 1984[39] F Dydak G J Feldman C Guyot et al ldquoA search for V
120583
oscillations in the9987791198982 range 03ndash90 eV2 rdquo Physics Letters B vol134 no 3-4 pp 281ndash286 1984
[40] F Bergsma J Dorenbosch M Jonker et al ldquoA searchfor oscillations of muon neutrinos in an experiment withLEcong07 kmGeVrdquo Physics Letters B vol 142 no 1-2 pp 103ndash1101984
[41] M H Ahn E Aliu S Andringa et al ldquoMeasurement ofneutrino oscillation by the K2K experimentrdquo Physical ReviewD vol 74 no 7 Article ID 072003 39 pages 2006
[42] P Adamson T Alexopoulos W W M Allison et al ldquoFirstobservations of separated atmospheric V
120583and ]
120583events in the
MINOS detectorrdquo Physical Review D vol 73 no 7 Article ID072002 2006
[43] P Adamson C Andreopoulos K E Arms et al ldquoCharge-separated atmospheric neutrino-inducedmuons in theMINOSfar detectorrdquo Physical ReviewD vol 75 no 9 Article ID 09200314 pages 2007
[44] P Adamson C Backhouse G Barr et al ldquoMeasurements ofatmospheric neutrinos and antineutrinos in the MINOS fardetectorrdquo Physical Review D vol 86 no 5 Article ID 05200720 pages 2012
Advances in High Energy Physics 17
[45] M A Kordosky Hadronic interactions in the MINOS detectors[PhD thesis] University of Texas at Austin Austin Tex USA2004
[46] P L Vahle Electromagnetic interactions in the MINOS detectors[PhD thesis] University of Texas at Austin Austin Tex USA2004
[47] C Backhouse Measuring neutrino oscillation parameters using]120583disappearance inMINOS [PhD thesis] University of Oxford
Oxford UK 2011[48] T M Cover and P E Hart ldquoNearest neighbor pattern classifi-
cationrdquo IEEE Transactions on Information Theory vol 13 no 1pp 21ndash27 1967
[49] R Ospanov A measurement of muon neutrino disappearancewith the MINOS detectors and NuMI beam [PhD thesis]University of Texas at Austin Austin Tex USA 2008
[50] J S Marshall A study of muon neutrino disappearance with theMINOS detectors and the NuMI neutrino beam [PhD thesis]University of Cambridge Cambridge UK 2008
[51] J P OchoaA search formuon neutrino to electron neutrino oscil-lations in the MINOS Experiment [PhD thesis] The CaliforniaInstitute of Technology Pasadena Calif USA 2009
[52] R TonerMeasuring 12057913via muon neutrino to electron neutrino
oscillations in the MINOS experiment [PhD thesis] Universityof Cambridge Cambridge UK 2011
[53] A Holin Electron neutrino appearance in the MINOS experi-ment [PhD thesis] University College London London UK2010
[54] J Boehm Measurement of electron neutrino appearance withthe MINOS experiment [PhD thesis] Harvard UniversityCambridge Mass USA 2009
[55] G Tinti Sterile neutrino oscillations in MINOS and hadronproduction in pC collisions [PhD thesis] University of OxfordOxford UK 2010
[56] J J EvansMeasuring antineutrino oscillations with the MINOSexperiment [PhD thesis] University of Oxford Oxford UK2008
[57] S J ColemanAmeasurement of neutrino oscillations withmuonneutrinos in the MINOS experiment [PhD thesis] College ofWilliam ampMary Williamsburg Va USA 2011
[58] J S Mitchell Measuring ]120583disappearance with the MINOS
experiment [PhD thesis] University of Cambridge CambridgeUK 2011
[59] A McGowan Observation of deficit in NuMI neutrino-inducedrock and non-fiducial muons in MINOS far detector andmeasurement of neutrino oscillation parameters [PhD thesis]University of Minnesota Minneapolis Minn USA 2007
[60] M StraitMeasurement of neutrino oscillation parameters usinganti-fiducial charged current events in MINOS [PhD thesis]University of Minnesota Minneapolis Minn USA 2010
[61] Y Itow ldquoAtmospheric neutrinosmdashresults from running exper-imentsrdquo in Proceedings of the 25th International Conference onNeutrino Physics and Astrophysics (Neutrino rsquo12) Kyoto JapanJune 2012
[62] K Abe N Abgrall Y Ajima et al ldquoFirst muon-neutrinodisappearance study with an off-axis beamrdquo Physical Review Dvol 85 no 3 Article ID 031103 8 pages 2012
[63] K Nakamura ldquoReview of particle physicsrdquo Journal of Physics Gvol 37 Article ID 075021 2010
[64] L Wolfenstein ldquoNeutrino oscillations in matterrdquo PhysicalReview D vol 17 no 9 pp 2369ndash2374 1978
[65] J W F Valle ldquoResonant oscillations of massless neutrinos inmatterrdquo Physics Letters B vol 199 no 3 pp 432ndash436 1987
[66] M C Gonzalez-Garcia M M Guzzo P I Krastev et alldquoAtmospheric neutrino observations and flavor changing inter-actionsrdquo Physical Review Letters vol 82 no 16 pp 3202ndash32051999
[67] A Friedland C Lunardini and M Maltoni ldquoAtmosphericneutrinos as probes of neutrino-matter interactionsrdquo PhysicalReview D vol 70 no 11 Article ID 111301 2004
[68] Z IsvanAntineutrino oscillations and a Search for non-standardInteractions with the MINOS [PhD thesis] University of Pitts-burgh Pittsburgh Pa USA 2012
[69] W A Mann D Cherdack W Musial and T Kafka ldquoApparentmultiple 998779119898
32
2 in ]120583and V
120583survival oscillations from nonstan-
dard interactionmatter effectrdquo Physical Review D vol 82 no 11Article ID 113010 8 pages 2010
[70] J Kopp P A N Machado and S J Parke ldquoInterpretation ofMINOS data in terms of nonstandard neutrino interactionsrdquoPhysical Review D vol 82 no 11 Article ID 113002 12 pages2010
[71] J A B Coelho Investigacao de mecanismos alternativos aoscilacao de neutrinos no experimentos MINOS [PhD thesis]Universidade Estadual de Campinas Sao Paulo Brazil 2012
[72] F P An Q An J Z Bai A B Balantekin et al ldquoImprovedmeasurement of electron antineutrino disappearance at DayaBayrdquo Chinese Physics C vol 37 Article ID 011001 21 pages 2013
[73] J K Ahn S Chebotaryov J H Choi et al ldquoObservationof reactor electron antineutrinos disappearance in the RENOexperimentrdquo Physical Review Letters vol 108 Article ID 1918026 pages 2012
[74] Y Abe C Aberle J C dos Anjos et al ldquoReactor electronantineutrino disappearance in the Double Chooz experimentrdquoPhysical Review D vol 86 Article ID 052008 2012
[75] K Abe N Abgrall H Aihara et al ldquoEvidence of electronneutrino appearance in a muon neutrino beamrdquo PhysicalReview D vol 88 no 3 Article ID 032002 41 pages 2013
[76] A Schreckenberger Electron neutrino and antineutrino appear-ance in the MINOS detector [PhD thesis] University of Min-nesota Minneapolis Minn USA 2013
[77] D J Koskinen MINOS sterile neutrino search [PhD thesis]University College London London UK 2009
[78] M Apollonio A Baldini C Bemporad et al ldquoSearch forneutrino oscillations on a long base-line at the CHOOZ nuclearpower stationrdquoTheEuropean Physical Journal C vol 27 pp 331ndash374 2003
[79] G Tzanankos M Bishai M Diwan et alMINOS+ a proposalto FNAL to run MINOS with the medium energy NuMI beam[PhD thesis] University of Athens Athens Greece 2011
[80] A Aguilar L B Auerbach R L Burman et al ldquoEvidence forneutrino oscillations from the observation of ]
119890e appearance
in a ]120583beamrdquo Physical Review D vol 64 Article ID 112007 22
pages 2001[81] A A Aguilar-Arevalo C E Anderson S J Brice et al ldquoSearch
for electron antineutrino appearance at the Δ119898 sim 1 eV2 ScalerdquoPhysical Review Letters vol 103 no 11 Article ID 111801 2009
[82] A A Aguilar-Arevalo C E Anderson A O Bazarko et alldquoImproved search for V
120583rarr V119890oscillations in the MiniBooNE
experimentrdquo Physical Review Letter vol 110 no 10 Article ID161801 2013
[83] GMentionM Fechner T Lasserre et al ldquoReactor antineutrinoanomalyrdquo Physical Review D vol 83 Article ID 073006 20pages 2011
18 Advances in High Energy Physics
[84] KNAbazajianMAAcero S KAgarwalla et al ldquoLight sterileneutrinos a white paperrdquo httparxivorgabs12045379
[85] B Achkar R Aleksan M Avenier et al ldquoSearch for neutrinooscillations at 15 40 and 95meters from a nuclear power reactorat Bugeyrdquo Nuclear Physics B vol 434 no 3 pp 503ndash532 1995
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
High Energy PhysicsAdvances in
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
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FluidsJournal of
Atomic and Molecular Physics
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Advances in Condensed Matter Physics
OpticsInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
AstronomyAdvances in
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Superconductivity
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Statistical MechanicsInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
GravityJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Physics Research International
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Computational Methods in Physics
Journal of
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Soft MatterJournal of
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PhotonicsJournal of
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Journal of
Biophysics
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ThermodynamicsJournal of
6 Advances in High Energy Physics
CCNC separation parameter
Low energy beamDataMC expectation
NC background
Even
ts10
16PO
T
10
1
10minus1
10minus2
0 02 04 06 08 1
(a)
Reconstructed neutrino energy (GeV)
0
02
04
06
08
1
NC contamination
Far detector fiducial onlyCC selection efficiency
0 2 4 6 8 10
Effici
ency
con
tam
inat
ion
(b)
Figure 6 (a) The discrimination variable used to separate ]120583CC interactions from hadronic backgrounds Events with a parameter value
greater than 03 are selected as ]120583CC interactions (b) The efficiency and background contamination of the selected ]
120583CC sample in the far
detector
antineutrino-enhanced beams When performing a directmeasurement of the antineutrino oscillation parameters anadditional selection cut is made requiring the charge of themuon track to be positiveThis uses the direction of curvatureof themuon asmeasured by aKalman Filter algorithm [50] Afurther sample of ]
120583CC interactions is obtained from the 7
]120583component in the neutrino-dominated beamThis sample
contains a significant background of ]120583events in which a 120583minus
has been identified with the incorrect charge often at lowenergies where the muon undergoes significant scatteringTherefore a much stricter set of selection criteria are appliedto purify this ]
120583sample [18]
32 Selection of Charged-Current ]119890Interactions The selec-
tion of ]119890CC interactions focuses on identifying the dense
showers from the electromagnetic interaction of the electronrather than the much more diffuse hadronic showers Theprimary background comes from purely hadronic showerswhich can have a denser than average energy depositparticularly in the presence of a neutral pion decaying tophotons Once a set of shower-like events in the signalregion of 1ndash8GeV has been obtained a pattern matchingapproach called library event matching is used to identifythe interactions most likely to be ]
119890CC [51 52] Each event
in the data is compared to a library of 5 times 107 simulated
signal and background events its similarity to the libraryevents is quantified by comparing the pattern of energydeposits in each scintillator strip excited by the shower wherethe energy deposit is quantified by the charge recorded onthe photomultiplier tube For an arbitrary energy depositthe mean expected charge on a photomultiplier tube willbe some value 120582 The probability of observing an amountof charge 119899 is then a Poisson distribution 119875(119899 | 120582) Thelikelihood L of a data event corresponding to the same
physical shower topology as a simulated library event cantherefore be calculated as
logL =
119873strips
sum
119894=1
log [intinfin
0
119875 (119899119894
data | 120582) 119875 (119899119894
lib | 120582) d120582] (6)
where 119894 represents the 119894th scintillator strip in the showerUsing this definition of the likelihood the 50 library eventsare identified that best match the data eventThree quantitiesare calculated from this set of 50 best-matching library eventsthe fraction of the events that are true ]
119890CC events the
average inelasticity of the true ]119890CC events and the average
fraction of charge that overlaps between the data event andeach ]
119890CC library event These three quantities are input to
a neural network which calculates a classification variableshown in Figure 7 Events with a classification variable valueabove 06 are selected for analysis this value was chosen tomaximise the sensitivity to ]
119890and ]119890appearance
The efficiency of the ]119890CC selection is estimated from
the data rather than relying totally on the simulation Toobtain a pure sample of true hadronic showers a sampleof well-identified ]
120583CC events is selected and the energy
depositions corresponding to the muon track are removed[53]The simulated energy depositions of an electron are theninserted [54] providing a realistic sample of ]
119890CC events
Using thismethod the ]119890CC identification efficiency is found
to be (574 plusmn 28) in the neutrino-dominated beam and(633 plusmn 31) in the antineutrino-enhanced beam
33 Selection of Neutral-Current Interactions The signal of anNC interaction is a diffuse hadronic shower ]
120583CC interac-
tions also produce hadronic showers and if the inelasticityis high the tell-tale muon track may not visibly extend pastthe shower To purify a sample of NC interactions a simple
Advances in High Energy Physics 7
sin2(212057913) = 01
Δm232 gt 0 120575cp = 0 12057923 =
120587
4
Background
MINOS far detector80
60
40
20
00 01 02 03 04 05 06 07 08 09 1
LEM discriminant
Signal times10
Even
ts8
2times10
20PO
T
(a)
LEM discriminant
Even
ts10
19PO
T
DataMonte Carlo
MINOS near detector8000
6000
4000
2000
00 01 02 03 04 05 06 07 08 09 1
(b)
Figure 7 (a) The library event matching discriminant showing the expected distribution for background and CC ]119890signal events in the far
detector in the neutrino-dominated beam Note that the signal simulated for sin2(212057913) = 01 120575 = 0 and a normal mass hierarchy has been
scaled up by a factor of ten for visibility (b)The same discriminant as observed in the near detector compared with the simulated expectation
Near detector dataMonte Carlo prediction
20
10
30
50
2018161410 120
0 2 4 6 8
40
60
120583 CC background
Ereco (GeV)
104
even
ts (G
eV)
Figure 8 The sample of events identified as NC interactions in thenear detector
cut-based approach is taken [55] events are classified asNC-like if the event contains no reconstructed track or ifthe track extends no more than six planes past the end ofthe shower The resulting distribution of NC interactions inthe near detector is shown in Figure 8 The NC identificationefficiency is 89 with 61 purity This selection will identify97 of ]
119890CC interactions as NC events therefore an analysis
of NC interactions in the FD must account for the ]119890
appearance caused by a nonzero 12057913
34 Selection of Atmospheric Neutrinos Atmospheric neu-trino interactions are selected out of any activity seen in
the FD outside of the 10 120583s periods when the NuMI beamis active [44] The oscillation signal is contained in the ]
120583
CC interactions and as with the beam-induced interactionsthese are identified by the presence of a muon track The FDbegan taking data with atmospheric neutrinos in July 2003two years before the NuMI beam began running
The FD has a single-hit timing resolution of 25 ns Thistiming information is used to determine the direction inwhich the detector activity is traveling Any downwardstraveling activity is required to begin well inside the detec-tor to eliminate cosmic muons entering from above Allupwards or horizontally traveling activity is almost certainto be neutrino-induced since no other particle can survivethrough the many kilometres of rock All activity with azenith angle of cos 120579
119911lt 014 is defined as horizontal or down-
going this corresponds to an overburden of at least 14 kmwater equivalent
From this sample of neutrino-induced activity all eventswith a track crossing at least eight planes are designatedtrack-like all events with only shower-like activity crossing atleast four planes are designated shower-like These track-likeand shower-like samples are used in the neutrino oscillationmeasurementsThe track-like sample contains the oscillationsignal of ]
120583disappearance The shower-like sample contains
mainly NC interactions and ]119890and ]
119890CC interactions it
shows little oscillation signal but is very important for settingthe normalization of the atmospheric neutrino flux
4 Muon Neutrino andAntineutrino Disappearance
The atmospheric oscillation parameters |Δ1198982| and sin2(2120579)aremeasured by observing and fitting the energy dependenceof ]120583and ]
120583disappearance To minimise the impact of
8 Advances in High Energy Physics
20
40
60
80
100
120
0 10 15 20 30 50
Even
tstimes10
4(G
eV)
MINOS near detector dataMCMC uncertaintyNC background
MINOS near detectorLow energy beam 120583-mode729 times 1020 POT
Reconstructed 120583 energy (GeV)5
Figure 9 The energy spectrum of ]120583CC interactions observed in
the ND compared to the simulation
systematic uncertainties the energy spectra of the ]120583and
]120583CC interactions observed in the ND (shown in Figure 9
for the neutrino-dominated beam) are used to predict thespectrum at the FD in the absence of oscillation [23 56]The neutrino energy spectra at the ND and FD are notidentical the ND subtends a relatively large angle to thebeam so for each pion or kaon a range of decay anglescan produce a neutrino that passes through the detectorcorresponding to a range of neutrino energies However theFD is effectively a point when viewed from the neutrinoproduction location so a single decay angle for each hadrontherefore a single neutrino energy contributes to the fluxTo take this difference into account the hadron-decay kine-matics are encoded into a beam transfer matrix that convertsthe observed ND flux into a predicted FD flux Once theND data has been used in this way the most importantsystematic uncertainties are those that can affect the twodetectors differently primarily reconstruction efficienciesand miscalibrations of the neutrino energy measurementin the detectors [57] These uncertainties are included inthe fit that extracts the oscillation parameters [58] Theuncertainty on the reconstruction efficiency is modeled as a16 uncertainty on the relative rate of events between theND and FD The uncertainty on the measurement of muonenergy has two components that are fully correlated betweenthe detectors a 2 uncertainty on energies measured fromrange and a 3 uncertainty on energies measured fromthe curvature in the magnetic field The uncertainty in thehadronic energy measurements also has two componentsAn uncertainty arising from shower modeling uncertaintiesand calibration is fully correlated between the detectorsand is parameterized as (66 + 35119890119864shw14GeV) The secondcomponent is uncorrelated between the detectors and is 19
in theND and 11 in the FD this is dominated by calibrationuncertainties
The top row of Figure 10 shows the predicted spectra of]120583and ]120583CC interactions from the neutrino-dominated and
antineutrino-enhanced beams at the FD along with the dataIn the neutrino-dominated beam an additional sample isused consisting of neutrinos interacting outside the fiducialvolume of the detector and in the rock surrounding thedetector [59 60] This nonfiducial sample consists mainlyof high energy neutrinos and has significantly lower res-olution as not all the energy is contained in the detectorhowever it does contain some oscillation information Intotal 8100 reconstructed neutrino events are used in theanalysis without oscillations 9471 would be expected Inall samples a clear energy-dependent deficit of ]
120583and
]120583interactions is observed The ratio of the data to the
expectation for the ]120583interactions in the neutrino-dominated
beam is shown in Figure 11This ratio shows the ldquodip and riserdquoenergy dependence of the deficit which is characteristic ofoscillation and described by (1)
The bottom row of Figure 10 shows the spectra of atmo-spheric ]
120583and ]120583CC interactions as a function of 119871119864 where
119871 is the distance traveled by the neutrino and 119864 is its energyThe atmospheric neutrino events are divided into ]
120583and ]120583
interactions according to the direction of curvature of themuon and separated into samples depending on whether ornot the interaction vertex is contained in the detector
All the observed ]120583and ]120583CC interactions are fit accord-
ing to the two-flavour model of (1) under the assumptionthat neutrinos and antineutrinos have the same oscillationparametersThe resultingmeasurement of |Δ1198982| and sin2(2120579)is shown in Figure 12 The fit yields |Δ1198982| = (241
+009
minus010) times
10minus3 eV2 and sin2(2120579) = 0950
+0035
minus0036 disfavouring maximal
mixing at the 86 confidence level Figure 12 compares thismeasurement to those from Super-Kamiokande [61] andT2K [62] The MINOS measurement is the most precisedetermination of |Δ1198982| and all measurements of sin2(2120579) areconsistent
41 Muon Antineutrino Disappearance In the standardmodel of neutrino oscillation neutrinos and antineutrinosobey the same parameters with CPT symmetry requiringthat the masses of particles and antiparticles are identicalThe most sensitive test of this symmetry in other sectors isfrom the kaon system [63] The data from the antineutrino-enhanced beam and the interaction of atmospheric antineu-trinos enables the first direct comparison of the neutrinoand antineutrino oscillation parameters in the atmosphericregion This comparison provides a limit on nonstandardinteractions with the matter being passed through by theneutrino beam [64ndash70]
Figure 10 showed the energy spectra of ]120583interactions
observed in the FD These spectra can be fit in the two-flavour model of (1) allowing the antineutrino oscillationparameters to differ from those for neutrinos This fit yieldsthe antineutrino parametermeasurement shown in Figure 13|Δ1198982| = (250
+023
minus025) times 10
minus3 eV2 and sin2(2120579) = 097+003
minus008
This is in excellent agreement with the parameters measured
Advances in High Energy Physics 9
Neutrino energy (GeV) Neutrino energy (GeV) Neutrino energy (GeV)
0
20
40
60
80
0
5
10
10
15
1515
20
20
25
25
30
Muon energy (GeV)
0
200
400
600
800
0
100
200
300
400
500
6001071 times 1020 POT
Even
ts (G
eV)
Even
ts (G
eV)
Even
ts (G
eV)
Even
ts (G
eV)
120583 120583
120583120583
0 02 4 56 0 2 4 68 910 12 14 0 2 4 6 8 10 12 14
Neutrino beam Neutrino beam Neutrino beam Antineutrino beam
contained-vertex 120583
nonfiducial 120583contained-vertex 120583
contained-vertex 120583 336 times 1020 POT
(a)
0
20
40
60
0
10
20
30
0
10
20
30
0
5
10
15
20
25
MINOS dataBest fit oscillationsNo oscillations
NC backgroundCosmic-ray muons
120583 120583 120583 120583
0 1 2 3 4 0 1 2 3 4 0 1 2 3 4 0 1 2 3 4
Even
ts
Even
ts
Even
ts
Even
ts
Atmos contained-vertex 120583 Atmos nonfiducial 120583minus Atmos nonfiducial 120583+3788kton-years
Atmos contained-vertex 120583
log10( (km)E (GeV)) log10( (km)E120583 (GeV))L L log10( (km)E (GeV))L log10( (km)E120583 (GeV))L
(b)
Figure 10 The energy spectra of ]120583and ]
120583CC interactions observed at the FD compared to the expectation with and without oscillation
(a) shows beam-induced neutrinos (b) shows atmospheric neutrinos
with neutrinos alone (the red line in Figure 13) It should benoted that the first MINOS measurement of the antineutrinooscillation parameters released in 2010 [17] yielded a notabletension between the ] and ] oscillation parameters whichwere in agreement only at the 20 confidence levelThis ten-sion was shown to be a statistical fluctuation as the additionof further data brought the ] and ] parameters measurementsinto good agreement [19 20]
5 Electron Neutrino andAntineutrino Appearance
A search for ]119890and ]
119890appearance in the ]
120583and ]
120583beams
enables a measurement of the mixing angle 12057913 It is critical
to know the level of background to the ]119890sample in the
FD The energy spectrum of background events measured inthe ND is used to predict the spectrum expected in the FDHowever the background consists of three components NCinteractions CC ]
120583and ]
120583interactions and the intrinsic ]
119890
component in the beam The relative contribution betweenthe ND and FD is different for all of these components sincethey are affected differently by oscillation and the kinematicsof the production in the beam are different Therefore each
backgroundmust be individually measuredTheNuMI beamcan be configured to produce neutrino beams of varyingenergy by altering the current passing through the magnetichorns and changing the relative positions of the target andhorns Between these different beam configurations therelative contributions of the three background componentschange in a well-understood way as shown in Figure 15By comparing the ND data to the simulation in the threedifferent beam configurations shown in the figure the contri-butions of the three background components can be extracted[71]
Using the data-driven background extraction procedurea total of 1277 background events are expected at the FDin the neutrino-dominated beam and 175 events in theantineutrino-enhanced beam In the data 152 and 20 eventsare observed respectively Figure 16 shows the energy spectraof these events divided into bins of the library eventmatchingdiscriminant variable Although CC ]
119890and ]119890events cannot
be separated on an event-by-event basis the change inthe relative numbers of neutrino and antineutrino inter-actions between the neutrino-dominated and antineutrino-enhanced beams is well knownThis allows separate limits tobe placed on the rates of ]
120583rarr ]119890and ]120583rarr ]119890transitions
on a statistical basis
10 Advances in High Energy PhysicsRa
tio to
no
osci
llatio
ns
05
1
15
2
25
0 10 15 20 30 50
MINOS far detector data
5Reconstructed 120583 energy (GeV)
1071 times 1020 POT
Prediction Δm2 = 241 times 10minus3eV2
Low energy beam 120583-mode
Figure 11 The ratio of the observed ]120583energy spectrum to the
expectation in the case of no oscillation in the neutrino-dominatedbeam The black points show the data the blue line shows the bestfit to the data
075 080 085 090 095 10015
20
25
30
35
40
90 CL68 CL
90 CL
sin2(2120579)
|Δm
2|(10minus3eV
2)
MINOS 3788 kt-yr atmospheric
336 times 1020 POT 120583 modeSuper-K zenith anglelowast
Super-K LElowast
T2Klowastlowast
lowastNeutrino 2012lowastlowastPRD 85 031103(R) (2012)
1071 times 1020 POT 120583 mode
Figure 12 The allowed regions for the atmospheric oscillationparameters |Δ1198982| and sin2(2120579) assuming identical neutrino andantineutrino oscillation parametersTheMINOS result is comparedto measurements from Super-Kamiokande [61] and T2K [62]
The data are fit to extract a measurement of 12057913 The
resulting measurement is shown in Figure 17 The measuredvalue of 120579
13depends on the CP violating phase 120575 which
directly affects the ]119890and ]
119890appearance probabilities and
themass hierarchy which affects the appearance probabilitiesthrough the interactions of the neutrinos with the matter in
MINOS 120583 disappearance1071 times 1020 POT 120583 mode336 times 1020 POT mode3788kt-yr atmospheric
90 CL120583120583120583 + 120583
120583120583120583 + 120583
Best fit
sin2(2120579) or sin2(2120579)
(|Δm
2|
or Δ
m2|)
(10minus3eV
2)
075 080 085 090 095 100
20
25
30
35
120583
|Figure 13 The allowed region for antineutrino oscillation param-eters (blue line) compared to the region measured with neutrinosalone (red line) and the region measured using both neutrinos andantineutrinos under the assumption they have the same parameters(black line)
20
25
30
20 25 30
|Δm
2| (10
minus3eV
2)
|Δm2| (10minus3eV2)
68 CL|Δm2| = |Δm2|
MINOS 120583 disappearance1071 times 1020 POT 120583 mode336 times 1020 POT mode3788kt-yr atmospheric
90 CLBest fit
120583
Figure 14 A comparison of the measured limits on the masssplittings of neutrinos and antineutrinos
the Earthrsquos crust Assuming a normal mass hierarchy 120575 = 0and 120579
23lt 1205874 MINOS measures 2sin2(2120579
13)sin2(120579
23) =
0051+0038
minus0030 Assuming an inverted mass hierarchy 120575 = 0
and 12057923
lt 1205874 MINOS measures 2sin2(212057913)sin2(120579
23) =
0093+0054
minus0049 This measurement is consistent with the results
from reactor neutrino searches [72ndash74] and the T2K experi-ment [75]
This MINOS measurement is the first ever search for ]119890
appearance in a long-baseline ]120583beam and the first search
Advances in High Energy Physics 11
Reconstructed energy (GeV)0 6 8
Frac
tion
of ev
ents
0
01
02
03
04
Standard MC
MINOS
2 4
Near detector 2011
NC120583-CCe-CC
(a)
Horn-off MC
Reconstructed energy (GeV)0 6 8
Frac
tion
of ev
ents
0
01
02
03
04 MINOS
2 4
Near detector 2011
NC120583-CCe-CC
(b)
High energy MC
Reconstructed energy (GeV)0 6 8
Frac
tion
of ev
ents
0
01
02
03
04 MINOS
2 4
Near detector 2011
NC120583-CCe-CC
(c)
Figure 15 The contribution of the three components to the background in the ]119890appearance search as simulated in the ND (a) the regular
(low energy) beam data (b) with no current in the NuMI focusing horns (c) a high energy beam configuration
for ]119890and ]119890appearance with significant matter effects Both
of these effects provide some sensitivity to the neutrinomass hierarchy and CP violation when the MINOS data iscompared to the measurements made by reactor neutrinosearches [72ndash74] (we have calculated a limit of sin2(2120579
13) =
0098 plusmn 0013 from the reactor data at the time of analysis)The sensitivity of MINOS to the mass hierarchy and CPviolation is modest but this contributes to the first analysisof the type that will be used by all future long-baselineexperiments The resulting values of the likelihood by whichMINOS disfavours various values of these parameters areshown in Figure 18 [76]
6 Search for Sterile Neutrino Mixing UsingNeutral-Current Interactions
The energy spectrum of NC interactions in the FD should beunchanged by standard neutrino oscillationThe existence ofone or more sterile neutrino flavours ]
119904 could cause a deficit
in the observed NC interaction rate As with all the MINOSoscillation analyses the energy spectrum of NC interactionsobserved in the ND (which was shown in Figure 8) is usedto predict the spectrum expected at the FD [77] The FDexpectation is shown in Figure 19 with the dashed blue linetaking into account ]
119890appearance corresponding to 120579
13=
115∘ (at the limit set by CHOOZ [78] and a little above
the current accepted value [29 72ndash75] this analysis usesonly the first 707 times 10
20 protons on target of data andwas performed before the recent positive measurements ofa nonzero 120579
13) The data are also shown in the figure and
are in good agreement with the expectation confirming thestandard model of neutrino oscillation This agreement canbe quantified using a test statistic 119877
119877 =119873data minus 119861CC
119878NC (7)
where 119873data is the number of events observed 119861CC is thepredicted background of CC interactions and 119878NC is the
predicted number of NC interactions A value of 119877 = 101 plusmn
006(stat) plusmn 005(syst) is obtained (over the full energy range0ndash120GeV) which is in good agreement with the expectationof 119877 = 1 in the case of no mixing with sterile neutrinos
The data are analysed with a model that assumes a singlesterile neutrino flavour mixing through the addition of afourth neutrino mass state119898
4≫ 1198983 This introduces a mass
splitting Δ119898243
with magnitude O(1 eV2) such that no oscil-lation-induced change to the event rate is observed at theND and the oscillatory energy dependence of the induceddepletion at the FD is so rapid that an overall uniform deple-tion is observed once the energy resolution of the detectors isaccounted forThismodel introduces three additionalmixingangles 120579
14 12057924 and 120579
34 MINOS is insensitive to 120579
14but sets
limits of 12057924= (00
+5
minus00)∘ and 120579
34= (00
+25
minus00)∘ These limits are
evaluated assuming 12057913at the CHOOZ limit
The limit on the coupling of sterile to active neutrinos canbe quantified by defining 119891
119904 the fraction of disappearing ]
120583
which have oscillated into ]119904
119891119904=
119875]120583rarr ]119904
1 minus 119875]120583rarr ]120583
(8)
For the model used in which 1198984≫ 119898
3 119891119904is evaluated
at 14 GeV the energy of maximal ]120583disappearance To
determine the limit on 119891119904 a large number of test values
are chosen of the mixing angles 12057924 12057934 and 120579
23 from
Gaussian distributions according to the measured values and1120590 uncertainties given above (with 120579
23constrained from the
measurements with CC ]120583interactions) 119891
119904is calculated for
each case and the value of 119891119904that is larger than 90 of the
test cases represents the limit MINOS limits 119891119904lt 040 at the
90 confidence level
7 The Future MINOS+
The MINOS experiment has made some very importantcontributions to our understanding of neutrino oscillation
12 Advances in High Energy Physics
Reconstructed energy (GeV)
Reconstructed energy (GeV)
Even
ts
30
0
10
20
Even
ts
30
0
10
20
Even
ts
30
0
10
20
2 4 6 8
2 4 6 8
Reconstructed energy (GeV)2 4 6 8
06 lt 120572LEM lt 07
MINOS far detector data
07 lt 120572LEM lt 08
120572LEM gt 08
mode
mode
mode
e CC signal
e CC signalBackgroundData
(a)
Even
ts
Reconstructed energy (GeV)2 4 6 8
Reconstructed energy (GeV)2 4 6 8
Reconstructed energy (GeV)2 4 6 8
06 lt 120572LEM lt 07
MINOS far detector data
Merged for fit
07 lt 120572LEM lt 08
120572LEM gt 08
mode
mode
mode
8
6
4
2
0
Even
ts
8
6
4
2
0
Even
ts
8
6
4
2
0
e CC signal
e CC signalBackgroundData
5ndash8GeV bins
(b)
Figure 16 The CC ]119890(a) and ]
119890(b) candidate events selected in the FD compared to the expectation without any ]
119890appearance (red) and
with the best fit for 12057913(purple) The events are divided into bins of the library event matching discriminant variable
Advances in High Energy Physics 13
20
15
10
05
000 01 02 03 04
2sin2(212057913)sin212057923
Δm2 gt 0
sin
120575(120587)
(a)
20
15
10
05
000 01 02 03 04
2sin2(212057913)sin212057923
MINOS best fit 12057923 lt 1205874
MINOS best fit 12057923 gt 1205874
Δm2 lt 0
MINOS
106 times 1020 POT -mode33 times 1020 POT -mode
68 CL 12057923 lt 1205874
90 CL 12057923 lt 1205874
120575(120587)
(b)
Figure 17 The allowed regions for 2sin2(212057913)sin2(120579
23)
120575(120587)
Δm2 gt 0 12057923 gt 1205874
Δm2 gt 0 12057923 lt 1205874
Δm2 lt 0 12057923 gt 1205874Δm2 lt 0 12057923 lt 1205874
3
2
1
00 1 1505 2
MINOS
90 CL
68 CL
minus2Δ
(L)
ln
Figure 18 The values of likelihood 119871 by which various values oftheCP violating parameter 120575 the mass hierarchy and the octant of12057923are disfavouredThis analysis uses MINOS data and information
from reactor neutrino measurements of 12057913[72ndash74]
physics and has finished taking data with the low energybeam for which it was designed However the experimentwill continue taking data and producing new results for thenext few years as MINOS+ [79] The NuMI beam is being
20
2018161410 12
Far detector data
Even
ts (G
eV)
00 2 4 6 8
40
60
80
100
120
140
12057913 = 0∘
12057913 = 115∘ 120575 = 120587 Δm232 gt 0
120583 CC background|Δm2
32| = 232 times 10minus3eV2
Ereco (GeV)
sin2212057923 = 1
Figure 19 The black dots show the energy spectrum of NCinteractions observed in the far detector The red lines show theexpectation in the case of no sterile neutrinos and 120579
13= 0 the blue
dashed line shows the same expectation with 12057913= 115
∘
upgraded to a higher energy and intensity for the NO]Aexperiment the far detector of which will sit 14 mrad offaxisNO]A will receive a narrow-band beam peaking at around2GeV which is ideal for searching for ]
119890appearance since
the background seen in MINOS from NC interactions ofhigh energy neutrinos will be heavily reduced Figure 20shows that the MINOS FD will see an intense ]
120583beam
14 Advances in High Energy Physics
1000
500
00 5 10 15 20
E (GeV)
MINOS+NOAMINOS
Preliminary
Simulated beam54 kton 6 times 1020 POT
120583CC
even
ts (G
eV)
Figure 20 The ]120583energy spectrum that will be observed by the
MINOS+ FD compared to the spectra observed by MINOS andNO]A
peaking at around 7GeV In this configuration MINOS+ willobserve around 4000 CC ]
120583interactions in the FD each
year unprecedented statistics for a long-baseline oscillationexperimentThis will offer a unique high precision test of thethree-flavour oscillation paradigm
MINOS+ will be able to make a very sensitive searchfor the sterile neutrinos suggested by the LSND [80] andMiniBooNE [81 82] data and by some interpretations ofreactor neutrino data [83] This search will cover more thanthree orders of magnitude in the mass splitting between thesterile and active neutrinos The signal that MINOS+ willsearch for is illustrated in Figure 21 Figure 21(a) illustratesthe increase in statistical precision thatMINOS+will provideon the ratio of the observed CC ]
120583interaction rate to
that expected without oscillations Figure 21(b) shows howthis ratio is modified if a sterile neutrino exists and mixeswith the active neutrinos an additional deficit of muonneutrino interactions occurs in the higher energy region ofthe spectrum In the model assumed here which introducesa single sterile neutrino state three new mixing angles areintroduced 120579
14 12057924 and 120579
34 An additional mass splitting
Δ1198982
43is also introduced The position in energy of the
additional deficit is governed by the value of the new masssplittingThemagnitude of the additional deficit in the CC ]
120583
interaction rate is governed primarily by the size of 12057924 this is
in comparison to short-baseline searches for ]119890disappearance
from reactors which are governed by 12057914and searches for ]
119890
appearance in ]120583beamswhich are governed by a combination
of 12057914
and 12057924 A detailed explanation of the global effort to
search for sterile neutrinos can be found in [84]The sensitivity of the MINOS+ experiment when com-
bined with the Bugey reactor neutrino data [85] is shown in
MINOS+ simulation
MINOS 1071 times 1021 POT06 times 1021 POT12 times 1021 POT18 times 1021 POT
120583su
rviv
al p
roba
bilit
y
Neutrino energy (GeV)0 5 10 15
15
1
05
0
(a)
P(
120583rarr
120583)
No sterile neutrinosΔm2
43 = 2 times 10minus2eV2 sin2(212057924) = 02
0 5 10 15 20
1
0
18
06
04
02
Neutrino energy (GeV)
(b)
Figure 21 (a) The black points show the ratio of the observed ]120583
energy spectrum to the expectation in the case of no oscillation inthe neutrino-dominated beam of MINOS The blue region showsthe statistical precision expected from MINOS+ (b) The black lineshows the muon neutrino survival probability in the case of nosterile neutrinos the red line shows how the probability would bemodified by the addition of mixing with a sterile neutrino
Figure 22 MINOS+ has the potential to rule out much of theLSND allowed region MINOS+ will begin taking data in thelate summer of 2013 and will continue taking data for at leasttwo years (Figure 22 assumes two years of data taking with aneutrino-dominated beam)
8 Conclusion
The MINOS experiment was conceived at a time when neu-trino oscillation had only recently been confirmed as thesolution to the problem of neutrino flavour change It has
Advances in High Energy Physics 15
Δm
2
10minus210minus2
10minus1
10minus1
10minus310minus4 1
1
10
102
LSND 90 CLLSND 99 CLKarmen2 90 CLBugey 90 CLlowast
MiniBooNE 90 CLMiniBooNE 99 CLMINOS+ and Bugeycombination 90 CL
sin22120579120583e
lowastGLoBES 2012 fit with new reactor fluxescourtesy of P Huber
Figure 22 The sensitivity of MINOS+ to the existence of sterileneutrinos when combined with data from the Bugey [85] reactorneutrino experiment Δ1198982 is the splitting between the three knownneutrino mass states and a new fourth state 120579
120583119890is the mixing angle
governing ]120583rarr ]119890transitions when a fourth sterile neutrino state
is introduced into the PMNSmixingmatrixThis figure assumes twoyears of MINOS+ running with a neutrino-dominated beam
played a hugely influential role in bringing neutrino oscilla-tion physics into an era of precision measurement MINOSrsquosmeasurement of the largest neutrino mass splitting is themost precise in the world MINOS has made the first directprecision measurement of the corresponding antineutrinoparameters a measurement that promises to remain theworldrsquos most precise for many years And MINOS has playeda role in the discovery of a nonzero value for 120579
13
Now that the value of 12057913is known the neutrino physics
community can move on to determine the neutrino masshierarchy and to search for CP violation in the neutrinosector MINOS has pioneered a number of techniques thatwill be used by future experiments The two-detector setupall important in reducing the impact of systematic uncer-tainties is the design of choice for any new experiment andMINOS has demonstrated methods of using a near detectorto determine the expectation at a far detector MINOS hasperformed the first search for ]
119890appearance in a ]
120583beam
and the first search for ]119890and ]119890appearance with significant
matter effects demonstrating the analysis techniques that willbe used to determine the mass hierarchy and CP violationparameter
In the second half of 2013 MINOS will begin taking dataas the MINOS+ experiment which will make ever more pre-cise tests of the three-flavour neutrino oscillation paradigmand set world-leading limits on the existence of sterileneutrinos This is an exciting future for an experiment thatwith a decade of data taking so far has already created alasting legacy for itself in our understanding of the neutrino
A comparison of themeasured neutrino and antineutrinomass splittings is shown in Figure 14 the difference betweenthe two is constrained to |Δ119898
2| minus |Δ119898
2| = (012
+024
minus026) times
10minus3 eV2
Acknowledgment
The work of the MINOS and MINOS+ collaborations issupported by the US DoE the UK STFC the US NSF theState and University of Minnesota the University of Athensin Greece and Brazilrsquos FAPESP and CNPq The authors aregrateful to the Minnesota Department of Natural Resourcesthe crew of the Soudan Underground Laboratory and thepersonnel of Fermilab for their vital contributions
References
[1] S Wojcicki ldquoLong baseline neutrino oscillation programe inthe United Statesrdquo Nuclear Physics B vol 77 no 1ndash3 pp 182ndash186 1999 Proceedings of the 18th International Conference onNeutrino Physics and Astrophysics (Neutrino rsquo98) TakayamaJapan June 1998
[2] R Davis Jr D S Harmer and K C Hoffman ldquoSearch forneutrinos from the sunrdquo Physical Review Letters vol 20 no 21pp 1205ndash1209 1968
[3] A I Abazov O L Anosov E L Faizov et al ldquoSearch forneutrinos from sun using the reactionGa-71 (electron-neutrinoe-) Ge-71rdquo Physical Review Letters vol 67 pp 3332ndash3335 1991
[4] P Anselmann W Hampel G Heusser et al ldquoSolar neutrinosobserved by GALLEX at gran sassordquo Physics Letters B vol 285no 4 pp 376ndash389 1992
[5] M Aglietta G Battistoni E Bellotti et al ldquoExperimentalstudy of atmospheric neutrino flux in the NUSEX experimentrdquoEurophysics Letters vol 8 no 7 article 611 1989
[6] K S Hirata ldquoObservation of a small atmospheric V120583V119890ratio in
Kamiokanderdquo Physics Letters B vol 280 no 1-2 pp 146ndash1521992
[7] R Becker-Szendy C B Bratton D Casper et al ldquoElectron-and muon-neutrino content of the atmospheric fluxrdquo PhysicalReview D vol 46 pp 3720ndash3724 1992
[8] K Daum W Rhode P Bareyre et al ldquoDetermination ofthe atmospheric neutrino spectra with the frejus detectorrdquoZeitschrift fur Physik C vol 66 no 3 pp 417ndash428 1995
[9] S Ahlen M Ambrosio R Antolini and G Auriemma ldquoAtmo-spheric neutrino flux measurement using upgoing muonsrdquoPhysics Letters B vol 357 no 3 pp 481ndash486 1995
[10] WMAllison G J Alner D S Ayres et al ldquoMeasurement of theatmospheric neutrino flavour composition in Soudan 2rdquoPhysicsLetters B vol 391 no 3-4 pp 491ndash500 1997
16 Advances in High Energy Physics
[11] Y Fukuda T Hayakawa E Ichihara et al ldquoEvidence foroscillation of atmospheric neutrinosrdquo Physical Review Lettersvol 81 no 8 pp 1562ndash1567 1998
[12] Q R Ahmad R C Allen T C Andersen et al ldquoMeasurementof charged current interactions produced by solar neutrinos atthe sudbury neutrino observatoryrdquo Physical Review Letters vol87 Article ID 071301 2001
[13] Q R Ahmad R C Allen T C Andersen et al ldquoDirect evidencefor neutrino flavor transformation from neutral-current inter-actions in the sudbury neutrino observatoryrdquo Physical ReviewLetters vol 89 Article ID 011301 6 pages 2002
[14] B Pontecorvo ldquoInverse beta processes and nonconservation oflepton chargerdquo Journal of Experimental and Theoretical Physicsvol 34 pp 172ndash173 1958
[15] V N Gribov and B Pontecorvo ldquoNeutrino astronomy andlepton chargerdquo Physics Letters B vol 28 pp 493ndash496 1969
[16] Z Maki M Nakagawa and S Sakata ldquoRemarks on the unifiedmodel of elementary particlesrdquo Progress of Theoretical Physicsvol 28 no 5 pp 870ndash880 1962
[17] P Adamson C Andreopoulos D J Auty et al ldquoFirst directobservation of muon antineutrino disappearancerdquo PhysicalReview Letters vol 107 no 2 Article ID 021801 2011
[18] P Adamson D J Auty D S Ayres et al ldquoSearch for thedisappearance of muon antineutrinos in the NuMI neutrinobeamrdquo Physical Review D vol 84 no 7 Article ID 071103 6pages 2011
[19] P Adamson D S Ayres C Backhouse et al ldquoImprovedmeasurement of muon antineutrino disappearance inMINOSrdquoPhysical Review Letters vol 108 no 19 Article ID 191801 5pages 2012
[20] P Adamson I Anghel C Backhouse et al ldquoMeasurementof Neutrino and Antineutrino Oscillations Using Beam andAtmospheric Data in MINOSrdquo Physical Review Letters vol 110no 25 Article ID 251801 6 pages 2013
[21] K Anderson B Bernstein D Boehnlein et al ldquoThe NuMIFacility Technical Design Reportrdquo FERMILAB-DESIGN-1998-01 1998
[22] D G Michael P Adamson T Alexopoulos et al ldquoObservationof muon neutrino disappearance with the MINOS detectors inthe NuMI neutrino beamrdquo Physical Review Letters vol 97 no19 Article ID 191801 6 pages 2006
[23] P Adamson C Andreopoulos K E Arms et al ldquoStudy ofmuon neutrino disappearance using the fermilab main injectorneutrino beamrdquo Physical Review D vol 77 no 7 Article ID072002 34 pages 2008
[24] P Adamson C Andreopoulos K E Arms et al ldquoMeasurementof neutrino oscillations with theMINOS detectors in the NuMIbeamrdquo Physical Review Letters vol 101 no 13 Article ID 1318025 pages 2008
[25] P Adamson C Andreopoulos R Armstrong et al ldquoMea-surement of the neutrino mass splitting and flavor mixing byMINOSrdquo Physical Review Letters vol 106 no 18 Article ID181801 6 pages 2011
[26] P Adamson C Andreopoulos K E Arms et al ldquoSearch formuon-neutrino to electron-neutrino transitions in MINOSrdquoPhysical Review Letters vol 103 no 26 Article ID 261802 5pages 2009
[27] PAdamsonCAndreopoulosD J Auty et al ldquoNew constraintsonmuon-neutrino to electron-neutrino transitions inMINOSrdquoPhysical ReviewD vol 82 no 5 Article ID 051102 6 pages 2010
[28] P Adamson D J Auty D S Ayres et al ldquoImproved search formuon-neutrino to electron-neutrino oscillations in MINOSrdquoPhysical Review Letters vol 107 no 18 Article ID 181802 6pages 2011
[29] P Adamson I Anghel C Backhouse et al ldquoElectron neutrinoand antineutrino appearance in the full MINOS data samplerdquoPhysical Review Letters vol 110 no 17 Article ID 171801 6 pages2013
[30] P Adamson C Andreopoulos K E Arms et al ldquoSearch foractive neutrino disappearance using neutral-current interac-tions in theMINOS long-baseline experimentrdquo Physical ReviewLetters vol 101 no 22 Article ID 221804 5 pages 2008
[31] P Adamson C Andreopoulos D J Auty et al ldquoSearch for ster-ile neutrino mixing in the MINOS long-baseline experimentrdquoPhysical Review D vol 81 no 5 Article ID 052004 18 pages2010
[32] P Adamson D J Auty D S Ayres et al ldquoActive to sterileneutrino mixing limits from neutral-current interactions inMINOSrdquo Physical Review Letters vol 107 no 1 Article ID011802 5 pages 2011
[33] Z Pavlovic Observation of disappearance of muon neutrinos inthe NuMI beam [PhD thesis] University of Texas at AustinAustin Tex USA 2008
[34] F Ballarini G Battistoni M Campanella et al ldquoThe FLUKAcode an overviewrdquo Journal of Physics vol 41 article 151 2006
[35] S Agostinelli J Allison K Amako et al ldquoGEANT4mdasha sim-ulation toolkitrdquo Nuclear Instruments and Methods in PhysicsResearch A vol 506 no 3 pp 250ndash303 2003
[36] G Battistoni F Cerutti A Fasso et al ldquoThe FLUKA codedescription and benchmarkingrdquo in Proceedings of the HadronicShower Simulation Workshop vol 896 of AIP Conference Pro-ceedings pp 31ndash49 Batavia Ill USA September 2006
[37] D G Michaele P Adamson T Alexopoulos et al ldquoThe mag-netized steel and scintillator calorimeters of the MINOS exper-imentrdquoNuclear Instruments and Methods in Physics Research Avol 596 no 2 pp 190ndash228 2008
[38] I E Stockdale A Bodek F Borcherding N Giokaris et alldquoLimits on muon-neutrino oscillations in the mass range 30 lt9987791198982lt 1000 eV2c4 rdquo Physical Review Letters vol 52 no 16 pp
1384ndash1388 1984[39] F Dydak G J Feldman C Guyot et al ldquoA search for V
120583
oscillations in the9987791198982 range 03ndash90 eV2 rdquo Physics Letters B vol134 no 3-4 pp 281ndash286 1984
[40] F Bergsma J Dorenbosch M Jonker et al ldquoA searchfor oscillations of muon neutrinos in an experiment withLEcong07 kmGeVrdquo Physics Letters B vol 142 no 1-2 pp 103ndash1101984
[41] M H Ahn E Aliu S Andringa et al ldquoMeasurement ofneutrino oscillation by the K2K experimentrdquo Physical ReviewD vol 74 no 7 Article ID 072003 39 pages 2006
[42] P Adamson T Alexopoulos W W M Allison et al ldquoFirstobservations of separated atmospheric V
120583and ]
120583events in the
MINOS detectorrdquo Physical Review D vol 73 no 7 Article ID072002 2006
[43] P Adamson C Andreopoulos K E Arms et al ldquoCharge-separated atmospheric neutrino-inducedmuons in theMINOSfar detectorrdquo Physical ReviewD vol 75 no 9 Article ID 09200314 pages 2007
[44] P Adamson C Backhouse G Barr et al ldquoMeasurements ofatmospheric neutrinos and antineutrinos in the MINOS fardetectorrdquo Physical Review D vol 86 no 5 Article ID 05200720 pages 2012
Advances in High Energy Physics 17
[45] M A Kordosky Hadronic interactions in the MINOS detectors[PhD thesis] University of Texas at Austin Austin Tex USA2004
[46] P L Vahle Electromagnetic interactions in the MINOS detectors[PhD thesis] University of Texas at Austin Austin Tex USA2004
[47] C Backhouse Measuring neutrino oscillation parameters using]120583disappearance inMINOS [PhD thesis] University of Oxford
Oxford UK 2011[48] T M Cover and P E Hart ldquoNearest neighbor pattern classifi-
cationrdquo IEEE Transactions on Information Theory vol 13 no 1pp 21ndash27 1967
[49] R Ospanov A measurement of muon neutrino disappearancewith the MINOS detectors and NuMI beam [PhD thesis]University of Texas at Austin Austin Tex USA 2008
[50] J S Marshall A study of muon neutrino disappearance with theMINOS detectors and the NuMI neutrino beam [PhD thesis]University of Cambridge Cambridge UK 2008
[51] J P OchoaA search formuon neutrino to electron neutrino oscil-lations in the MINOS Experiment [PhD thesis] The CaliforniaInstitute of Technology Pasadena Calif USA 2009
[52] R TonerMeasuring 12057913via muon neutrino to electron neutrino
oscillations in the MINOS experiment [PhD thesis] Universityof Cambridge Cambridge UK 2011
[53] A Holin Electron neutrino appearance in the MINOS experi-ment [PhD thesis] University College London London UK2010
[54] J Boehm Measurement of electron neutrino appearance withthe MINOS experiment [PhD thesis] Harvard UniversityCambridge Mass USA 2009
[55] G Tinti Sterile neutrino oscillations in MINOS and hadronproduction in pC collisions [PhD thesis] University of OxfordOxford UK 2010
[56] J J EvansMeasuring antineutrino oscillations with the MINOSexperiment [PhD thesis] University of Oxford Oxford UK2008
[57] S J ColemanAmeasurement of neutrino oscillations withmuonneutrinos in the MINOS experiment [PhD thesis] College ofWilliam ampMary Williamsburg Va USA 2011
[58] J S Mitchell Measuring ]120583disappearance with the MINOS
experiment [PhD thesis] University of Cambridge CambridgeUK 2011
[59] A McGowan Observation of deficit in NuMI neutrino-inducedrock and non-fiducial muons in MINOS far detector andmeasurement of neutrino oscillation parameters [PhD thesis]University of Minnesota Minneapolis Minn USA 2007
[60] M StraitMeasurement of neutrino oscillation parameters usinganti-fiducial charged current events in MINOS [PhD thesis]University of Minnesota Minneapolis Minn USA 2010
[61] Y Itow ldquoAtmospheric neutrinosmdashresults from running exper-imentsrdquo in Proceedings of the 25th International Conference onNeutrino Physics and Astrophysics (Neutrino rsquo12) Kyoto JapanJune 2012
[62] K Abe N Abgrall Y Ajima et al ldquoFirst muon-neutrinodisappearance study with an off-axis beamrdquo Physical Review Dvol 85 no 3 Article ID 031103 8 pages 2012
[63] K Nakamura ldquoReview of particle physicsrdquo Journal of Physics Gvol 37 Article ID 075021 2010
[64] L Wolfenstein ldquoNeutrino oscillations in matterrdquo PhysicalReview D vol 17 no 9 pp 2369ndash2374 1978
[65] J W F Valle ldquoResonant oscillations of massless neutrinos inmatterrdquo Physics Letters B vol 199 no 3 pp 432ndash436 1987
[66] M C Gonzalez-Garcia M M Guzzo P I Krastev et alldquoAtmospheric neutrino observations and flavor changing inter-actionsrdquo Physical Review Letters vol 82 no 16 pp 3202ndash32051999
[67] A Friedland C Lunardini and M Maltoni ldquoAtmosphericneutrinos as probes of neutrino-matter interactionsrdquo PhysicalReview D vol 70 no 11 Article ID 111301 2004
[68] Z IsvanAntineutrino oscillations and a Search for non-standardInteractions with the MINOS [PhD thesis] University of Pitts-burgh Pittsburgh Pa USA 2012
[69] W A Mann D Cherdack W Musial and T Kafka ldquoApparentmultiple 998779119898
32
2 in ]120583and V
120583survival oscillations from nonstan-
dard interactionmatter effectrdquo Physical Review D vol 82 no 11Article ID 113010 8 pages 2010
[70] J Kopp P A N Machado and S J Parke ldquoInterpretation ofMINOS data in terms of nonstandard neutrino interactionsrdquoPhysical Review D vol 82 no 11 Article ID 113002 12 pages2010
[71] J A B Coelho Investigacao de mecanismos alternativos aoscilacao de neutrinos no experimentos MINOS [PhD thesis]Universidade Estadual de Campinas Sao Paulo Brazil 2012
[72] F P An Q An J Z Bai A B Balantekin et al ldquoImprovedmeasurement of electron antineutrino disappearance at DayaBayrdquo Chinese Physics C vol 37 Article ID 011001 21 pages 2013
[73] J K Ahn S Chebotaryov J H Choi et al ldquoObservationof reactor electron antineutrinos disappearance in the RENOexperimentrdquo Physical Review Letters vol 108 Article ID 1918026 pages 2012
[74] Y Abe C Aberle J C dos Anjos et al ldquoReactor electronantineutrino disappearance in the Double Chooz experimentrdquoPhysical Review D vol 86 Article ID 052008 2012
[75] K Abe N Abgrall H Aihara et al ldquoEvidence of electronneutrino appearance in a muon neutrino beamrdquo PhysicalReview D vol 88 no 3 Article ID 032002 41 pages 2013
[76] A Schreckenberger Electron neutrino and antineutrino appear-ance in the MINOS detector [PhD thesis] University of Min-nesota Minneapolis Minn USA 2013
[77] D J Koskinen MINOS sterile neutrino search [PhD thesis]University College London London UK 2009
[78] M Apollonio A Baldini C Bemporad et al ldquoSearch forneutrino oscillations on a long base-line at the CHOOZ nuclearpower stationrdquoTheEuropean Physical Journal C vol 27 pp 331ndash374 2003
[79] G Tzanankos M Bishai M Diwan et alMINOS+ a proposalto FNAL to run MINOS with the medium energy NuMI beam[PhD thesis] University of Athens Athens Greece 2011
[80] A Aguilar L B Auerbach R L Burman et al ldquoEvidence forneutrino oscillations from the observation of ]
119890e appearance
in a ]120583beamrdquo Physical Review D vol 64 Article ID 112007 22
pages 2001[81] A A Aguilar-Arevalo C E Anderson S J Brice et al ldquoSearch
for electron antineutrino appearance at the Δ119898 sim 1 eV2 ScalerdquoPhysical Review Letters vol 103 no 11 Article ID 111801 2009
[82] A A Aguilar-Arevalo C E Anderson A O Bazarko et alldquoImproved search for V
120583rarr V119890oscillations in the MiniBooNE
experimentrdquo Physical Review Letter vol 110 no 10 Article ID161801 2013
[83] GMentionM Fechner T Lasserre et al ldquoReactor antineutrinoanomalyrdquo Physical Review D vol 83 Article ID 073006 20pages 2011
18 Advances in High Energy Physics
[84] KNAbazajianMAAcero S KAgarwalla et al ldquoLight sterileneutrinos a white paperrdquo httparxivorgabs12045379
[85] B Achkar R Aleksan M Avenier et al ldquoSearch for neutrinooscillations at 15 40 and 95meters from a nuclear power reactorat Bugeyrdquo Nuclear Physics B vol 434 no 3 pp 503ndash532 1995
Submit your manuscripts athttpwwwhindawicom
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Superconductivity
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ThermodynamicsJournal of
Advances in High Energy Physics 7
sin2(212057913) = 01
Δm232 gt 0 120575cp = 0 12057923 =
120587
4
Background
MINOS far detector80
60
40
20
00 01 02 03 04 05 06 07 08 09 1
LEM discriminant
Signal times10
Even
ts8
2times10
20PO
T
(a)
LEM discriminant
Even
ts10
19PO
T
DataMonte Carlo
MINOS near detector8000
6000
4000
2000
00 01 02 03 04 05 06 07 08 09 1
(b)
Figure 7 (a) The library event matching discriminant showing the expected distribution for background and CC ]119890signal events in the far
detector in the neutrino-dominated beam Note that the signal simulated for sin2(212057913) = 01 120575 = 0 and a normal mass hierarchy has been
scaled up by a factor of ten for visibility (b)The same discriminant as observed in the near detector compared with the simulated expectation
Near detector dataMonte Carlo prediction
20
10
30
50
2018161410 120
0 2 4 6 8
40
60
120583 CC background
Ereco (GeV)
104
even
ts (G
eV)
Figure 8 The sample of events identified as NC interactions in thenear detector
cut-based approach is taken [55] events are classified asNC-like if the event contains no reconstructed track or ifthe track extends no more than six planes past the end ofthe shower The resulting distribution of NC interactions inthe near detector is shown in Figure 8 The NC identificationefficiency is 89 with 61 purity This selection will identify97 of ]
119890CC interactions as NC events therefore an analysis
of NC interactions in the FD must account for the ]119890
appearance caused by a nonzero 12057913
34 Selection of Atmospheric Neutrinos Atmospheric neu-trino interactions are selected out of any activity seen in
the FD outside of the 10 120583s periods when the NuMI beamis active [44] The oscillation signal is contained in the ]
120583
CC interactions and as with the beam-induced interactionsthese are identified by the presence of a muon track The FDbegan taking data with atmospheric neutrinos in July 2003two years before the NuMI beam began running
The FD has a single-hit timing resolution of 25 ns Thistiming information is used to determine the direction inwhich the detector activity is traveling Any downwardstraveling activity is required to begin well inside the detec-tor to eliminate cosmic muons entering from above Allupwards or horizontally traveling activity is almost certainto be neutrino-induced since no other particle can survivethrough the many kilometres of rock All activity with azenith angle of cos 120579
119911lt 014 is defined as horizontal or down-
going this corresponds to an overburden of at least 14 kmwater equivalent
From this sample of neutrino-induced activity all eventswith a track crossing at least eight planes are designatedtrack-like all events with only shower-like activity crossing atleast four planes are designated shower-like These track-likeand shower-like samples are used in the neutrino oscillationmeasurementsThe track-like sample contains the oscillationsignal of ]
120583disappearance The shower-like sample contains
mainly NC interactions and ]119890and ]
119890CC interactions it
shows little oscillation signal but is very important for settingthe normalization of the atmospheric neutrino flux
4 Muon Neutrino andAntineutrino Disappearance
The atmospheric oscillation parameters |Δ1198982| and sin2(2120579)aremeasured by observing and fitting the energy dependenceof ]120583and ]
120583disappearance To minimise the impact of
8 Advances in High Energy Physics
20
40
60
80
100
120
0 10 15 20 30 50
Even
tstimes10
4(G
eV)
MINOS near detector dataMCMC uncertaintyNC background
MINOS near detectorLow energy beam 120583-mode729 times 1020 POT
Reconstructed 120583 energy (GeV)5
Figure 9 The energy spectrum of ]120583CC interactions observed in
the ND compared to the simulation
systematic uncertainties the energy spectra of the ]120583and
]120583CC interactions observed in the ND (shown in Figure 9
for the neutrino-dominated beam) are used to predict thespectrum at the FD in the absence of oscillation [23 56]The neutrino energy spectra at the ND and FD are notidentical the ND subtends a relatively large angle to thebeam so for each pion or kaon a range of decay anglescan produce a neutrino that passes through the detectorcorresponding to a range of neutrino energies However theFD is effectively a point when viewed from the neutrinoproduction location so a single decay angle for each hadrontherefore a single neutrino energy contributes to the fluxTo take this difference into account the hadron-decay kine-matics are encoded into a beam transfer matrix that convertsthe observed ND flux into a predicted FD flux Once theND data has been used in this way the most importantsystematic uncertainties are those that can affect the twodetectors differently primarily reconstruction efficienciesand miscalibrations of the neutrino energy measurementin the detectors [57] These uncertainties are included inthe fit that extracts the oscillation parameters [58] Theuncertainty on the reconstruction efficiency is modeled as a16 uncertainty on the relative rate of events between theND and FD The uncertainty on the measurement of muonenergy has two components that are fully correlated betweenthe detectors a 2 uncertainty on energies measured fromrange and a 3 uncertainty on energies measured fromthe curvature in the magnetic field The uncertainty in thehadronic energy measurements also has two componentsAn uncertainty arising from shower modeling uncertaintiesand calibration is fully correlated between the detectorsand is parameterized as (66 + 35119890119864shw14GeV) The secondcomponent is uncorrelated between the detectors and is 19
in theND and 11 in the FD this is dominated by calibrationuncertainties
The top row of Figure 10 shows the predicted spectra of]120583and ]120583CC interactions from the neutrino-dominated and
antineutrino-enhanced beams at the FD along with the dataIn the neutrino-dominated beam an additional sample isused consisting of neutrinos interacting outside the fiducialvolume of the detector and in the rock surrounding thedetector [59 60] This nonfiducial sample consists mainlyof high energy neutrinos and has significantly lower res-olution as not all the energy is contained in the detectorhowever it does contain some oscillation information Intotal 8100 reconstructed neutrino events are used in theanalysis without oscillations 9471 would be expected Inall samples a clear energy-dependent deficit of ]
120583and
]120583interactions is observed The ratio of the data to the
expectation for the ]120583interactions in the neutrino-dominated
beam is shown in Figure 11This ratio shows the ldquodip and riserdquoenergy dependence of the deficit which is characteristic ofoscillation and described by (1)
The bottom row of Figure 10 shows the spectra of atmo-spheric ]
120583and ]120583CC interactions as a function of 119871119864 where
119871 is the distance traveled by the neutrino and 119864 is its energyThe atmospheric neutrino events are divided into ]
120583and ]120583
interactions according to the direction of curvature of themuon and separated into samples depending on whether ornot the interaction vertex is contained in the detector
All the observed ]120583and ]120583CC interactions are fit accord-
ing to the two-flavour model of (1) under the assumptionthat neutrinos and antineutrinos have the same oscillationparametersThe resultingmeasurement of |Δ1198982| and sin2(2120579)is shown in Figure 12 The fit yields |Δ1198982| = (241
+009
minus010) times
10minus3 eV2 and sin2(2120579) = 0950
+0035
minus0036 disfavouring maximal
mixing at the 86 confidence level Figure 12 compares thismeasurement to those from Super-Kamiokande [61] andT2K [62] The MINOS measurement is the most precisedetermination of |Δ1198982| and all measurements of sin2(2120579) areconsistent
41 Muon Antineutrino Disappearance In the standardmodel of neutrino oscillation neutrinos and antineutrinosobey the same parameters with CPT symmetry requiringthat the masses of particles and antiparticles are identicalThe most sensitive test of this symmetry in other sectors isfrom the kaon system [63] The data from the antineutrino-enhanced beam and the interaction of atmospheric antineu-trinos enables the first direct comparison of the neutrinoand antineutrino oscillation parameters in the atmosphericregion This comparison provides a limit on nonstandardinteractions with the matter being passed through by theneutrino beam [64ndash70]
Figure 10 showed the energy spectra of ]120583interactions
observed in the FD These spectra can be fit in the two-flavour model of (1) allowing the antineutrino oscillationparameters to differ from those for neutrinos This fit yieldsthe antineutrino parametermeasurement shown in Figure 13|Δ1198982| = (250
+023
minus025) times 10
minus3 eV2 and sin2(2120579) = 097+003
minus008
This is in excellent agreement with the parameters measured
Advances in High Energy Physics 9
Neutrino energy (GeV) Neutrino energy (GeV) Neutrino energy (GeV)
0
20
40
60
80
0
5
10
10
15
1515
20
20
25
25
30
Muon energy (GeV)
0
200
400
600
800
0
100
200
300
400
500
6001071 times 1020 POT
Even
ts (G
eV)
Even
ts (G
eV)
Even
ts (G
eV)
Even
ts (G
eV)
120583 120583
120583120583
0 02 4 56 0 2 4 68 910 12 14 0 2 4 6 8 10 12 14
Neutrino beam Neutrino beam Neutrino beam Antineutrino beam
contained-vertex 120583
nonfiducial 120583contained-vertex 120583
contained-vertex 120583 336 times 1020 POT
(a)
0
20
40
60
0
10
20
30
0
10
20
30
0
5
10
15
20
25
MINOS dataBest fit oscillationsNo oscillations
NC backgroundCosmic-ray muons
120583 120583 120583 120583
0 1 2 3 4 0 1 2 3 4 0 1 2 3 4 0 1 2 3 4
Even
ts
Even
ts
Even
ts
Even
ts
Atmos contained-vertex 120583 Atmos nonfiducial 120583minus Atmos nonfiducial 120583+3788kton-years
Atmos contained-vertex 120583
log10( (km)E (GeV)) log10( (km)E120583 (GeV))L L log10( (km)E (GeV))L log10( (km)E120583 (GeV))L
(b)
Figure 10 The energy spectra of ]120583and ]
120583CC interactions observed at the FD compared to the expectation with and without oscillation
(a) shows beam-induced neutrinos (b) shows atmospheric neutrinos
with neutrinos alone (the red line in Figure 13) It should benoted that the first MINOS measurement of the antineutrinooscillation parameters released in 2010 [17] yielded a notabletension between the ] and ] oscillation parameters whichwere in agreement only at the 20 confidence levelThis ten-sion was shown to be a statistical fluctuation as the additionof further data brought the ] and ] parameters measurementsinto good agreement [19 20]
5 Electron Neutrino andAntineutrino Appearance
A search for ]119890and ]
119890appearance in the ]
120583and ]
120583beams
enables a measurement of the mixing angle 12057913 It is critical
to know the level of background to the ]119890sample in the
FD The energy spectrum of background events measured inthe ND is used to predict the spectrum expected in the FDHowever the background consists of three components NCinteractions CC ]
120583and ]
120583interactions and the intrinsic ]
119890
component in the beam The relative contribution betweenthe ND and FD is different for all of these components sincethey are affected differently by oscillation and the kinematicsof the production in the beam are different Therefore each
backgroundmust be individually measuredTheNuMI beamcan be configured to produce neutrino beams of varyingenergy by altering the current passing through the magnetichorns and changing the relative positions of the target andhorns Between these different beam configurations therelative contributions of the three background componentschange in a well-understood way as shown in Figure 15By comparing the ND data to the simulation in the threedifferent beam configurations shown in the figure the contri-butions of the three background components can be extracted[71]
Using the data-driven background extraction procedurea total of 1277 background events are expected at the FDin the neutrino-dominated beam and 175 events in theantineutrino-enhanced beam In the data 152 and 20 eventsare observed respectively Figure 16 shows the energy spectraof these events divided into bins of the library eventmatchingdiscriminant variable Although CC ]
119890and ]119890events cannot
be separated on an event-by-event basis the change inthe relative numbers of neutrino and antineutrino inter-actions between the neutrino-dominated and antineutrino-enhanced beams is well knownThis allows separate limits tobe placed on the rates of ]
120583rarr ]119890and ]120583rarr ]119890transitions
on a statistical basis
10 Advances in High Energy PhysicsRa
tio to
no
osci
llatio
ns
05
1
15
2
25
0 10 15 20 30 50
MINOS far detector data
5Reconstructed 120583 energy (GeV)
1071 times 1020 POT
Prediction Δm2 = 241 times 10minus3eV2
Low energy beam 120583-mode
Figure 11 The ratio of the observed ]120583energy spectrum to the
expectation in the case of no oscillation in the neutrino-dominatedbeam The black points show the data the blue line shows the bestfit to the data
075 080 085 090 095 10015
20
25
30
35
40
90 CL68 CL
90 CL
sin2(2120579)
|Δm
2|(10minus3eV
2)
MINOS 3788 kt-yr atmospheric
336 times 1020 POT 120583 modeSuper-K zenith anglelowast
Super-K LElowast
T2Klowastlowast
lowastNeutrino 2012lowastlowastPRD 85 031103(R) (2012)
1071 times 1020 POT 120583 mode
Figure 12 The allowed regions for the atmospheric oscillationparameters |Δ1198982| and sin2(2120579) assuming identical neutrino andantineutrino oscillation parametersTheMINOS result is comparedto measurements from Super-Kamiokande [61] and T2K [62]
The data are fit to extract a measurement of 12057913 The
resulting measurement is shown in Figure 17 The measuredvalue of 120579
13depends on the CP violating phase 120575 which
directly affects the ]119890and ]
119890appearance probabilities and
themass hierarchy which affects the appearance probabilitiesthrough the interactions of the neutrinos with the matter in
MINOS 120583 disappearance1071 times 1020 POT 120583 mode336 times 1020 POT mode3788kt-yr atmospheric
90 CL120583120583120583 + 120583
120583120583120583 + 120583
Best fit
sin2(2120579) or sin2(2120579)
(|Δm
2|
or Δ
m2|)
(10minus3eV
2)
075 080 085 090 095 100
20
25
30
35
120583
|Figure 13 The allowed region for antineutrino oscillation param-eters (blue line) compared to the region measured with neutrinosalone (red line) and the region measured using both neutrinos andantineutrinos under the assumption they have the same parameters(black line)
20
25
30
20 25 30
|Δm
2| (10
minus3eV
2)
|Δm2| (10minus3eV2)
68 CL|Δm2| = |Δm2|
MINOS 120583 disappearance1071 times 1020 POT 120583 mode336 times 1020 POT mode3788kt-yr atmospheric
90 CLBest fit
120583
Figure 14 A comparison of the measured limits on the masssplittings of neutrinos and antineutrinos
the Earthrsquos crust Assuming a normal mass hierarchy 120575 = 0and 120579
23lt 1205874 MINOS measures 2sin2(2120579
13)sin2(120579
23) =
0051+0038
minus0030 Assuming an inverted mass hierarchy 120575 = 0
and 12057923
lt 1205874 MINOS measures 2sin2(212057913)sin2(120579
23) =
0093+0054
minus0049 This measurement is consistent with the results
from reactor neutrino searches [72ndash74] and the T2K experi-ment [75]
This MINOS measurement is the first ever search for ]119890
appearance in a long-baseline ]120583beam and the first search
Advances in High Energy Physics 11
Reconstructed energy (GeV)0 6 8
Frac
tion
of ev
ents
0
01
02
03
04
Standard MC
MINOS
2 4
Near detector 2011
NC120583-CCe-CC
(a)
Horn-off MC
Reconstructed energy (GeV)0 6 8
Frac
tion
of ev
ents
0
01
02
03
04 MINOS
2 4
Near detector 2011
NC120583-CCe-CC
(b)
High energy MC
Reconstructed energy (GeV)0 6 8
Frac
tion
of ev
ents
0
01
02
03
04 MINOS
2 4
Near detector 2011
NC120583-CCe-CC
(c)
Figure 15 The contribution of the three components to the background in the ]119890appearance search as simulated in the ND (a) the regular
(low energy) beam data (b) with no current in the NuMI focusing horns (c) a high energy beam configuration
for ]119890and ]119890appearance with significant matter effects Both
of these effects provide some sensitivity to the neutrinomass hierarchy and CP violation when the MINOS data iscompared to the measurements made by reactor neutrinosearches [72ndash74] (we have calculated a limit of sin2(2120579
13) =
0098 plusmn 0013 from the reactor data at the time of analysis)The sensitivity of MINOS to the mass hierarchy and CPviolation is modest but this contributes to the first analysisof the type that will be used by all future long-baselineexperiments The resulting values of the likelihood by whichMINOS disfavours various values of these parameters areshown in Figure 18 [76]
6 Search for Sterile Neutrino Mixing UsingNeutral-Current Interactions
The energy spectrum of NC interactions in the FD should beunchanged by standard neutrino oscillationThe existence ofone or more sterile neutrino flavours ]
119904 could cause a deficit
in the observed NC interaction rate As with all the MINOSoscillation analyses the energy spectrum of NC interactionsobserved in the ND (which was shown in Figure 8) is usedto predict the spectrum expected at the FD [77] The FDexpectation is shown in Figure 19 with the dashed blue linetaking into account ]
119890appearance corresponding to 120579
13=
115∘ (at the limit set by CHOOZ [78] and a little above
the current accepted value [29 72ndash75] this analysis usesonly the first 707 times 10
20 protons on target of data andwas performed before the recent positive measurements ofa nonzero 120579
13) The data are also shown in the figure and
are in good agreement with the expectation confirming thestandard model of neutrino oscillation This agreement canbe quantified using a test statistic 119877
119877 =119873data minus 119861CC
119878NC (7)
where 119873data is the number of events observed 119861CC is thepredicted background of CC interactions and 119878NC is the
predicted number of NC interactions A value of 119877 = 101 plusmn
006(stat) plusmn 005(syst) is obtained (over the full energy range0ndash120GeV) which is in good agreement with the expectationof 119877 = 1 in the case of no mixing with sterile neutrinos
The data are analysed with a model that assumes a singlesterile neutrino flavour mixing through the addition of afourth neutrino mass state119898
4≫ 1198983 This introduces a mass
splitting Δ119898243
with magnitude O(1 eV2) such that no oscil-lation-induced change to the event rate is observed at theND and the oscillatory energy dependence of the induceddepletion at the FD is so rapid that an overall uniform deple-tion is observed once the energy resolution of the detectors isaccounted forThismodel introduces three additionalmixingangles 120579
14 12057924 and 120579
34 MINOS is insensitive to 120579
14but sets
limits of 12057924= (00
+5
minus00)∘ and 120579
34= (00
+25
minus00)∘ These limits are
evaluated assuming 12057913at the CHOOZ limit
The limit on the coupling of sterile to active neutrinos canbe quantified by defining 119891
119904 the fraction of disappearing ]
120583
which have oscillated into ]119904
119891119904=
119875]120583rarr ]119904
1 minus 119875]120583rarr ]120583
(8)
For the model used in which 1198984≫ 119898
3 119891119904is evaluated
at 14 GeV the energy of maximal ]120583disappearance To
determine the limit on 119891119904 a large number of test values
are chosen of the mixing angles 12057924 12057934 and 120579
23 from
Gaussian distributions according to the measured values and1120590 uncertainties given above (with 120579
23constrained from the
measurements with CC ]120583interactions) 119891
119904is calculated for
each case and the value of 119891119904that is larger than 90 of the
test cases represents the limit MINOS limits 119891119904lt 040 at the
90 confidence level
7 The Future MINOS+
The MINOS experiment has made some very importantcontributions to our understanding of neutrino oscillation
12 Advances in High Energy Physics
Reconstructed energy (GeV)
Reconstructed energy (GeV)
Even
ts
30
0
10
20
Even
ts
30
0
10
20
Even
ts
30
0
10
20
2 4 6 8
2 4 6 8
Reconstructed energy (GeV)2 4 6 8
06 lt 120572LEM lt 07
MINOS far detector data
07 lt 120572LEM lt 08
120572LEM gt 08
mode
mode
mode
e CC signal
e CC signalBackgroundData
(a)
Even
ts
Reconstructed energy (GeV)2 4 6 8
Reconstructed energy (GeV)2 4 6 8
Reconstructed energy (GeV)2 4 6 8
06 lt 120572LEM lt 07
MINOS far detector data
Merged for fit
07 lt 120572LEM lt 08
120572LEM gt 08
mode
mode
mode
8
6
4
2
0
Even
ts
8
6
4
2
0
Even
ts
8
6
4
2
0
e CC signal
e CC signalBackgroundData
5ndash8GeV bins
(b)
Figure 16 The CC ]119890(a) and ]
119890(b) candidate events selected in the FD compared to the expectation without any ]
119890appearance (red) and
with the best fit for 12057913(purple) The events are divided into bins of the library event matching discriminant variable
Advances in High Energy Physics 13
20
15
10
05
000 01 02 03 04
2sin2(212057913)sin212057923
Δm2 gt 0
sin
120575(120587)
(a)
20
15
10
05
000 01 02 03 04
2sin2(212057913)sin212057923
MINOS best fit 12057923 lt 1205874
MINOS best fit 12057923 gt 1205874
Δm2 lt 0
MINOS
106 times 1020 POT -mode33 times 1020 POT -mode
68 CL 12057923 lt 1205874
90 CL 12057923 lt 1205874
120575(120587)
(b)
Figure 17 The allowed regions for 2sin2(212057913)sin2(120579
23)
120575(120587)
Δm2 gt 0 12057923 gt 1205874
Δm2 gt 0 12057923 lt 1205874
Δm2 lt 0 12057923 gt 1205874Δm2 lt 0 12057923 lt 1205874
3
2
1
00 1 1505 2
MINOS
90 CL
68 CL
minus2Δ
(L)
ln
Figure 18 The values of likelihood 119871 by which various values oftheCP violating parameter 120575 the mass hierarchy and the octant of12057923are disfavouredThis analysis uses MINOS data and information
from reactor neutrino measurements of 12057913[72ndash74]
physics and has finished taking data with the low energybeam for which it was designed However the experimentwill continue taking data and producing new results for thenext few years as MINOS+ [79] The NuMI beam is being
20
2018161410 12
Far detector data
Even
ts (G
eV)
00 2 4 6 8
40
60
80
100
120
140
12057913 = 0∘
12057913 = 115∘ 120575 = 120587 Δm232 gt 0
120583 CC background|Δm2
32| = 232 times 10minus3eV2
Ereco (GeV)
sin2212057923 = 1
Figure 19 The black dots show the energy spectrum of NCinteractions observed in the far detector The red lines show theexpectation in the case of no sterile neutrinos and 120579
13= 0 the blue
dashed line shows the same expectation with 12057913= 115
∘
upgraded to a higher energy and intensity for the NO]Aexperiment the far detector of which will sit 14 mrad offaxisNO]A will receive a narrow-band beam peaking at around2GeV which is ideal for searching for ]
119890appearance since
the background seen in MINOS from NC interactions ofhigh energy neutrinos will be heavily reduced Figure 20shows that the MINOS FD will see an intense ]
120583beam
14 Advances in High Energy Physics
1000
500
00 5 10 15 20
E (GeV)
MINOS+NOAMINOS
Preliminary
Simulated beam54 kton 6 times 1020 POT
120583CC
even
ts (G
eV)
Figure 20 The ]120583energy spectrum that will be observed by the
MINOS+ FD compared to the spectra observed by MINOS andNO]A
peaking at around 7GeV In this configuration MINOS+ willobserve around 4000 CC ]
120583interactions in the FD each
year unprecedented statistics for a long-baseline oscillationexperimentThis will offer a unique high precision test of thethree-flavour oscillation paradigm
MINOS+ will be able to make a very sensitive searchfor the sterile neutrinos suggested by the LSND [80] andMiniBooNE [81 82] data and by some interpretations ofreactor neutrino data [83] This search will cover more thanthree orders of magnitude in the mass splitting between thesterile and active neutrinos The signal that MINOS+ willsearch for is illustrated in Figure 21 Figure 21(a) illustratesthe increase in statistical precision thatMINOS+will provideon the ratio of the observed CC ]
120583interaction rate to
that expected without oscillations Figure 21(b) shows howthis ratio is modified if a sterile neutrino exists and mixeswith the active neutrinos an additional deficit of muonneutrino interactions occurs in the higher energy region ofthe spectrum In the model assumed here which introducesa single sterile neutrino state three new mixing angles areintroduced 120579
14 12057924 and 120579
34 An additional mass splitting
Δ1198982
43is also introduced The position in energy of the
additional deficit is governed by the value of the new masssplittingThemagnitude of the additional deficit in the CC ]
120583
interaction rate is governed primarily by the size of 12057924 this is
in comparison to short-baseline searches for ]119890disappearance
from reactors which are governed by 12057914and searches for ]
119890
appearance in ]120583beamswhich are governed by a combination
of 12057914
and 12057924 A detailed explanation of the global effort to
search for sterile neutrinos can be found in [84]The sensitivity of the MINOS+ experiment when com-
bined with the Bugey reactor neutrino data [85] is shown in
MINOS+ simulation
MINOS 1071 times 1021 POT06 times 1021 POT12 times 1021 POT18 times 1021 POT
120583su
rviv
al p
roba
bilit
y
Neutrino energy (GeV)0 5 10 15
15
1
05
0
(a)
P(
120583rarr
120583)
No sterile neutrinosΔm2
43 = 2 times 10minus2eV2 sin2(212057924) = 02
0 5 10 15 20
1
0
18
06
04
02
Neutrino energy (GeV)
(b)
Figure 21 (a) The black points show the ratio of the observed ]120583
energy spectrum to the expectation in the case of no oscillation inthe neutrino-dominated beam of MINOS The blue region showsthe statistical precision expected from MINOS+ (b) The black lineshows the muon neutrino survival probability in the case of nosterile neutrinos the red line shows how the probability would bemodified by the addition of mixing with a sterile neutrino
Figure 22 MINOS+ has the potential to rule out much of theLSND allowed region MINOS+ will begin taking data in thelate summer of 2013 and will continue taking data for at leasttwo years (Figure 22 assumes two years of data taking with aneutrino-dominated beam)
8 Conclusion
The MINOS experiment was conceived at a time when neu-trino oscillation had only recently been confirmed as thesolution to the problem of neutrino flavour change It has
Advances in High Energy Physics 15
Δm
2
10minus210minus2
10minus1
10minus1
10minus310minus4 1
1
10
102
LSND 90 CLLSND 99 CLKarmen2 90 CLBugey 90 CLlowast
MiniBooNE 90 CLMiniBooNE 99 CLMINOS+ and Bugeycombination 90 CL
sin22120579120583e
lowastGLoBES 2012 fit with new reactor fluxescourtesy of P Huber
Figure 22 The sensitivity of MINOS+ to the existence of sterileneutrinos when combined with data from the Bugey [85] reactorneutrino experiment Δ1198982 is the splitting between the three knownneutrino mass states and a new fourth state 120579
120583119890is the mixing angle
governing ]120583rarr ]119890transitions when a fourth sterile neutrino state
is introduced into the PMNSmixingmatrixThis figure assumes twoyears of MINOS+ running with a neutrino-dominated beam
played a hugely influential role in bringing neutrino oscilla-tion physics into an era of precision measurement MINOSrsquosmeasurement of the largest neutrino mass splitting is themost precise in the world MINOS has made the first directprecision measurement of the corresponding antineutrinoparameters a measurement that promises to remain theworldrsquos most precise for many years And MINOS has playeda role in the discovery of a nonzero value for 120579
13
Now that the value of 12057913is known the neutrino physics
community can move on to determine the neutrino masshierarchy and to search for CP violation in the neutrinosector MINOS has pioneered a number of techniques thatwill be used by future experiments The two-detector setupall important in reducing the impact of systematic uncer-tainties is the design of choice for any new experiment andMINOS has demonstrated methods of using a near detectorto determine the expectation at a far detector MINOS hasperformed the first search for ]
119890appearance in a ]
120583beam
and the first search for ]119890and ]119890appearance with significant
matter effects demonstrating the analysis techniques that willbe used to determine the mass hierarchy and CP violationparameter
In the second half of 2013 MINOS will begin taking dataas the MINOS+ experiment which will make ever more pre-cise tests of the three-flavour neutrino oscillation paradigmand set world-leading limits on the existence of sterileneutrinos This is an exciting future for an experiment thatwith a decade of data taking so far has already created alasting legacy for itself in our understanding of the neutrino
A comparison of themeasured neutrino and antineutrinomass splittings is shown in Figure 14 the difference betweenthe two is constrained to |Δ119898
2| minus |Δ119898
2| = (012
+024
minus026) times
10minus3 eV2
Acknowledgment
The work of the MINOS and MINOS+ collaborations issupported by the US DoE the UK STFC the US NSF theState and University of Minnesota the University of Athensin Greece and Brazilrsquos FAPESP and CNPq The authors aregrateful to the Minnesota Department of Natural Resourcesthe crew of the Soudan Underground Laboratory and thepersonnel of Fermilab for their vital contributions
References
[1] S Wojcicki ldquoLong baseline neutrino oscillation programe inthe United Statesrdquo Nuclear Physics B vol 77 no 1ndash3 pp 182ndash186 1999 Proceedings of the 18th International Conference onNeutrino Physics and Astrophysics (Neutrino rsquo98) TakayamaJapan June 1998
[2] R Davis Jr D S Harmer and K C Hoffman ldquoSearch forneutrinos from the sunrdquo Physical Review Letters vol 20 no 21pp 1205ndash1209 1968
[3] A I Abazov O L Anosov E L Faizov et al ldquoSearch forneutrinos from sun using the reactionGa-71 (electron-neutrinoe-) Ge-71rdquo Physical Review Letters vol 67 pp 3332ndash3335 1991
[4] P Anselmann W Hampel G Heusser et al ldquoSolar neutrinosobserved by GALLEX at gran sassordquo Physics Letters B vol 285no 4 pp 376ndash389 1992
[5] M Aglietta G Battistoni E Bellotti et al ldquoExperimentalstudy of atmospheric neutrino flux in the NUSEX experimentrdquoEurophysics Letters vol 8 no 7 article 611 1989
[6] K S Hirata ldquoObservation of a small atmospheric V120583V119890ratio in
Kamiokanderdquo Physics Letters B vol 280 no 1-2 pp 146ndash1521992
[7] R Becker-Szendy C B Bratton D Casper et al ldquoElectron-and muon-neutrino content of the atmospheric fluxrdquo PhysicalReview D vol 46 pp 3720ndash3724 1992
[8] K Daum W Rhode P Bareyre et al ldquoDetermination ofthe atmospheric neutrino spectra with the frejus detectorrdquoZeitschrift fur Physik C vol 66 no 3 pp 417ndash428 1995
[9] S Ahlen M Ambrosio R Antolini and G Auriemma ldquoAtmo-spheric neutrino flux measurement using upgoing muonsrdquoPhysics Letters B vol 357 no 3 pp 481ndash486 1995
[10] WMAllison G J Alner D S Ayres et al ldquoMeasurement of theatmospheric neutrino flavour composition in Soudan 2rdquoPhysicsLetters B vol 391 no 3-4 pp 491ndash500 1997
16 Advances in High Energy Physics
[11] Y Fukuda T Hayakawa E Ichihara et al ldquoEvidence foroscillation of atmospheric neutrinosrdquo Physical Review Lettersvol 81 no 8 pp 1562ndash1567 1998
[12] Q R Ahmad R C Allen T C Andersen et al ldquoMeasurementof charged current interactions produced by solar neutrinos atthe sudbury neutrino observatoryrdquo Physical Review Letters vol87 Article ID 071301 2001
[13] Q R Ahmad R C Allen T C Andersen et al ldquoDirect evidencefor neutrino flavor transformation from neutral-current inter-actions in the sudbury neutrino observatoryrdquo Physical ReviewLetters vol 89 Article ID 011301 6 pages 2002
[14] B Pontecorvo ldquoInverse beta processes and nonconservation oflepton chargerdquo Journal of Experimental and Theoretical Physicsvol 34 pp 172ndash173 1958
[15] V N Gribov and B Pontecorvo ldquoNeutrino astronomy andlepton chargerdquo Physics Letters B vol 28 pp 493ndash496 1969
[16] Z Maki M Nakagawa and S Sakata ldquoRemarks on the unifiedmodel of elementary particlesrdquo Progress of Theoretical Physicsvol 28 no 5 pp 870ndash880 1962
[17] P Adamson C Andreopoulos D J Auty et al ldquoFirst directobservation of muon antineutrino disappearancerdquo PhysicalReview Letters vol 107 no 2 Article ID 021801 2011
[18] P Adamson D J Auty D S Ayres et al ldquoSearch for thedisappearance of muon antineutrinos in the NuMI neutrinobeamrdquo Physical Review D vol 84 no 7 Article ID 071103 6pages 2011
[19] P Adamson D S Ayres C Backhouse et al ldquoImprovedmeasurement of muon antineutrino disappearance inMINOSrdquoPhysical Review Letters vol 108 no 19 Article ID 191801 5pages 2012
[20] P Adamson I Anghel C Backhouse et al ldquoMeasurementof Neutrino and Antineutrino Oscillations Using Beam andAtmospheric Data in MINOSrdquo Physical Review Letters vol 110no 25 Article ID 251801 6 pages 2013
[21] K Anderson B Bernstein D Boehnlein et al ldquoThe NuMIFacility Technical Design Reportrdquo FERMILAB-DESIGN-1998-01 1998
[22] D G Michael P Adamson T Alexopoulos et al ldquoObservationof muon neutrino disappearance with the MINOS detectors inthe NuMI neutrino beamrdquo Physical Review Letters vol 97 no19 Article ID 191801 6 pages 2006
[23] P Adamson C Andreopoulos K E Arms et al ldquoStudy ofmuon neutrino disappearance using the fermilab main injectorneutrino beamrdquo Physical Review D vol 77 no 7 Article ID072002 34 pages 2008
[24] P Adamson C Andreopoulos K E Arms et al ldquoMeasurementof neutrino oscillations with theMINOS detectors in the NuMIbeamrdquo Physical Review Letters vol 101 no 13 Article ID 1318025 pages 2008
[25] P Adamson C Andreopoulos R Armstrong et al ldquoMea-surement of the neutrino mass splitting and flavor mixing byMINOSrdquo Physical Review Letters vol 106 no 18 Article ID181801 6 pages 2011
[26] P Adamson C Andreopoulos K E Arms et al ldquoSearch formuon-neutrino to electron-neutrino transitions in MINOSrdquoPhysical Review Letters vol 103 no 26 Article ID 261802 5pages 2009
[27] PAdamsonCAndreopoulosD J Auty et al ldquoNew constraintsonmuon-neutrino to electron-neutrino transitions inMINOSrdquoPhysical ReviewD vol 82 no 5 Article ID 051102 6 pages 2010
[28] P Adamson D J Auty D S Ayres et al ldquoImproved search formuon-neutrino to electron-neutrino oscillations in MINOSrdquoPhysical Review Letters vol 107 no 18 Article ID 181802 6pages 2011
[29] P Adamson I Anghel C Backhouse et al ldquoElectron neutrinoand antineutrino appearance in the full MINOS data samplerdquoPhysical Review Letters vol 110 no 17 Article ID 171801 6 pages2013
[30] P Adamson C Andreopoulos K E Arms et al ldquoSearch foractive neutrino disappearance using neutral-current interac-tions in theMINOS long-baseline experimentrdquo Physical ReviewLetters vol 101 no 22 Article ID 221804 5 pages 2008
[31] P Adamson C Andreopoulos D J Auty et al ldquoSearch for ster-ile neutrino mixing in the MINOS long-baseline experimentrdquoPhysical Review D vol 81 no 5 Article ID 052004 18 pages2010
[32] P Adamson D J Auty D S Ayres et al ldquoActive to sterileneutrino mixing limits from neutral-current interactions inMINOSrdquo Physical Review Letters vol 107 no 1 Article ID011802 5 pages 2011
[33] Z Pavlovic Observation of disappearance of muon neutrinos inthe NuMI beam [PhD thesis] University of Texas at AustinAustin Tex USA 2008
[34] F Ballarini G Battistoni M Campanella et al ldquoThe FLUKAcode an overviewrdquo Journal of Physics vol 41 article 151 2006
[35] S Agostinelli J Allison K Amako et al ldquoGEANT4mdasha sim-ulation toolkitrdquo Nuclear Instruments and Methods in PhysicsResearch A vol 506 no 3 pp 250ndash303 2003
[36] G Battistoni F Cerutti A Fasso et al ldquoThe FLUKA codedescription and benchmarkingrdquo in Proceedings of the HadronicShower Simulation Workshop vol 896 of AIP Conference Pro-ceedings pp 31ndash49 Batavia Ill USA September 2006
[37] D G Michaele P Adamson T Alexopoulos et al ldquoThe mag-netized steel and scintillator calorimeters of the MINOS exper-imentrdquoNuclear Instruments and Methods in Physics Research Avol 596 no 2 pp 190ndash228 2008
[38] I E Stockdale A Bodek F Borcherding N Giokaris et alldquoLimits on muon-neutrino oscillations in the mass range 30 lt9987791198982lt 1000 eV2c4 rdquo Physical Review Letters vol 52 no 16 pp
1384ndash1388 1984[39] F Dydak G J Feldman C Guyot et al ldquoA search for V
120583
oscillations in the9987791198982 range 03ndash90 eV2 rdquo Physics Letters B vol134 no 3-4 pp 281ndash286 1984
[40] F Bergsma J Dorenbosch M Jonker et al ldquoA searchfor oscillations of muon neutrinos in an experiment withLEcong07 kmGeVrdquo Physics Letters B vol 142 no 1-2 pp 103ndash1101984
[41] M H Ahn E Aliu S Andringa et al ldquoMeasurement ofneutrino oscillation by the K2K experimentrdquo Physical ReviewD vol 74 no 7 Article ID 072003 39 pages 2006
[42] P Adamson T Alexopoulos W W M Allison et al ldquoFirstobservations of separated atmospheric V
120583and ]
120583events in the
MINOS detectorrdquo Physical Review D vol 73 no 7 Article ID072002 2006
[43] P Adamson C Andreopoulos K E Arms et al ldquoCharge-separated atmospheric neutrino-inducedmuons in theMINOSfar detectorrdquo Physical ReviewD vol 75 no 9 Article ID 09200314 pages 2007
[44] P Adamson C Backhouse G Barr et al ldquoMeasurements ofatmospheric neutrinos and antineutrinos in the MINOS fardetectorrdquo Physical Review D vol 86 no 5 Article ID 05200720 pages 2012
Advances in High Energy Physics 17
[45] M A Kordosky Hadronic interactions in the MINOS detectors[PhD thesis] University of Texas at Austin Austin Tex USA2004
[46] P L Vahle Electromagnetic interactions in the MINOS detectors[PhD thesis] University of Texas at Austin Austin Tex USA2004
[47] C Backhouse Measuring neutrino oscillation parameters using]120583disappearance inMINOS [PhD thesis] University of Oxford
Oxford UK 2011[48] T M Cover and P E Hart ldquoNearest neighbor pattern classifi-
cationrdquo IEEE Transactions on Information Theory vol 13 no 1pp 21ndash27 1967
[49] R Ospanov A measurement of muon neutrino disappearancewith the MINOS detectors and NuMI beam [PhD thesis]University of Texas at Austin Austin Tex USA 2008
[50] J S Marshall A study of muon neutrino disappearance with theMINOS detectors and the NuMI neutrino beam [PhD thesis]University of Cambridge Cambridge UK 2008
[51] J P OchoaA search formuon neutrino to electron neutrino oscil-lations in the MINOS Experiment [PhD thesis] The CaliforniaInstitute of Technology Pasadena Calif USA 2009
[52] R TonerMeasuring 12057913via muon neutrino to electron neutrino
oscillations in the MINOS experiment [PhD thesis] Universityof Cambridge Cambridge UK 2011
[53] A Holin Electron neutrino appearance in the MINOS experi-ment [PhD thesis] University College London London UK2010
[54] J Boehm Measurement of electron neutrino appearance withthe MINOS experiment [PhD thesis] Harvard UniversityCambridge Mass USA 2009
[55] G Tinti Sterile neutrino oscillations in MINOS and hadronproduction in pC collisions [PhD thesis] University of OxfordOxford UK 2010
[56] J J EvansMeasuring antineutrino oscillations with the MINOSexperiment [PhD thesis] University of Oxford Oxford UK2008
[57] S J ColemanAmeasurement of neutrino oscillations withmuonneutrinos in the MINOS experiment [PhD thesis] College ofWilliam ampMary Williamsburg Va USA 2011
[58] J S Mitchell Measuring ]120583disappearance with the MINOS
experiment [PhD thesis] University of Cambridge CambridgeUK 2011
[59] A McGowan Observation of deficit in NuMI neutrino-inducedrock and non-fiducial muons in MINOS far detector andmeasurement of neutrino oscillation parameters [PhD thesis]University of Minnesota Minneapolis Minn USA 2007
[60] M StraitMeasurement of neutrino oscillation parameters usinganti-fiducial charged current events in MINOS [PhD thesis]University of Minnesota Minneapolis Minn USA 2010
[61] Y Itow ldquoAtmospheric neutrinosmdashresults from running exper-imentsrdquo in Proceedings of the 25th International Conference onNeutrino Physics and Astrophysics (Neutrino rsquo12) Kyoto JapanJune 2012
[62] K Abe N Abgrall Y Ajima et al ldquoFirst muon-neutrinodisappearance study with an off-axis beamrdquo Physical Review Dvol 85 no 3 Article ID 031103 8 pages 2012
[63] K Nakamura ldquoReview of particle physicsrdquo Journal of Physics Gvol 37 Article ID 075021 2010
[64] L Wolfenstein ldquoNeutrino oscillations in matterrdquo PhysicalReview D vol 17 no 9 pp 2369ndash2374 1978
[65] J W F Valle ldquoResonant oscillations of massless neutrinos inmatterrdquo Physics Letters B vol 199 no 3 pp 432ndash436 1987
[66] M C Gonzalez-Garcia M M Guzzo P I Krastev et alldquoAtmospheric neutrino observations and flavor changing inter-actionsrdquo Physical Review Letters vol 82 no 16 pp 3202ndash32051999
[67] A Friedland C Lunardini and M Maltoni ldquoAtmosphericneutrinos as probes of neutrino-matter interactionsrdquo PhysicalReview D vol 70 no 11 Article ID 111301 2004
[68] Z IsvanAntineutrino oscillations and a Search for non-standardInteractions with the MINOS [PhD thesis] University of Pitts-burgh Pittsburgh Pa USA 2012
[69] W A Mann D Cherdack W Musial and T Kafka ldquoApparentmultiple 998779119898
32
2 in ]120583and V
120583survival oscillations from nonstan-
dard interactionmatter effectrdquo Physical Review D vol 82 no 11Article ID 113010 8 pages 2010
[70] J Kopp P A N Machado and S J Parke ldquoInterpretation ofMINOS data in terms of nonstandard neutrino interactionsrdquoPhysical Review D vol 82 no 11 Article ID 113002 12 pages2010
[71] J A B Coelho Investigacao de mecanismos alternativos aoscilacao de neutrinos no experimentos MINOS [PhD thesis]Universidade Estadual de Campinas Sao Paulo Brazil 2012
[72] F P An Q An J Z Bai A B Balantekin et al ldquoImprovedmeasurement of electron antineutrino disappearance at DayaBayrdquo Chinese Physics C vol 37 Article ID 011001 21 pages 2013
[73] J K Ahn S Chebotaryov J H Choi et al ldquoObservationof reactor electron antineutrinos disappearance in the RENOexperimentrdquo Physical Review Letters vol 108 Article ID 1918026 pages 2012
[74] Y Abe C Aberle J C dos Anjos et al ldquoReactor electronantineutrino disappearance in the Double Chooz experimentrdquoPhysical Review D vol 86 Article ID 052008 2012
[75] K Abe N Abgrall H Aihara et al ldquoEvidence of electronneutrino appearance in a muon neutrino beamrdquo PhysicalReview D vol 88 no 3 Article ID 032002 41 pages 2013
[76] A Schreckenberger Electron neutrino and antineutrino appear-ance in the MINOS detector [PhD thesis] University of Min-nesota Minneapolis Minn USA 2013
[77] D J Koskinen MINOS sterile neutrino search [PhD thesis]University College London London UK 2009
[78] M Apollonio A Baldini C Bemporad et al ldquoSearch forneutrino oscillations on a long base-line at the CHOOZ nuclearpower stationrdquoTheEuropean Physical Journal C vol 27 pp 331ndash374 2003
[79] G Tzanankos M Bishai M Diwan et alMINOS+ a proposalto FNAL to run MINOS with the medium energy NuMI beam[PhD thesis] University of Athens Athens Greece 2011
[80] A Aguilar L B Auerbach R L Burman et al ldquoEvidence forneutrino oscillations from the observation of ]
119890e appearance
in a ]120583beamrdquo Physical Review D vol 64 Article ID 112007 22
pages 2001[81] A A Aguilar-Arevalo C E Anderson S J Brice et al ldquoSearch
for electron antineutrino appearance at the Δ119898 sim 1 eV2 ScalerdquoPhysical Review Letters vol 103 no 11 Article ID 111801 2009
[82] A A Aguilar-Arevalo C E Anderson A O Bazarko et alldquoImproved search for V
120583rarr V119890oscillations in the MiniBooNE
experimentrdquo Physical Review Letter vol 110 no 10 Article ID161801 2013
[83] GMentionM Fechner T Lasserre et al ldquoReactor antineutrinoanomalyrdquo Physical Review D vol 83 Article ID 073006 20pages 2011
18 Advances in High Energy Physics
[84] KNAbazajianMAAcero S KAgarwalla et al ldquoLight sterileneutrinos a white paperrdquo httparxivorgabs12045379
[85] B Achkar R Aleksan M Avenier et al ldquoSearch for neutrinooscillations at 15 40 and 95meters from a nuclear power reactorat Bugeyrdquo Nuclear Physics B vol 434 no 3 pp 503ndash532 1995
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
High Energy PhysicsAdvances in
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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
FluidsJournal of
Atomic and Molecular Physics
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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in Condensed Matter Physics
OpticsInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
AstronomyAdvances in
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Superconductivity
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Statistical MechanicsInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
GravityJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
AstrophysicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Physics Research International
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Solid State PhysicsJournal of
Computational Methods in Physics
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Soft MatterJournal of
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PhotonicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Biophysics
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
ThermodynamicsJournal of
8 Advances in High Energy Physics
20
40
60
80
100
120
0 10 15 20 30 50
Even
tstimes10
4(G
eV)
MINOS near detector dataMCMC uncertaintyNC background
MINOS near detectorLow energy beam 120583-mode729 times 1020 POT
Reconstructed 120583 energy (GeV)5
Figure 9 The energy spectrum of ]120583CC interactions observed in
the ND compared to the simulation
systematic uncertainties the energy spectra of the ]120583and
]120583CC interactions observed in the ND (shown in Figure 9
for the neutrino-dominated beam) are used to predict thespectrum at the FD in the absence of oscillation [23 56]The neutrino energy spectra at the ND and FD are notidentical the ND subtends a relatively large angle to thebeam so for each pion or kaon a range of decay anglescan produce a neutrino that passes through the detectorcorresponding to a range of neutrino energies However theFD is effectively a point when viewed from the neutrinoproduction location so a single decay angle for each hadrontherefore a single neutrino energy contributes to the fluxTo take this difference into account the hadron-decay kine-matics are encoded into a beam transfer matrix that convertsthe observed ND flux into a predicted FD flux Once theND data has been used in this way the most importantsystematic uncertainties are those that can affect the twodetectors differently primarily reconstruction efficienciesand miscalibrations of the neutrino energy measurementin the detectors [57] These uncertainties are included inthe fit that extracts the oscillation parameters [58] Theuncertainty on the reconstruction efficiency is modeled as a16 uncertainty on the relative rate of events between theND and FD The uncertainty on the measurement of muonenergy has two components that are fully correlated betweenthe detectors a 2 uncertainty on energies measured fromrange and a 3 uncertainty on energies measured fromthe curvature in the magnetic field The uncertainty in thehadronic energy measurements also has two componentsAn uncertainty arising from shower modeling uncertaintiesand calibration is fully correlated between the detectorsand is parameterized as (66 + 35119890119864shw14GeV) The secondcomponent is uncorrelated between the detectors and is 19
in theND and 11 in the FD this is dominated by calibrationuncertainties
The top row of Figure 10 shows the predicted spectra of]120583and ]120583CC interactions from the neutrino-dominated and
antineutrino-enhanced beams at the FD along with the dataIn the neutrino-dominated beam an additional sample isused consisting of neutrinos interacting outside the fiducialvolume of the detector and in the rock surrounding thedetector [59 60] This nonfiducial sample consists mainlyof high energy neutrinos and has significantly lower res-olution as not all the energy is contained in the detectorhowever it does contain some oscillation information Intotal 8100 reconstructed neutrino events are used in theanalysis without oscillations 9471 would be expected Inall samples a clear energy-dependent deficit of ]
120583and
]120583interactions is observed The ratio of the data to the
expectation for the ]120583interactions in the neutrino-dominated
beam is shown in Figure 11This ratio shows the ldquodip and riserdquoenergy dependence of the deficit which is characteristic ofoscillation and described by (1)
The bottom row of Figure 10 shows the spectra of atmo-spheric ]
120583and ]120583CC interactions as a function of 119871119864 where
119871 is the distance traveled by the neutrino and 119864 is its energyThe atmospheric neutrino events are divided into ]
120583and ]120583
interactions according to the direction of curvature of themuon and separated into samples depending on whether ornot the interaction vertex is contained in the detector
All the observed ]120583and ]120583CC interactions are fit accord-
ing to the two-flavour model of (1) under the assumptionthat neutrinos and antineutrinos have the same oscillationparametersThe resultingmeasurement of |Δ1198982| and sin2(2120579)is shown in Figure 12 The fit yields |Δ1198982| = (241
+009
minus010) times
10minus3 eV2 and sin2(2120579) = 0950
+0035
minus0036 disfavouring maximal
mixing at the 86 confidence level Figure 12 compares thismeasurement to those from Super-Kamiokande [61] andT2K [62] The MINOS measurement is the most precisedetermination of |Δ1198982| and all measurements of sin2(2120579) areconsistent
41 Muon Antineutrino Disappearance In the standardmodel of neutrino oscillation neutrinos and antineutrinosobey the same parameters with CPT symmetry requiringthat the masses of particles and antiparticles are identicalThe most sensitive test of this symmetry in other sectors isfrom the kaon system [63] The data from the antineutrino-enhanced beam and the interaction of atmospheric antineu-trinos enables the first direct comparison of the neutrinoand antineutrino oscillation parameters in the atmosphericregion This comparison provides a limit on nonstandardinteractions with the matter being passed through by theneutrino beam [64ndash70]
Figure 10 showed the energy spectra of ]120583interactions
observed in the FD These spectra can be fit in the two-flavour model of (1) allowing the antineutrino oscillationparameters to differ from those for neutrinos This fit yieldsthe antineutrino parametermeasurement shown in Figure 13|Δ1198982| = (250
+023
minus025) times 10
minus3 eV2 and sin2(2120579) = 097+003
minus008
This is in excellent agreement with the parameters measured
Advances in High Energy Physics 9
Neutrino energy (GeV) Neutrino energy (GeV) Neutrino energy (GeV)
0
20
40
60
80
0
5
10
10
15
1515
20
20
25
25
30
Muon energy (GeV)
0
200
400
600
800
0
100
200
300
400
500
6001071 times 1020 POT
Even
ts (G
eV)
Even
ts (G
eV)
Even
ts (G
eV)
Even
ts (G
eV)
120583 120583
120583120583
0 02 4 56 0 2 4 68 910 12 14 0 2 4 6 8 10 12 14
Neutrino beam Neutrino beam Neutrino beam Antineutrino beam
contained-vertex 120583
nonfiducial 120583contained-vertex 120583
contained-vertex 120583 336 times 1020 POT
(a)
0
20
40
60
0
10
20
30
0
10
20
30
0
5
10
15
20
25
MINOS dataBest fit oscillationsNo oscillations
NC backgroundCosmic-ray muons
120583 120583 120583 120583
0 1 2 3 4 0 1 2 3 4 0 1 2 3 4 0 1 2 3 4
Even
ts
Even
ts
Even
ts
Even
ts
Atmos contained-vertex 120583 Atmos nonfiducial 120583minus Atmos nonfiducial 120583+3788kton-years
Atmos contained-vertex 120583
log10( (km)E (GeV)) log10( (km)E120583 (GeV))L L log10( (km)E (GeV))L log10( (km)E120583 (GeV))L
(b)
Figure 10 The energy spectra of ]120583and ]
120583CC interactions observed at the FD compared to the expectation with and without oscillation
(a) shows beam-induced neutrinos (b) shows atmospheric neutrinos
with neutrinos alone (the red line in Figure 13) It should benoted that the first MINOS measurement of the antineutrinooscillation parameters released in 2010 [17] yielded a notabletension between the ] and ] oscillation parameters whichwere in agreement only at the 20 confidence levelThis ten-sion was shown to be a statistical fluctuation as the additionof further data brought the ] and ] parameters measurementsinto good agreement [19 20]
5 Electron Neutrino andAntineutrino Appearance
A search for ]119890and ]
119890appearance in the ]
120583and ]
120583beams
enables a measurement of the mixing angle 12057913 It is critical
to know the level of background to the ]119890sample in the
FD The energy spectrum of background events measured inthe ND is used to predict the spectrum expected in the FDHowever the background consists of three components NCinteractions CC ]
120583and ]
120583interactions and the intrinsic ]
119890
component in the beam The relative contribution betweenthe ND and FD is different for all of these components sincethey are affected differently by oscillation and the kinematicsof the production in the beam are different Therefore each
backgroundmust be individually measuredTheNuMI beamcan be configured to produce neutrino beams of varyingenergy by altering the current passing through the magnetichorns and changing the relative positions of the target andhorns Between these different beam configurations therelative contributions of the three background componentschange in a well-understood way as shown in Figure 15By comparing the ND data to the simulation in the threedifferent beam configurations shown in the figure the contri-butions of the three background components can be extracted[71]
Using the data-driven background extraction procedurea total of 1277 background events are expected at the FDin the neutrino-dominated beam and 175 events in theantineutrino-enhanced beam In the data 152 and 20 eventsare observed respectively Figure 16 shows the energy spectraof these events divided into bins of the library eventmatchingdiscriminant variable Although CC ]
119890and ]119890events cannot
be separated on an event-by-event basis the change inthe relative numbers of neutrino and antineutrino inter-actions between the neutrino-dominated and antineutrino-enhanced beams is well knownThis allows separate limits tobe placed on the rates of ]
120583rarr ]119890and ]120583rarr ]119890transitions
on a statistical basis
10 Advances in High Energy PhysicsRa
tio to
no
osci
llatio
ns
05
1
15
2
25
0 10 15 20 30 50
MINOS far detector data
5Reconstructed 120583 energy (GeV)
1071 times 1020 POT
Prediction Δm2 = 241 times 10minus3eV2
Low energy beam 120583-mode
Figure 11 The ratio of the observed ]120583energy spectrum to the
expectation in the case of no oscillation in the neutrino-dominatedbeam The black points show the data the blue line shows the bestfit to the data
075 080 085 090 095 10015
20
25
30
35
40
90 CL68 CL
90 CL
sin2(2120579)
|Δm
2|(10minus3eV
2)
MINOS 3788 kt-yr atmospheric
336 times 1020 POT 120583 modeSuper-K zenith anglelowast
Super-K LElowast
T2Klowastlowast
lowastNeutrino 2012lowastlowastPRD 85 031103(R) (2012)
1071 times 1020 POT 120583 mode
Figure 12 The allowed regions for the atmospheric oscillationparameters |Δ1198982| and sin2(2120579) assuming identical neutrino andantineutrino oscillation parametersTheMINOS result is comparedto measurements from Super-Kamiokande [61] and T2K [62]
The data are fit to extract a measurement of 12057913 The
resulting measurement is shown in Figure 17 The measuredvalue of 120579
13depends on the CP violating phase 120575 which
directly affects the ]119890and ]
119890appearance probabilities and
themass hierarchy which affects the appearance probabilitiesthrough the interactions of the neutrinos with the matter in
MINOS 120583 disappearance1071 times 1020 POT 120583 mode336 times 1020 POT mode3788kt-yr atmospheric
90 CL120583120583120583 + 120583
120583120583120583 + 120583
Best fit
sin2(2120579) or sin2(2120579)
(|Δm
2|
or Δ
m2|)
(10minus3eV
2)
075 080 085 090 095 100
20
25
30
35
120583
|Figure 13 The allowed region for antineutrino oscillation param-eters (blue line) compared to the region measured with neutrinosalone (red line) and the region measured using both neutrinos andantineutrinos under the assumption they have the same parameters(black line)
20
25
30
20 25 30
|Δm
2| (10
minus3eV
2)
|Δm2| (10minus3eV2)
68 CL|Δm2| = |Δm2|
MINOS 120583 disappearance1071 times 1020 POT 120583 mode336 times 1020 POT mode3788kt-yr atmospheric
90 CLBest fit
120583
Figure 14 A comparison of the measured limits on the masssplittings of neutrinos and antineutrinos
the Earthrsquos crust Assuming a normal mass hierarchy 120575 = 0and 120579
23lt 1205874 MINOS measures 2sin2(2120579
13)sin2(120579
23) =
0051+0038
minus0030 Assuming an inverted mass hierarchy 120575 = 0
and 12057923
lt 1205874 MINOS measures 2sin2(212057913)sin2(120579
23) =
0093+0054
minus0049 This measurement is consistent with the results
from reactor neutrino searches [72ndash74] and the T2K experi-ment [75]
This MINOS measurement is the first ever search for ]119890
appearance in a long-baseline ]120583beam and the first search
Advances in High Energy Physics 11
Reconstructed energy (GeV)0 6 8
Frac
tion
of ev
ents
0
01
02
03
04
Standard MC
MINOS
2 4
Near detector 2011
NC120583-CCe-CC
(a)
Horn-off MC
Reconstructed energy (GeV)0 6 8
Frac
tion
of ev
ents
0
01
02
03
04 MINOS
2 4
Near detector 2011
NC120583-CCe-CC
(b)
High energy MC
Reconstructed energy (GeV)0 6 8
Frac
tion
of ev
ents
0
01
02
03
04 MINOS
2 4
Near detector 2011
NC120583-CCe-CC
(c)
Figure 15 The contribution of the three components to the background in the ]119890appearance search as simulated in the ND (a) the regular
(low energy) beam data (b) with no current in the NuMI focusing horns (c) a high energy beam configuration
for ]119890and ]119890appearance with significant matter effects Both
of these effects provide some sensitivity to the neutrinomass hierarchy and CP violation when the MINOS data iscompared to the measurements made by reactor neutrinosearches [72ndash74] (we have calculated a limit of sin2(2120579
13) =
0098 plusmn 0013 from the reactor data at the time of analysis)The sensitivity of MINOS to the mass hierarchy and CPviolation is modest but this contributes to the first analysisof the type that will be used by all future long-baselineexperiments The resulting values of the likelihood by whichMINOS disfavours various values of these parameters areshown in Figure 18 [76]
6 Search for Sterile Neutrino Mixing UsingNeutral-Current Interactions
The energy spectrum of NC interactions in the FD should beunchanged by standard neutrino oscillationThe existence ofone or more sterile neutrino flavours ]
119904 could cause a deficit
in the observed NC interaction rate As with all the MINOSoscillation analyses the energy spectrum of NC interactionsobserved in the ND (which was shown in Figure 8) is usedto predict the spectrum expected at the FD [77] The FDexpectation is shown in Figure 19 with the dashed blue linetaking into account ]
119890appearance corresponding to 120579
13=
115∘ (at the limit set by CHOOZ [78] and a little above
the current accepted value [29 72ndash75] this analysis usesonly the first 707 times 10
20 protons on target of data andwas performed before the recent positive measurements ofa nonzero 120579
13) The data are also shown in the figure and
are in good agreement with the expectation confirming thestandard model of neutrino oscillation This agreement canbe quantified using a test statistic 119877
119877 =119873data minus 119861CC
119878NC (7)
where 119873data is the number of events observed 119861CC is thepredicted background of CC interactions and 119878NC is the
predicted number of NC interactions A value of 119877 = 101 plusmn
006(stat) plusmn 005(syst) is obtained (over the full energy range0ndash120GeV) which is in good agreement with the expectationof 119877 = 1 in the case of no mixing with sterile neutrinos
The data are analysed with a model that assumes a singlesterile neutrino flavour mixing through the addition of afourth neutrino mass state119898
4≫ 1198983 This introduces a mass
splitting Δ119898243
with magnitude O(1 eV2) such that no oscil-lation-induced change to the event rate is observed at theND and the oscillatory energy dependence of the induceddepletion at the FD is so rapid that an overall uniform deple-tion is observed once the energy resolution of the detectors isaccounted forThismodel introduces three additionalmixingangles 120579
14 12057924 and 120579
34 MINOS is insensitive to 120579
14but sets
limits of 12057924= (00
+5
minus00)∘ and 120579
34= (00
+25
minus00)∘ These limits are
evaluated assuming 12057913at the CHOOZ limit
The limit on the coupling of sterile to active neutrinos canbe quantified by defining 119891
119904 the fraction of disappearing ]
120583
which have oscillated into ]119904
119891119904=
119875]120583rarr ]119904
1 minus 119875]120583rarr ]120583
(8)
For the model used in which 1198984≫ 119898
3 119891119904is evaluated
at 14 GeV the energy of maximal ]120583disappearance To
determine the limit on 119891119904 a large number of test values
are chosen of the mixing angles 12057924 12057934 and 120579
23 from
Gaussian distributions according to the measured values and1120590 uncertainties given above (with 120579
23constrained from the
measurements with CC ]120583interactions) 119891
119904is calculated for
each case and the value of 119891119904that is larger than 90 of the
test cases represents the limit MINOS limits 119891119904lt 040 at the
90 confidence level
7 The Future MINOS+
The MINOS experiment has made some very importantcontributions to our understanding of neutrino oscillation
12 Advances in High Energy Physics
Reconstructed energy (GeV)
Reconstructed energy (GeV)
Even
ts
30
0
10
20
Even
ts
30
0
10
20
Even
ts
30
0
10
20
2 4 6 8
2 4 6 8
Reconstructed energy (GeV)2 4 6 8
06 lt 120572LEM lt 07
MINOS far detector data
07 lt 120572LEM lt 08
120572LEM gt 08
mode
mode
mode
e CC signal
e CC signalBackgroundData
(a)
Even
ts
Reconstructed energy (GeV)2 4 6 8
Reconstructed energy (GeV)2 4 6 8
Reconstructed energy (GeV)2 4 6 8
06 lt 120572LEM lt 07
MINOS far detector data
Merged for fit
07 lt 120572LEM lt 08
120572LEM gt 08
mode
mode
mode
8
6
4
2
0
Even
ts
8
6
4
2
0
Even
ts
8
6
4
2
0
e CC signal
e CC signalBackgroundData
5ndash8GeV bins
(b)
Figure 16 The CC ]119890(a) and ]
119890(b) candidate events selected in the FD compared to the expectation without any ]
119890appearance (red) and
with the best fit for 12057913(purple) The events are divided into bins of the library event matching discriminant variable
Advances in High Energy Physics 13
20
15
10
05
000 01 02 03 04
2sin2(212057913)sin212057923
Δm2 gt 0
sin
120575(120587)
(a)
20
15
10
05
000 01 02 03 04
2sin2(212057913)sin212057923
MINOS best fit 12057923 lt 1205874
MINOS best fit 12057923 gt 1205874
Δm2 lt 0
MINOS
106 times 1020 POT -mode33 times 1020 POT -mode
68 CL 12057923 lt 1205874
90 CL 12057923 lt 1205874
120575(120587)
(b)
Figure 17 The allowed regions for 2sin2(212057913)sin2(120579
23)
120575(120587)
Δm2 gt 0 12057923 gt 1205874
Δm2 gt 0 12057923 lt 1205874
Δm2 lt 0 12057923 gt 1205874Δm2 lt 0 12057923 lt 1205874
3
2
1
00 1 1505 2
MINOS
90 CL
68 CL
minus2Δ
(L)
ln
Figure 18 The values of likelihood 119871 by which various values oftheCP violating parameter 120575 the mass hierarchy and the octant of12057923are disfavouredThis analysis uses MINOS data and information
from reactor neutrino measurements of 12057913[72ndash74]
physics and has finished taking data with the low energybeam for which it was designed However the experimentwill continue taking data and producing new results for thenext few years as MINOS+ [79] The NuMI beam is being
20
2018161410 12
Far detector data
Even
ts (G
eV)
00 2 4 6 8
40
60
80
100
120
140
12057913 = 0∘
12057913 = 115∘ 120575 = 120587 Δm232 gt 0
120583 CC background|Δm2
32| = 232 times 10minus3eV2
Ereco (GeV)
sin2212057923 = 1
Figure 19 The black dots show the energy spectrum of NCinteractions observed in the far detector The red lines show theexpectation in the case of no sterile neutrinos and 120579
13= 0 the blue
dashed line shows the same expectation with 12057913= 115
∘
upgraded to a higher energy and intensity for the NO]Aexperiment the far detector of which will sit 14 mrad offaxisNO]A will receive a narrow-band beam peaking at around2GeV which is ideal for searching for ]
119890appearance since
the background seen in MINOS from NC interactions ofhigh energy neutrinos will be heavily reduced Figure 20shows that the MINOS FD will see an intense ]
120583beam
14 Advances in High Energy Physics
1000
500
00 5 10 15 20
E (GeV)
MINOS+NOAMINOS
Preliminary
Simulated beam54 kton 6 times 1020 POT
120583CC
even
ts (G
eV)
Figure 20 The ]120583energy spectrum that will be observed by the
MINOS+ FD compared to the spectra observed by MINOS andNO]A
peaking at around 7GeV In this configuration MINOS+ willobserve around 4000 CC ]
120583interactions in the FD each
year unprecedented statistics for a long-baseline oscillationexperimentThis will offer a unique high precision test of thethree-flavour oscillation paradigm
MINOS+ will be able to make a very sensitive searchfor the sterile neutrinos suggested by the LSND [80] andMiniBooNE [81 82] data and by some interpretations ofreactor neutrino data [83] This search will cover more thanthree orders of magnitude in the mass splitting between thesterile and active neutrinos The signal that MINOS+ willsearch for is illustrated in Figure 21 Figure 21(a) illustratesthe increase in statistical precision thatMINOS+will provideon the ratio of the observed CC ]
120583interaction rate to
that expected without oscillations Figure 21(b) shows howthis ratio is modified if a sterile neutrino exists and mixeswith the active neutrinos an additional deficit of muonneutrino interactions occurs in the higher energy region ofthe spectrum In the model assumed here which introducesa single sterile neutrino state three new mixing angles areintroduced 120579
14 12057924 and 120579
34 An additional mass splitting
Δ1198982
43is also introduced The position in energy of the
additional deficit is governed by the value of the new masssplittingThemagnitude of the additional deficit in the CC ]
120583
interaction rate is governed primarily by the size of 12057924 this is
in comparison to short-baseline searches for ]119890disappearance
from reactors which are governed by 12057914and searches for ]
119890
appearance in ]120583beamswhich are governed by a combination
of 12057914
and 12057924 A detailed explanation of the global effort to
search for sterile neutrinos can be found in [84]The sensitivity of the MINOS+ experiment when com-
bined with the Bugey reactor neutrino data [85] is shown in
MINOS+ simulation
MINOS 1071 times 1021 POT06 times 1021 POT12 times 1021 POT18 times 1021 POT
120583su
rviv
al p
roba
bilit
y
Neutrino energy (GeV)0 5 10 15
15
1
05
0
(a)
P(
120583rarr
120583)
No sterile neutrinosΔm2
43 = 2 times 10minus2eV2 sin2(212057924) = 02
0 5 10 15 20
1
0
18
06
04
02
Neutrino energy (GeV)
(b)
Figure 21 (a) The black points show the ratio of the observed ]120583
energy spectrum to the expectation in the case of no oscillation inthe neutrino-dominated beam of MINOS The blue region showsthe statistical precision expected from MINOS+ (b) The black lineshows the muon neutrino survival probability in the case of nosterile neutrinos the red line shows how the probability would bemodified by the addition of mixing with a sterile neutrino
Figure 22 MINOS+ has the potential to rule out much of theLSND allowed region MINOS+ will begin taking data in thelate summer of 2013 and will continue taking data for at leasttwo years (Figure 22 assumes two years of data taking with aneutrino-dominated beam)
8 Conclusion
The MINOS experiment was conceived at a time when neu-trino oscillation had only recently been confirmed as thesolution to the problem of neutrino flavour change It has
Advances in High Energy Physics 15
Δm
2
10minus210minus2
10minus1
10minus1
10minus310minus4 1
1
10
102
LSND 90 CLLSND 99 CLKarmen2 90 CLBugey 90 CLlowast
MiniBooNE 90 CLMiniBooNE 99 CLMINOS+ and Bugeycombination 90 CL
sin22120579120583e
lowastGLoBES 2012 fit with new reactor fluxescourtesy of P Huber
Figure 22 The sensitivity of MINOS+ to the existence of sterileneutrinos when combined with data from the Bugey [85] reactorneutrino experiment Δ1198982 is the splitting between the three knownneutrino mass states and a new fourth state 120579
120583119890is the mixing angle
governing ]120583rarr ]119890transitions when a fourth sterile neutrino state
is introduced into the PMNSmixingmatrixThis figure assumes twoyears of MINOS+ running with a neutrino-dominated beam
played a hugely influential role in bringing neutrino oscilla-tion physics into an era of precision measurement MINOSrsquosmeasurement of the largest neutrino mass splitting is themost precise in the world MINOS has made the first directprecision measurement of the corresponding antineutrinoparameters a measurement that promises to remain theworldrsquos most precise for many years And MINOS has playeda role in the discovery of a nonzero value for 120579
13
Now that the value of 12057913is known the neutrino physics
community can move on to determine the neutrino masshierarchy and to search for CP violation in the neutrinosector MINOS has pioneered a number of techniques thatwill be used by future experiments The two-detector setupall important in reducing the impact of systematic uncer-tainties is the design of choice for any new experiment andMINOS has demonstrated methods of using a near detectorto determine the expectation at a far detector MINOS hasperformed the first search for ]
119890appearance in a ]
120583beam
and the first search for ]119890and ]119890appearance with significant
matter effects demonstrating the analysis techniques that willbe used to determine the mass hierarchy and CP violationparameter
In the second half of 2013 MINOS will begin taking dataas the MINOS+ experiment which will make ever more pre-cise tests of the three-flavour neutrino oscillation paradigmand set world-leading limits on the existence of sterileneutrinos This is an exciting future for an experiment thatwith a decade of data taking so far has already created alasting legacy for itself in our understanding of the neutrino
A comparison of themeasured neutrino and antineutrinomass splittings is shown in Figure 14 the difference betweenthe two is constrained to |Δ119898
2| minus |Δ119898
2| = (012
+024
minus026) times
10minus3 eV2
Acknowledgment
The work of the MINOS and MINOS+ collaborations issupported by the US DoE the UK STFC the US NSF theState and University of Minnesota the University of Athensin Greece and Brazilrsquos FAPESP and CNPq The authors aregrateful to the Minnesota Department of Natural Resourcesthe crew of the Soudan Underground Laboratory and thepersonnel of Fermilab for their vital contributions
References
[1] S Wojcicki ldquoLong baseline neutrino oscillation programe inthe United Statesrdquo Nuclear Physics B vol 77 no 1ndash3 pp 182ndash186 1999 Proceedings of the 18th International Conference onNeutrino Physics and Astrophysics (Neutrino rsquo98) TakayamaJapan June 1998
[2] R Davis Jr D S Harmer and K C Hoffman ldquoSearch forneutrinos from the sunrdquo Physical Review Letters vol 20 no 21pp 1205ndash1209 1968
[3] A I Abazov O L Anosov E L Faizov et al ldquoSearch forneutrinos from sun using the reactionGa-71 (electron-neutrinoe-) Ge-71rdquo Physical Review Letters vol 67 pp 3332ndash3335 1991
[4] P Anselmann W Hampel G Heusser et al ldquoSolar neutrinosobserved by GALLEX at gran sassordquo Physics Letters B vol 285no 4 pp 376ndash389 1992
[5] M Aglietta G Battistoni E Bellotti et al ldquoExperimentalstudy of atmospheric neutrino flux in the NUSEX experimentrdquoEurophysics Letters vol 8 no 7 article 611 1989
[6] K S Hirata ldquoObservation of a small atmospheric V120583V119890ratio in
Kamiokanderdquo Physics Letters B vol 280 no 1-2 pp 146ndash1521992
[7] R Becker-Szendy C B Bratton D Casper et al ldquoElectron-and muon-neutrino content of the atmospheric fluxrdquo PhysicalReview D vol 46 pp 3720ndash3724 1992
[8] K Daum W Rhode P Bareyre et al ldquoDetermination ofthe atmospheric neutrino spectra with the frejus detectorrdquoZeitschrift fur Physik C vol 66 no 3 pp 417ndash428 1995
[9] S Ahlen M Ambrosio R Antolini and G Auriemma ldquoAtmo-spheric neutrino flux measurement using upgoing muonsrdquoPhysics Letters B vol 357 no 3 pp 481ndash486 1995
[10] WMAllison G J Alner D S Ayres et al ldquoMeasurement of theatmospheric neutrino flavour composition in Soudan 2rdquoPhysicsLetters B vol 391 no 3-4 pp 491ndash500 1997
16 Advances in High Energy Physics
[11] Y Fukuda T Hayakawa E Ichihara et al ldquoEvidence foroscillation of atmospheric neutrinosrdquo Physical Review Lettersvol 81 no 8 pp 1562ndash1567 1998
[12] Q R Ahmad R C Allen T C Andersen et al ldquoMeasurementof charged current interactions produced by solar neutrinos atthe sudbury neutrino observatoryrdquo Physical Review Letters vol87 Article ID 071301 2001
[13] Q R Ahmad R C Allen T C Andersen et al ldquoDirect evidencefor neutrino flavor transformation from neutral-current inter-actions in the sudbury neutrino observatoryrdquo Physical ReviewLetters vol 89 Article ID 011301 6 pages 2002
[14] B Pontecorvo ldquoInverse beta processes and nonconservation oflepton chargerdquo Journal of Experimental and Theoretical Physicsvol 34 pp 172ndash173 1958
[15] V N Gribov and B Pontecorvo ldquoNeutrino astronomy andlepton chargerdquo Physics Letters B vol 28 pp 493ndash496 1969
[16] Z Maki M Nakagawa and S Sakata ldquoRemarks on the unifiedmodel of elementary particlesrdquo Progress of Theoretical Physicsvol 28 no 5 pp 870ndash880 1962
[17] P Adamson C Andreopoulos D J Auty et al ldquoFirst directobservation of muon antineutrino disappearancerdquo PhysicalReview Letters vol 107 no 2 Article ID 021801 2011
[18] P Adamson D J Auty D S Ayres et al ldquoSearch for thedisappearance of muon antineutrinos in the NuMI neutrinobeamrdquo Physical Review D vol 84 no 7 Article ID 071103 6pages 2011
[19] P Adamson D S Ayres C Backhouse et al ldquoImprovedmeasurement of muon antineutrino disappearance inMINOSrdquoPhysical Review Letters vol 108 no 19 Article ID 191801 5pages 2012
[20] P Adamson I Anghel C Backhouse et al ldquoMeasurementof Neutrino and Antineutrino Oscillations Using Beam andAtmospheric Data in MINOSrdquo Physical Review Letters vol 110no 25 Article ID 251801 6 pages 2013
[21] K Anderson B Bernstein D Boehnlein et al ldquoThe NuMIFacility Technical Design Reportrdquo FERMILAB-DESIGN-1998-01 1998
[22] D G Michael P Adamson T Alexopoulos et al ldquoObservationof muon neutrino disappearance with the MINOS detectors inthe NuMI neutrino beamrdquo Physical Review Letters vol 97 no19 Article ID 191801 6 pages 2006
[23] P Adamson C Andreopoulos K E Arms et al ldquoStudy ofmuon neutrino disappearance using the fermilab main injectorneutrino beamrdquo Physical Review D vol 77 no 7 Article ID072002 34 pages 2008
[24] P Adamson C Andreopoulos K E Arms et al ldquoMeasurementof neutrino oscillations with theMINOS detectors in the NuMIbeamrdquo Physical Review Letters vol 101 no 13 Article ID 1318025 pages 2008
[25] P Adamson C Andreopoulos R Armstrong et al ldquoMea-surement of the neutrino mass splitting and flavor mixing byMINOSrdquo Physical Review Letters vol 106 no 18 Article ID181801 6 pages 2011
[26] P Adamson C Andreopoulos K E Arms et al ldquoSearch formuon-neutrino to electron-neutrino transitions in MINOSrdquoPhysical Review Letters vol 103 no 26 Article ID 261802 5pages 2009
[27] PAdamsonCAndreopoulosD J Auty et al ldquoNew constraintsonmuon-neutrino to electron-neutrino transitions inMINOSrdquoPhysical ReviewD vol 82 no 5 Article ID 051102 6 pages 2010
[28] P Adamson D J Auty D S Ayres et al ldquoImproved search formuon-neutrino to electron-neutrino oscillations in MINOSrdquoPhysical Review Letters vol 107 no 18 Article ID 181802 6pages 2011
[29] P Adamson I Anghel C Backhouse et al ldquoElectron neutrinoand antineutrino appearance in the full MINOS data samplerdquoPhysical Review Letters vol 110 no 17 Article ID 171801 6 pages2013
[30] P Adamson C Andreopoulos K E Arms et al ldquoSearch foractive neutrino disappearance using neutral-current interac-tions in theMINOS long-baseline experimentrdquo Physical ReviewLetters vol 101 no 22 Article ID 221804 5 pages 2008
[31] P Adamson C Andreopoulos D J Auty et al ldquoSearch for ster-ile neutrino mixing in the MINOS long-baseline experimentrdquoPhysical Review D vol 81 no 5 Article ID 052004 18 pages2010
[32] P Adamson D J Auty D S Ayres et al ldquoActive to sterileneutrino mixing limits from neutral-current interactions inMINOSrdquo Physical Review Letters vol 107 no 1 Article ID011802 5 pages 2011
[33] Z Pavlovic Observation of disappearance of muon neutrinos inthe NuMI beam [PhD thesis] University of Texas at AustinAustin Tex USA 2008
[34] F Ballarini G Battistoni M Campanella et al ldquoThe FLUKAcode an overviewrdquo Journal of Physics vol 41 article 151 2006
[35] S Agostinelli J Allison K Amako et al ldquoGEANT4mdasha sim-ulation toolkitrdquo Nuclear Instruments and Methods in PhysicsResearch A vol 506 no 3 pp 250ndash303 2003
[36] G Battistoni F Cerutti A Fasso et al ldquoThe FLUKA codedescription and benchmarkingrdquo in Proceedings of the HadronicShower Simulation Workshop vol 896 of AIP Conference Pro-ceedings pp 31ndash49 Batavia Ill USA September 2006
[37] D G Michaele P Adamson T Alexopoulos et al ldquoThe mag-netized steel and scintillator calorimeters of the MINOS exper-imentrdquoNuclear Instruments and Methods in Physics Research Avol 596 no 2 pp 190ndash228 2008
[38] I E Stockdale A Bodek F Borcherding N Giokaris et alldquoLimits on muon-neutrino oscillations in the mass range 30 lt9987791198982lt 1000 eV2c4 rdquo Physical Review Letters vol 52 no 16 pp
1384ndash1388 1984[39] F Dydak G J Feldman C Guyot et al ldquoA search for V
120583
oscillations in the9987791198982 range 03ndash90 eV2 rdquo Physics Letters B vol134 no 3-4 pp 281ndash286 1984
[40] F Bergsma J Dorenbosch M Jonker et al ldquoA searchfor oscillations of muon neutrinos in an experiment withLEcong07 kmGeVrdquo Physics Letters B vol 142 no 1-2 pp 103ndash1101984
[41] M H Ahn E Aliu S Andringa et al ldquoMeasurement ofneutrino oscillation by the K2K experimentrdquo Physical ReviewD vol 74 no 7 Article ID 072003 39 pages 2006
[42] P Adamson T Alexopoulos W W M Allison et al ldquoFirstobservations of separated atmospheric V
120583and ]
120583events in the
MINOS detectorrdquo Physical Review D vol 73 no 7 Article ID072002 2006
[43] P Adamson C Andreopoulos K E Arms et al ldquoCharge-separated atmospheric neutrino-inducedmuons in theMINOSfar detectorrdquo Physical ReviewD vol 75 no 9 Article ID 09200314 pages 2007
[44] P Adamson C Backhouse G Barr et al ldquoMeasurements ofatmospheric neutrinos and antineutrinos in the MINOS fardetectorrdquo Physical Review D vol 86 no 5 Article ID 05200720 pages 2012
Advances in High Energy Physics 17
[45] M A Kordosky Hadronic interactions in the MINOS detectors[PhD thesis] University of Texas at Austin Austin Tex USA2004
[46] P L Vahle Electromagnetic interactions in the MINOS detectors[PhD thesis] University of Texas at Austin Austin Tex USA2004
[47] C Backhouse Measuring neutrino oscillation parameters using]120583disappearance inMINOS [PhD thesis] University of Oxford
Oxford UK 2011[48] T M Cover and P E Hart ldquoNearest neighbor pattern classifi-
cationrdquo IEEE Transactions on Information Theory vol 13 no 1pp 21ndash27 1967
[49] R Ospanov A measurement of muon neutrino disappearancewith the MINOS detectors and NuMI beam [PhD thesis]University of Texas at Austin Austin Tex USA 2008
[50] J S Marshall A study of muon neutrino disappearance with theMINOS detectors and the NuMI neutrino beam [PhD thesis]University of Cambridge Cambridge UK 2008
[51] J P OchoaA search formuon neutrino to electron neutrino oscil-lations in the MINOS Experiment [PhD thesis] The CaliforniaInstitute of Technology Pasadena Calif USA 2009
[52] R TonerMeasuring 12057913via muon neutrino to electron neutrino
oscillations in the MINOS experiment [PhD thesis] Universityof Cambridge Cambridge UK 2011
[53] A Holin Electron neutrino appearance in the MINOS experi-ment [PhD thesis] University College London London UK2010
[54] J Boehm Measurement of electron neutrino appearance withthe MINOS experiment [PhD thesis] Harvard UniversityCambridge Mass USA 2009
[55] G Tinti Sterile neutrino oscillations in MINOS and hadronproduction in pC collisions [PhD thesis] University of OxfordOxford UK 2010
[56] J J EvansMeasuring antineutrino oscillations with the MINOSexperiment [PhD thesis] University of Oxford Oxford UK2008
[57] S J ColemanAmeasurement of neutrino oscillations withmuonneutrinos in the MINOS experiment [PhD thesis] College ofWilliam ampMary Williamsburg Va USA 2011
[58] J S Mitchell Measuring ]120583disappearance with the MINOS
experiment [PhD thesis] University of Cambridge CambridgeUK 2011
[59] A McGowan Observation of deficit in NuMI neutrino-inducedrock and non-fiducial muons in MINOS far detector andmeasurement of neutrino oscillation parameters [PhD thesis]University of Minnesota Minneapolis Minn USA 2007
[60] M StraitMeasurement of neutrino oscillation parameters usinganti-fiducial charged current events in MINOS [PhD thesis]University of Minnesota Minneapolis Minn USA 2010
[61] Y Itow ldquoAtmospheric neutrinosmdashresults from running exper-imentsrdquo in Proceedings of the 25th International Conference onNeutrino Physics and Astrophysics (Neutrino rsquo12) Kyoto JapanJune 2012
[62] K Abe N Abgrall Y Ajima et al ldquoFirst muon-neutrinodisappearance study with an off-axis beamrdquo Physical Review Dvol 85 no 3 Article ID 031103 8 pages 2012
[63] K Nakamura ldquoReview of particle physicsrdquo Journal of Physics Gvol 37 Article ID 075021 2010
[64] L Wolfenstein ldquoNeutrino oscillations in matterrdquo PhysicalReview D vol 17 no 9 pp 2369ndash2374 1978
[65] J W F Valle ldquoResonant oscillations of massless neutrinos inmatterrdquo Physics Letters B vol 199 no 3 pp 432ndash436 1987
[66] M C Gonzalez-Garcia M M Guzzo P I Krastev et alldquoAtmospheric neutrino observations and flavor changing inter-actionsrdquo Physical Review Letters vol 82 no 16 pp 3202ndash32051999
[67] A Friedland C Lunardini and M Maltoni ldquoAtmosphericneutrinos as probes of neutrino-matter interactionsrdquo PhysicalReview D vol 70 no 11 Article ID 111301 2004
[68] Z IsvanAntineutrino oscillations and a Search for non-standardInteractions with the MINOS [PhD thesis] University of Pitts-burgh Pittsburgh Pa USA 2012
[69] W A Mann D Cherdack W Musial and T Kafka ldquoApparentmultiple 998779119898
32
2 in ]120583and V
120583survival oscillations from nonstan-
dard interactionmatter effectrdquo Physical Review D vol 82 no 11Article ID 113010 8 pages 2010
[70] J Kopp P A N Machado and S J Parke ldquoInterpretation ofMINOS data in terms of nonstandard neutrino interactionsrdquoPhysical Review D vol 82 no 11 Article ID 113002 12 pages2010
[71] J A B Coelho Investigacao de mecanismos alternativos aoscilacao de neutrinos no experimentos MINOS [PhD thesis]Universidade Estadual de Campinas Sao Paulo Brazil 2012
[72] F P An Q An J Z Bai A B Balantekin et al ldquoImprovedmeasurement of electron antineutrino disappearance at DayaBayrdquo Chinese Physics C vol 37 Article ID 011001 21 pages 2013
[73] J K Ahn S Chebotaryov J H Choi et al ldquoObservationof reactor electron antineutrinos disappearance in the RENOexperimentrdquo Physical Review Letters vol 108 Article ID 1918026 pages 2012
[74] Y Abe C Aberle J C dos Anjos et al ldquoReactor electronantineutrino disappearance in the Double Chooz experimentrdquoPhysical Review D vol 86 Article ID 052008 2012
[75] K Abe N Abgrall H Aihara et al ldquoEvidence of electronneutrino appearance in a muon neutrino beamrdquo PhysicalReview D vol 88 no 3 Article ID 032002 41 pages 2013
[76] A Schreckenberger Electron neutrino and antineutrino appear-ance in the MINOS detector [PhD thesis] University of Min-nesota Minneapolis Minn USA 2013
[77] D J Koskinen MINOS sterile neutrino search [PhD thesis]University College London London UK 2009
[78] M Apollonio A Baldini C Bemporad et al ldquoSearch forneutrino oscillations on a long base-line at the CHOOZ nuclearpower stationrdquoTheEuropean Physical Journal C vol 27 pp 331ndash374 2003
[79] G Tzanankos M Bishai M Diwan et alMINOS+ a proposalto FNAL to run MINOS with the medium energy NuMI beam[PhD thesis] University of Athens Athens Greece 2011
[80] A Aguilar L B Auerbach R L Burman et al ldquoEvidence forneutrino oscillations from the observation of ]
119890e appearance
in a ]120583beamrdquo Physical Review D vol 64 Article ID 112007 22
pages 2001[81] A A Aguilar-Arevalo C E Anderson S J Brice et al ldquoSearch
for electron antineutrino appearance at the Δ119898 sim 1 eV2 ScalerdquoPhysical Review Letters vol 103 no 11 Article ID 111801 2009
[82] A A Aguilar-Arevalo C E Anderson A O Bazarko et alldquoImproved search for V
120583rarr V119890oscillations in the MiniBooNE
experimentrdquo Physical Review Letter vol 110 no 10 Article ID161801 2013
[83] GMentionM Fechner T Lasserre et al ldquoReactor antineutrinoanomalyrdquo Physical Review D vol 83 Article ID 073006 20pages 2011
18 Advances in High Energy Physics
[84] KNAbazajianMAAcero S KAgarwalla et al ldquoLight sterileneutrinos a white paperrdquo httparxivorgabs12045379
[85] B Achkar R Aleksan M Avenier et al ldquoSearch for neutrinooscillations at 15 40 and 95meters from a nuclear power reactorat Bugeyrdquo Nuclear Physics B vol 434 no 3 pp 503ndash532 1995
Submit your manuscripts athttpwwwhindawicom
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Advances in Condensed Matter Physics
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Superconductivity
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Statistical MechanicsInternational Journal of
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ThermodynamicsJournal of
Advances in High Energy Physics 9
Neutrino energy (GeV) Neutrino energy (GeV) Neutrino energy (GeV)
0
20
40
60
80
0
5
10
10
15
1515
20
20
25
25
30
Muon energy (GeV)
0
200
400
600
800
0
100
200
300
400
500
6001071 times 1020 POT
Even
ts (G
eV)
Even
ts (G
eV)
Even
ts (G
eV)
Even
ts (G
eV)
120583 120583
120583120583
0 02 4 56 0 2 4 68 910 12 14 0 2 4 6 8 10 12 14
Neutrino beam Neutrino beam Neutrino beam Antineutrino beam
contained-vertex 120583
nonfiducial 120583contained-vertex 120583
contained-vertex 120583 336 times 1020 POT
(a)
0
20
40
60
0
10
20
30
0
10
20
30
0
5
10
15
20
25
MINOS dataBest fit oscillationsNo oscillations
NC backgroundCosmic-ray muons
120583 120583 120583 120583
0 1 2 3 4 0 1 2 3 4 0 1 2 3 4 0 1 2 3 4
Even
ts
Even
ts
Even
ts
Even
ts
Atmos contained-vertex 120583 Atmos nonfiducial 120583minus Atmos nonfiducial 120583+3788kton-years
Atmos contained-vertex 120583
log10( (km)E (GeV)) log10( (km)E120583 (GeV))L L log10( (km)E (GeV))L log10( (km)E120583 (GeV))L
(b)
Figure 10 The energy spectra of ]120583and ]
120583CC interactions observed at the FD compared to the expectation with and without oscillation
(a) shows beam-induced neutrinos (b) shows atmospheric neutrinos
with neutrinos alone (the red line in Figure 13) It should benoted that the first MINOS measurement of the antineutrinooscillation parameters released in 2010 [17] yielded a notabletension between the ] and ] oscillation parameters whichwere in agreement only at the 20 confidence levelThis ten-sion was shown to be a statistical fluctuation as the additionof further data brought the ] and ] parameters measurementsinto good agreement [19 20]
5 Electron Neutrino andAntineutrino Appearance
A search for ]119890and ]
119890appearance in the ]
120583and ]
120583beams
enables a measurement of the mixing angle 12057913 It is critical
to know the level of background to the ]119890sample in the
FD The energy spectrum of background events measured inthe ND is used to predict the spectrum expected in the FDHowever the background consists of three components NCinteractions CC ]
120583and ]
120583interactions and the intrinsic ]
119890
component in the beam The relative contribution betweenthe ND and FD is different for all of these components sincethey are affected differently by oscillation and the kinematicsof the production in the beam are different Therefore each
backgroundmust be individually measuredTheNuMI beamcan be configured to produce neutrino beams of varyingenergy by altering the current passing through the magnetichorns and changing the relative positions of the target andhorns Between these different beam configurations therelative contributions of the three background componentschange in a well-understood way as shown in Figure 15By comparing the ND data to the simulation in the threedifferent beam configurations shown in the figure the contri-butions of the three background components can be extracted[71]
Using the data-driven background extraction procedurea total of 1277 background events are expected at the FDin the neutrino-dominated beam and 175 events in theantineutrino-enhanced beam In the data 152 and 20 eventsare observed respectively Figure 16 shows the energy spectraof these events divided into bins of the library eventmatchingdiscriminant variable Although CC ]
119890and ]119890events cannot
be separated on an event-by-event basis the change inthe relative numbers of neutrino and antineutrino inter-actions between the neutrino-dominated and antineutrino-enhanced beams is well knownThis allows separate limits tobe placed on the rates of ]
120583rarr ]119890and ]120583rarr ]119890transitions
on a statistical basis
10 Advances in High Energy PhysicsRa
tio to
no
osci
llatio
ns
05
1
15
2
25
0 10 15 20 30 50
MINOS far detector data
5Reconstructed 120583 energy (GeV)
1071 times 1020 POT
Prediction Δm2 = 241 times 10minus3eV2
Low energy beam 120583-mode
Figure 11 The ratio of the observed ]120583energy spectrum to the
expectation in the case of no oscillation in the neutrino-dominatedbeam The black points show the data the blue line shows the bestfit to the data
075 080 085 090 095 10015
20
25
30
35
40
90 CL68 CL
90 CL
sin2(2120579)
|Δm
2|(10minus3eV
2)
MINOS 3788 kt-yr atmospheric
336 times 1020 POT 120583 modeSuper-K zenith anglelowast
Super-K LElowast
T2Klowastlowast
lowastNeutrino 2012lowastlowastPRD 85 031103(R) (2012)
1071 times 1020 POT 120583 mode
Figure 12 The allowed regions for the atmospheric oscillationparameters |Δ1198982| and sin2(2120579) assuming identical neutrino andantineutrino oscillation parametersTheMINOS result is comparedto measurements from Super-Kamiokande [61] and T2K [62]
The data are fit to extract a measurement of 12057913 The
resulting measurement is shown in Figure 17 The measuredvalue of 120579
13depends on the CP violating phase 120575 which
directly affects the ]119890and ]
119890appearance probabilities and
themass hierarchy which affects the appearance probabilitiesthrough the interactions of the neutrinos with the matter in
MINOS 120583 disappearance1071 times 1020 POT 120583 mode336 times 1020 POT mode3788kt-yr atmospheric
90 CL120583120583120583 + 120583
120583120583120583 + 120583
Best fit
sin2(2120579) or sin2(2120579)
(|Δm
2|
or Δ
m2|)
(10minus3eV
2)
075 080 085 090 095 100
20
25
30
35
120583
|Figure 13 The allowed region for antineutrino oscillation param-eters (blue line) compared to the region measured with neutrinosalone (red line) and the region measured using both neutrinos andantineutrinos under the assumption they have the same parameters(black line)
20
25
30
20 25 30
|Δm
2| (10
minus3eV
2)
|Δm2| (10minus3eV2)
68 CL|Δm2| = |Δm2|
MINOS 120583 disappearance1071 times 1020 POT 120583 mode336 times 1020 POT mode3788kt-yr atmospheric
90 CLBest fit
120583
Figure 14 A comparison of the measured limits on the masssplittings of neutrinos and antineutrinos
the Earthrsquos crust Assuming a normal mass hierarchy 120575 = 0and 120579
23lt 1205874 MINOS measures 2sin2(2120579
13)sin2(120579
23) =
0051+0038
minus0030 Assuming an inverted mass hierarchy 120575 = 0
and 12057923
lt 1205874 MINOS measures 2sin2(212057913)sin2(120579
23) =
0093+0054
minus0049 This measurement is consistent with the results
from reactor neutrino searches [72ndash74] and the T2K experi-ment [75]
This MINOS measurement is the first ever search for ]119890
appearance in a long-baseline ]120583beam and the first search
Advances in High Energy Physics 11
Reconstructed energy (GeV)0 6 8
Frac
tion
of ev
ents
0
01
02
03
04
Standard MC
MINOS
2 4
Near detector 2011
NC120583-CCe-CC
(a)
Horn-off MC
Reconstructed energy (GeV)0 6 8
Frac
tion
of ev
ents
0
01
02
03
04 MINOS
2 4
Near detector 2011
NC120583-CCe-CC
(b)
High energy MC
Reconstructed energy (GeV)0 6 8
Frac
tion
of ev
ents
0
01
02
03
04 MINOS
2 4
Near detector 2011
NC120583-CCe-CC
(c)
Figure 15 The contribution of the three components to the background in the ]119890appearance search as simulated in the ND (a) the regular
(low energy) beam data (b) with no current in the NuMI focusing horns (c) a high energy beam configuration
for ]119890and ]119890appearance with significant matter effects Both
of these effects provide some sensitivity to the neutrinomass hierarchy and CP violation when the MINOS data iscompared to the measurements made by reactor neutrinosearches [72ndash74] (we have calculated a limit of sin2(2120579
13) =
0098 plusmn 0013 from the reactor data at the time of analysis)The sensitivity of MINOS to the mass hierarchy and CPviolation is modest but this contributes to the first analysisof the type that will be used by all future long-baselineexperiments The resulting values of the likelihood by whichMINOS disfavours various values of these parameters areshown in Figure 18 [76]
6 Search for Sterile Neutrino Mixing UsingNeutral-Current Interactions
The energy spectrum of NC interactions in the FD should beunchanged by standard neutrino oscillationThe existence ofone or more sterile neutrino flavours ]
119904 could cause a deficit
in the observed NC interaction rate As with all the MINOSoscillation analyses the energy spectrum of NC interactionsobserved in the ND (which was shown in Figure 8) is usedto predict the spectrum expected at the FD [77] The FDexpectation is shown in Figure 19 with the dashed blue linetaking into account ]
119890appearance corresponding to 120579
13=
115∘ (at the limit set by CHOOZ [78] and a little above
the current accepted value [29 72ndash75] this analysis usesonly the first 707 times 10
20 protons on target of data andwas performed before the recent positive measurements ofa nonzero 120579
13) The data are also shown in the figure and
are in good agreement with the expectation confirming thestandard model of neutrino oscillation This agreement canbe quantified using a test statistic 119877
119877 =119873data minus 119861CC
119878NC (7)
where 119873data is the number of events observed 119861CC is thepredicted background of CC interactions and 119878NC is the
predicted number of NC interactions A value of 119877 = 101 plusmn
006(stat) plusmn 005(syst) is obtained (over the full energy range0ndash120GeV) which is in good agreement with the expectationof 119877 = 1 in the case of no mixing with sterile neutrinos
The data are analysed with a model that assumes a singlesterile neutrino flavour mixing through the addition of afourth neutrino mass state119898
4≫ 1198983 This introduces a mass
splitting Δ119898243
with magnitude O(1 eV2) such that no oscil-lation-induced change to the event rate is observed at theND and the oscillatory energy dependence of the induceddepletion at the FD is so rapid that an overall uniform deple-tion is observed once the energy resolution of the detectors isaccounted forThismodel introduces three additionalmixingangles 120579
14 12057924 and 120579
34 MINOS is insensitive to 120579
14but sets
limits of 12057924= (00
+5
minus00)∘ and 120579
34= (00
+25
minus00)∘ These limits are
evaluated assuming 12057913at the CHOOZ limit
The limit on the coupling of sterile to active neutrinos canbe quantified by defining 119891
119904 the fraction of disappearing ]
120583
which have oscillated into ]119904
119891119904=
119875]120583rarr ]119904
1 minus 119875]120583rarr ]120583
(8)
For the model used in which 1198984≫ 119898
3 119891119904is evaluated
at 14 GeV the energy of maximal ]120583disappearance To
determine the limit on 119891119904 a large number of test values
are chosen of the mixing angles 12057924 12057934 and 120579
23 from
Gaussian distributions according to the measured values and1120590 uncertainties given above (with 120579
23constrained from the
measurements with CC ]120583interactions) 119891
119904is calculated for
each case and the value of 119891119904that is larger than 90 of the
test cases represents the limit MINOS limits 119891119904lt 040 at the
90 confidence level
7 The Future MINOS+
The MINOS experiment has made some very importantcontributions to our understanding of neutrino oscillation
12 Advances in High Energy Physics
Reconstructed energy (GeV)
Reconstructed energy (GeV)
Even
ts
30
0
10
20
Even
ts
30
0
10
20
Even
ts
30
0
10
20
2 4 6 8
2 4 6 8
Reconstructed energy (GeV)2 4 6 8
06 lt 120572LEM lt 07
MINOS far detector data
07 lt 120572LEM lt 08
120572LEM gt 08
mode
mode
mode
e CC signal
e CC signalBackgroundData
(a)
Even
ts
Reconstructed energy (GeV)2 4 6 8
Reconstructed energy (GeV)2 4 6 8
Reconstructed energy (GeV)2 4 6 8
06 lt 120572LEM lt 07
MINOS far detector data
Merged for fit
07 lt 120572LEM lt 08
120572LEM gt 08
mode
mode
mode
8
6
4
2
0
Even
ts
8
6
4
2
0
Even
ts
8
6
4
2
0
e CC signal
e CC signalBackgroundData
5ndash8GeV bins
(b)
Figure 16 The CC ]119890(a) and ]
119890(b) candidate events selected in the FD compared to the expectation without any ]
119890appearance (red) and
with the best fit for 12057913(purple) The events are divided into bins of the library event matching discriminant variable
Advances in High Energy Physics 13
20
15
10
05
000 01 02 03 04
2sin2(212057913)sin212057923
Δm2 gt 0
sin
120575(120587)
(a)
20
15
10
05
000 01 02 03 04
2sin2(212057913)sin212057923
MINOS best fit 12057923 lt 1205874
MINOS best fit 12057923 gt 1205874
Δm2 lt 0
MINOS
106 times 1020 POT -mode33 times 1020 POT -mode
68 CL 12057923 lt 1205874
90 CL 12057923 lt 1205874
120575(120587)
(b)
Figure 17 The allowed regions for 2sin2(212057913)sin2(120579
23)
120575(120587)
Δm2 gt 0 12057923 gt 1205874
Δm2 gt 0 12057923 lt 1205874
Δm2 lt 0 12057923 gt 1205874Δm2 lt 0 12057923 lt 1205874
3
2
1
00 1 1505 2
MINOS
90 CL
68 CL
minus2Δ
(L)
ln
Figure 18 The values of likelihood 119871 by which various values oftheCP violating parameter 120575 the mass hierarchy and the octant of12057923are disfavouredThis analysis uses MINOS data and information
from reactor neutrino measurements of 12057913[72ndash74]
physics and has finished taking data with the low energybeam for which it was designed However the experimentwill continue taking data and producing new results for thenext few years as MINOS+ [79] The NuMI beam is being
20
2018161410 12
Far detector data
Even
ts (G
eV)
00 2 4 6 8
40
60
80
100
120
140
12057913 = 0∘
12057913 = 115∘ 120575 = 120587 Δm232 gt 0
120583 CC background|Δm2
32| = 232 times 10minus3eV2
Ereco (GeV)
sin2212057923 = 1
Figure 19 The black dots show the energy spectrum of NCinteractions observed in the far detector The red lines show theexpectation in the case of no sterile neutrinos and 120579
13= 0 the blue
dashed line shows the same expectation with 12057913= 115
∘
upgraded to a higher energy and intensity for the NO]Aexperiment the far detector of which will sit 14 mrad offaxisNO]A will receive a narrow-band beam peaking at around2GeV which is ideal for searching for ]
119890appearance since
the background seen in MINOS from NC interactions ofhigh energy neutrinos will be heavily reduced Figure 20shows that the MINOS FD will see an intense ]
120583beam
14 Advances in High Energy Physics
1000
500
00 5 10 15 20
E (GeV)
MINOS+NOAMINOS
Preliminary
Simulated beam54 kton 6 times 1020 POT
120583CC
even
ts (G
eV)
Figure 20 The ]120583energy spectrum that will be observed by the
MINOS+ FD compared to the spectra observed by MINOS andNO]A
peaking at around 7GeV In this configuration MINOS+ willobserve around 4000 CC ]
120583interactions in the FD each
year unprecedented statistics for a long-baseline oscillationexperimentThis will offer a unique high precision test of thethree-flavour oscillation paradigm
MINOS+ will be able to make a very sensitive searchfor the sterile neutrinos suggested by the LSND [80] andMiniBooNE [81 82] data and by some interpretations ofreactor neutrino data [83] This search will cover more thanthree orders of magnitude in the mass splitting between thesterile and active neutrinos The signal that MINOS+ willsearch for is illustrated in Figure 21 Figure 21(a) illustratesthe increase in statistical precision thatMINOS+will provideon the ratio of the observed CC ]
120583interaction rate to
that expected without oscillations Figure 21(b) shows howthis ratio is modified if a sterile neutrino exists and mixeswith the active neutrinos an additional deficit of muonneutrino interactions occurs in the higher energy region ofthe spectrum In the model assumed here which introducesa single sterile neutrino state three new mixing angles areintroduced 120579
14 12057924 and 120579
34 An additional mass splitting
Δ1198982
43is also introduced The position in energy of the
additional deficit is governed by the value of the new masssplittingThemagnitude of the additional deficit in the CC ]
120583
interaction rate is governed primarily by the size of 12057924 this is
in comparison to short-baseline searches for ]119890disappearance
from reactors which are governed by 12057914and searches for ]
119890
appearance in ]120583beamswhich are governed by a combination
of 12057914
and 12057924 A detailed explanation of the global effort to
search for sterile neutrinos can be found in [84]The sensitivity of the MINOS+ experiment when com-
bined with the Bugey reactor neutrino data [85] is shown in
MINOS+ simulation
MINOS 1071 times 1021 POT06 times 1021 POT12 times 1021 POT18 times 1021 POT
120583su
rviv
al p
roba
bilit
y
Neutrino energy (GeV)0 5 10 15
15
1
05
0
(a)
P(
120583rarr
120583)
No sterile neutrinosΔm2
43 = 2 times 10minus2eV2 sin2(212057924) = 02
0 5 10 15 20
1
0
18
06
04
02
Neutrino energy (GeV)
(b)
Figure 21 (a) The black points show the ratio of the observed ]120583
energy spectrum to the expectation in the case of no oscillation inthe neutrino-dominated beam of MINOS The blue region showsthe statistical precision expected from MINOS+ (b) The black lineshows the muon neutrino survival probability in the case of nosterile neutrinos the red line shows how the probability would bemodified by the addition of mixing with a sterile neutrino
Figure 22 MINOS+ has the potential to rule out much of theLSND allowed region MINOS+ will begin taking data in thelate summer of 2013 and will continue taking data for at leasttwo years (Figure 22 assumes two years of data taking with aneutrino-dominated beam)
8 Conclusion
The MINOS experiment was conceived at a time when neu-trino oscillation had only recently been confirmed as thesolution to the problem of neutrino flavour change It has
Advances in High Energy Physics 15
Δm
2
10minus210minus2
10minus1
10minus1
10minus310minus4 1
1
10
102
LSND 90 CLLSND 99 CLKarmen2 90 CLBugey 90 CLlowast
MiniBooNE 90 CLMiniBooNE 99 CLMINOS+ and Bugeycombination 90 CL
sin22120579120583e
lowastGLoBES 2012 fit with new reactor fluxescourtesy of P Huber
Figure 22 The sensitivity of MINOS+ to the existence of sterileneutrinos when combined with data from the Bugey [85] reactorneutrino experiment Δ1198982 is the splitting between the three knownneutrino mass states and a new fourth state 120579
120583119890is the mixing angle
governing ]120583rarr ]119890transitions when a fourth sterile neutrino state
is introduced into the PMNSmixingmatrixThis figure assumes twoyears of MINOS+ running with a neutrino-dominated beam
played a hugely influential role in bringing neutrino oscilla-tion physics into an era of precision measurement MINOSrsquosmeasurement of the largest neutrino mass splitting is themost precise in the world MINOS has made the first directprecision measurement of the corresponding antineutrinoparameters a measurement that promises to remain theworldrsquos most precise for many years And MINOS has playeda role in the discovery of a nonzero value for 120579
13
Now that the value of 12057913is known the neutrino physics
community can move on to determine the neutrino masshierarchy and to search for CP violation in the neutrinosector MINOS has pioneered a number of techniques thatwill be used by future experiments The two-detector setupall important in reducing the impact of systematic uncer-tainties is the design of choice for any new experiment andMINOS has demonstrated methods of using a near detectorto determine the expectation at a far detector MINOS hasperformed the first search for ]
119890appearance in a ]
120583beam
and the first search for ]119890and ]119890appearance with significant
matter effects demonstrating the analysis techniques that willbe used to determine the mass hierarchy and CP violationparameter
In the second half of 2013 MINOS will begin taking dataas the MINOS+ experiment which will make ever more pre-cise tests of the three-flavour neutrino oscillation paradigmand set world-leading limits on the existence of sterileneutrinos This is an exciting future for an experiment thatwith a decade of data taking so far has already created alasting legacy for itself in our understanding of the neutrino
A comparison of themeasured neutrino and antineutrinomass splittings is shown in Figure 14 the difference betweenthe two is constrained to |Δ119898
2| minus |Δ119898
2| = (012
+024
minus026) times
10minus3 eV2
Acknowledgment
The work of the MINOS and MINOS+ collaborations issupported by the US DoE the UK STFC the US NSF theState and University of Minnesota the University of Athensin Greece and Brazilrsquos FAPESP and CNPq The authors aregrateful to the Minnesota Department of Natural Resourcesthe crew of the Soudan Underground Laboratory and thepersonnel of Fermilab for their vital contributions
References
[1] S Wojcicki ldquoLong baseline neutrino oscillation programe inthe United Statesrdquo Nuclear Physics B vol 77 no 1ndash3 pp 182ndash186 1999 Proceedings of the 18th International Conference onNeutrino Physics and Astrophysics (Neutrino rsquo98) TakayamaJapan June 1998
[2] R Davis Jr D S Harmer and K C Hoffman ldquoSearch forneutrinos from the sunrdquo Physical Review Letters vol 20 no 21pp 1205ndash1209 1968
[3] A I Abazov O L Anosov E L Faizov et al ldquoSearch forneutrinos from sun using the reactionGa-71 (electron-neutrinoe-) Ge-71rdquo Physical Review Letters vol 67 pp 3332ndash3335 1991
[4] P Anselmann W Hampel G Heusser et al ldquoSolar neutrinosobserved by GALLEX at gran sassordquo Physics Letters B vol 285no 4 pp 376ndash389 1992
[5] M Aglietta G Battistoni E Bellotti et al ldquoExperimentalstudy of atmospheric neutrino flux in the NUSEX experimentrdquoEurophysics Letters vol 8 no 7 article 611 1989
[6] K S Hirata ldquoObservation of a small atmospheric V120583V119890ratio in
Kamiokanderdquo Physics Letters B vol 280 no 1-2 pp 146ndash1521992
[7] R Becker-Szendy C B Bratton D Casper et al ldquoElectron-and muon-neutrino content of the atmospheric fluxrdquo PhysicalReview D vol 46 pp 3720ndash3724 1992
[8] K Daum W Rhode P Bareyre et al ldquoDetermination ofthe atmospheric neutrino spectra with the frejus detectorrdquoZeitschrift fur Physik C vol 66 no 3 pp 417ndash428 1995
[9] S Ahlen M Ambrosio R Antolini and G Auriemma ldquoAtmo-spheric neutrino flux measurement using upgoing muonsrdquoPhysics Letters B vol 357 no 3 pp 481ndash486 1995
[10] WMAllison G J Alner D S Ayres et al ldquoMeasurement of theatmospheric neutrino flavour composition in Soudan 2rdquoPhysicsLetters B vol 391 no 3-4 pp 491ndash500 1997
16 Advances in High Energy Physics
[11] Y Fukuda T Hayakawa E Ichihara et al ldquoEvidence foroscillation of atmospheric neutrinosrdquo Physical Review Lettersvol 81 no 8 pp 1562ndash1567 1998
[12] Q R Ahmad R C Allen T C Andersen et al ldquoMeasurementof charged current interactions produced by solar neutrinos atthe sudbury neutrino observatoryrdquo Physical Review Letters vol87 Article ID 071301 2001
[13] Q R Ahmad R C Allen T C Andersen et al ldquoDirect evidencefor neutrino flavor transformation from neutral-current inter-actions in the sudbury neutrino observatoryrdquo Physical ReviewLetters vol 89 Article ID 011301 6 pages 2002
[14] B Pontecorvo ldquoInverse beta processes and nonconservation oflepton chargerdquo Journal of Experimental and Theoretical Physicsvol 34 pp 172ndash173 1958
[15] V N Gribov and B Pontecorvo ldquoNeutrino astronomy andlepton chargerdquo Physics Letters B vol 28 pp 493ndash496 1969
[16] Z Maki M Nakagawa and S Sakata ldquoRemarks on the unifiedmodel of elementary particlesrdquo Progress of Theoretical Physicsvol 28 no 5 pp 870ndash880 1962
[17] P Adamson C Andreopoulos D J Auty et al ldquoFirst directobservation of muon antineutrino disappearancerdquo PhysicalReview Letters vol 107 no 2 Article ID 021801 2011
[18] P Adamson D J Auty D S Ayres et al ldquoSearch for thedisappearance of muon antineutrinos in the NuMI neutrinobeamrdquo Physical Review D vol 84 no 7 Article ID 071103 6pages 2011
[19] P Adamson D S Ayres C Backhouse et al ldquoImprovedmeasurement of muon antineutrino disappearance inMINOSrdquoPhysical Review Letters vol 108 no 19 Article ID 191801 5pages 2012
[20] P Adamson I Anghel C Backhouse et al ldquoMeasurementof Neutrino and Antineutrino Oscillations Using Beam andAtmospheric Data in MINOSrdquo Physical Review Letters vol 110no 25 Article ID 251801 6 pages 2013
[21] K Anderson B Bernstein D Boehnlein et al ldquoThe NuMIFacility Technical Design Reportrdquo FERMILAB-DESIGN-1998-01 1998
[22] D G Michael P Adamson T Alexopoulos et al ldquoObservationof muon neutrino disappearance with the MINOS detectors inthe NuMI neutrino beamrdquo Physical Review Letters vol 97 no19 Article ID 191801 6 pages 2006
[23] P Adamson C Andreopoulos K E Arms et al ldquoStudy ofmuon neutrino disappearance using the fermilab main injectorneutrino beamrdquo Physical Review D vol 77 no 7 Article ID072002 34 pages 2008
[24] P Adamson C Andreopoulos K E Arms et al ldquoMeasurementof neutrino oscillations with theMINOS detectors in the NuMIbeamrdquo Physical Review Letters vol 101 no 13 Article ID 1318025 pages 2008
[25] P Adamson C Andreopoulos R Armstrong et al ldquoMea-surement of the neutrino mass splitting and flavor mixing byMINOSrdquo Physical Review Letters vol 106 no 18 Article ID181801 6 pages 2011
[26] P Adamson C Andreopoulos K E Arms et al ldquoSearch formuon-neutrino to electron-neutrino transitions in MINOSrdquoPhysical Review Letters vol 103 no 26 Article ID 261802 5pages 2009
[27] PAdamsonCAndreopoulosD J Auty et al ldquoNew constraintsonmuon-neutrino to electron-neutrino transitions inMINOSrdquoPhysical ReviewD vol 82 no 5 Article ID 051102 6 pages 2010
[28] P Adamson D J Auty D S Ayres et al ldquoImproved search formuon-neutrino to electron-neutrino oscillations in MINOSrdquoPhysical Review Letters vol 107 no 18 Article ID 181802 6pages 2011
[29] P Adamson I Anghel C Backhouse et al ldquoElectron neutrinoand antineutrino appearance in the full MINOS data samplerdquoPhysical Review Letters vol 110 no 17 Article ID 171801 6 pages2013
[30] P Adamson C Andreopoulos K E Arms et al ldquoSearch foractive neutrino disappearance using neutral-current interac-tions in theMINOS long-baseline experimentrdquo Physical ReviewLetters vol 101 no 22 Article ID 221804 5 pages 2008
[31] P Adamson C Andreopoulos D J Auty et al ldquoSearch for ster-ile neutrino mixing in the MINOS long-baseline experimentrdquoPhysical Review D vol 81 no 5 Article ID 052004 18 pages2010
[32] P Adamson D J Auty D S Ayres et al ldquoActive to sterileneutrino mixing limits from neutral-current interactions inMINOSrdquo Physical Review Letters vol 107 no 1 Article ID011802 5 pages 2011
[33] Z Pavlovic Observation of disappearance of muon neutrinos inthe NuMI beam [PhD thesis] University of Texas at AustinAustin Tex USA 2008
[34] F Ballarini G Battistoni M Campanella et al ldquoThe FLUKAcode an overviewrdquo Journal of Physics vol 41 article 151 2006
[35] S Agostinelli J Allison K Amako et al ldquoGEANT4mdasha sim-ulation toolkitrdquo Nuclear Instruments and Methods in PhysicsResearch A vol 506 no 3 pp 250ndash303 2003
[36] G Battistoni F Cerutti A Fasso et al ldquoThe FLUKA codedescription and benchmarkingrdquo in Proceedings of the HadronicShower Simulation Workshop vol 896 of AIP Conference Pro-ceedings pp 31ndash49 Batavia Ill USA September 2006
[37] D G Michaele P Adamson T Alexopoulos et al ldquoThe mag-netized steel and scintillator calorimeters of the MINOS exper-imentrdquoNuclear Instruments and Methods in Physics Research Avol 596 no 2 pp 190ndash228 2008
[38] I E Stockdale A Bodek F Borcherding N Giokaris et alldquoLimits on muon-neutrino oscillations in the mass range 30 lt9987791198982lt 1000 eV2c4 rdquo Physical Review Letters vol 52 no 16 pp
1384ndash1388 1984[39] F Dydak G J Feldman C Guyot et al ldquoA search for V
120583
oscillations in the9987791198982 range 03ndash90 eV2 rdquo Physics Letters B vol134 no 3-4 pp 281ndash286 1984
[40] F Bergsma J Dorenbosch M Jonker et al ldquoA searchfor oscillations of muon neutrinos in an experiment withLEcong07 kmGeVrdquo Physics Letters B vol 142 no 1-2 pp 103ndash1101984
[41] M H Ahn E Aliu S Andringa et al ldquoMeasurement ofneutrino oscillation by the K2K experimentrdquo Physical ReviewD vol 74 no 7 Article ID 072003 39 pages 2006
[42] P Adamson T Alexopoulos W W M Allison et al ldquoFirstobservations of separated atmospheric V
120583and ]
120583events in the
MINOS detectorrdquo Physical Review D vol 73 no 7 Article ID072002 2006
[43] P Adamson C Andreopoulos K E Arms et al ldquoCharge-separated atmospheric neutrino-inducedmuons in theMINOSfar detectorrdquo Physical ReviewD vol 75 no 9 Article ID 09200314 pages 2007
[44] P Adamson C Backhouse G Barr et al ldquoMeasurements ofatmospheric neutrinos and antineutrinos in the MINOS fardetectorrdquo Physical Review D vol 86 no 5 Article ID 05200720 pages 2012
Advances in High Energy Physics 17
[45] M A Kordosky Hadronic interactions in the MINOS detectors[PhD thesis] University of Texas at Austin Austin Tex USA2004
[46] P L Vahle Electromagnetic interactions in the MINOS detectors[PhD thesis] University of Texas at Austin Austin Tex USA2004
[47] C Backhouse Measuring neutrino oscillation parameters using]120583disappearance inMINOS [PhD thesis] University of Oxford
Oxford UK 2011[48] T M Cover and P E Hart ldquoNearest neighbor pattern classifi-
cationrdquo IEEE Transactions on Information Theory vol 13 no 1pp 21ndash27 1967
[49] R Ospanov A measurement of muon neutrino disappearancewith the MINOS detectors and NuMI beam [PhD thesis]University of Texas at Austin Austin Tex USA 2008
[50] J S Marshall A study of muon neutrino disappearance with theMINOS detectors and the NuMI neutrino beam [PhD thesis]University of Cambridge Cambridge UK 2008
[51] J P OchoaA search formuon neutrino to electron neutrino oscil-lations in the MINOS Experiment [PhD thesis] The CaliforniaInstitute of Technology Pasadena Calif USA 2009
[52] R TonerMeasuring 12057913via muon neutrino to electron neutrino
oscillations in the MINOS experiment [PhD thesis] Universityof Cambridge Cambridge UK 2011
[53] A Holin Electron neutrino appearance in the MINOS experi-ment [PhD thesis] University College London London UK2010
[54] J Boehm Measurement of electron neutrino appearance withthe MINOS experiment [PhD thesis] Harvard UniversityCambridge Mass USA 2009
[55] G Tinti Sterile neutrino oscillations in MINOS and hadronproduction in pC collisions [PhD thesis] University of OxfordOxford UK 2010
[56] J J EvansMeasuring antineutrino oscillations with the MINOSexperiment [PhD thesis] University of Oxford Oxford UK2008
[57] S J ColemanAmeasurement of neutrino oscillations withmuonneutrinos in the MINOS experiment [PhD thesis] College ofWilliam ampMary Williamsburg Va USA 2011
[58] J S Mitchell Measuring ]120583disappearance with the MINOS
experiment [PhD thesis] University of Cambridge CambridgeUK 2011
[59] A McGowan Observation of deficit in NuMI neutrino-inducedrock and non-fiducial muons in MINOS far detector andmeasurement of neutrino oscillation parameters [PhD thesis]University of Minnesota Minneapolis Minn USA 2007
[60] M StraitMeasurement of neutrino oscillation parameters usinganti-fiducial charged current events in MINOS [PhD thesis]University of Minnesota Minneapolis Minn USA 2010
[61] Y Itow ldquoAtmospheric neutrinosmdashresults from running exper-imentsrdquo in Proceedings of the 25th International Conference onNeutrino Physics and Astrophysics (Neutrino rsquo12) Kyoto JapanJune 2012
[62] K Abe N Abgrall Y Ajima et al ldquoFirst muon-neutrinodisappearance study with an off-axis beamrdquo Physical Review Dvol 85 no 3 Article ID 031103 8 pages 2012
[63] K Nakamura ldquoReview of particle physicsrdquo Journal of Physics Gvol 37 Article ID 075021 2010
[64] L Wolfenstein ldquoNeutrino oscillations in matterrdquo PhysicalReview D vol 17 no 9 pp 2369ndash2374 1978
[65] J W F Valle ldquoResonant oscillations of massless neutrinos inmatterrdquo Physics Letters B vol 199 no 3 pp 432ndash436 1987
[66] M C Gonzalez-Garcia M M Guzzo P I Krastev et alldquoAtmospheric neutrino observations and flavor changing inter-actionsrdquo Physical Review Letters vol 82 no 16 pp 3202ndash32051999
[67] A Friedland C Lunardini and M Maltoni ldquoAtmosphericneutrinos as probes of neutrino-matter interactionsrdquo PhysicalReview D vol 70 no 11 Article ID 111301 2004
[68] Z IsvanAntineutrino oscillations and a Search for non-standardInteractions with the MINOS [PhD thesis] University of Pitts-burgh Pittsburgh Pa USA 2012
[69] W A Mann D Cherdack W Musial and T Kafka ldquoApparentmultiple 998779119898
32
2 in ]120583and V
120583survival oscillations from nonstan-
dard interactionmatter effectrdquo Physical Review D vol 82 no 11Article ID 113010 8 pages 2010
[70] J Kopp P A N Machado and S J Parke ldquoInterpretation ofMINOS data in terms of nonstandard neutrino interactionsrdquoPhysical Review D vol 82 no 11 Article ID 113002 12 pages2010
[71] J A B Coelho Investigacao de mecanismos alternativos aoscilacao de neutrinos no experimentos MINOS [PhD thesis]Universidade Estadual de Campinas Sao Paulo Brazil 2012
[72] F P An Q An J Z Bai A B Balantekin et al ldquoImprovedmeasurement of electron antineutrino disappearance at DayaBayrdquo Chinese Physics C vol 37 Article ID 011001 21 pages 2013
[73] J K Ahn S Chebotaryov J H Choi et al ldquoObservationof reactor electron antineutrinos disappearance in the RENOexperimentrdquo Physical Review Letters vol 108 Article ID 1918026 pages 2012
[74] Y Abe C Aberle J C dos Anjos et al ldquoReactor electronantineutrino disappearance in the Double Chooz experimentrdquoPhysical Review D vol 86 Article ID 052008 2012
[75] K Abe N Abgrall H Aihara et al ldquoEvidence of electronneutrino appearance in a muon neutrino beamrdquo PhysicalReview D vol 88 no 3 Article ID 032002 41 pages 2013
[76] A Schreckenberger Electron neutrino and antineutrino appear-ance in the MINOS detector [PhD thesis] University of Min-nesota Minneapolis Minn USA 2013
[77] D J Koskinen MINOS sterile neutrino search [PhD thesis]University College London London UK 2009
[78] M Apollonio A Baldini C Bemporad et al ldquoSearch forneutrino oscillations on a long base-line at the CHOOZ nuclearpower stationrdquoTheEuropean Physical Journal C vol 27 pp 331ndash374 2003
[79] G Tzanankos M Bishai M Diwan et alMINOS+ a proposalto FNAL to run MINOS with the medium energy NuMI beam[PhD thesis] University of Athens Athens Greece 2011
[80] A Aguilar L B Auerbach R L Burman et al ldquoEvidence forneutrino oscillations from the observation of ]
119890e appearance
in a ]120583beamrdquo Physical Review D vol 64 Article ID 112007 22
pages 2001[81] A A Aguilar-Arevalo C E Anderson S J Brice et al ldquoSearch
for electron antineutrino appearance at the Δ119898 sim 1 eV2 ScalerdquoPhysical Review Letters vol 103 no 11 Article ID 111801 2009
[82] A A Aguilar-Arevalo C E Anderson A O Bazarko et alldquoImproved search for V
120583rarr V119890oscillations in the MiniBooNE
experimentrdquo Physical Review Letter vol 110 no 10 Article ID161801 2013
[83] GMentionM Fechner T Lasserre et al ldquoReactor antineutrinoanomalyrdquo Physical Review D vol 83 Article ID 073006 20pages 2011
18 Advances in High Energy Physics
[84] KNAbazajianMAAcero S KAgarwalla et al ldquoLight sterileneutrinos a white paperrdquo httparxivorgabs12045379
[85] B Achkar R Aleksan M Avenier et al ldquoSearch for neutrinooscillations at 15 40 and 95meters from a nuclear power reactorat Bugeyrdquo Nuclear Physics B vol 434 no 3 pp 503ndash532 1995
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
High Energy PhysicsAdvances in
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
FluidsJournal of
Atomic and Molecular Physics
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in Condensed Matter Physics
OpticsInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
AstronomyAdvances in
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Superconductivity
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Statistical MechanicsInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
GravityJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
AstrophysicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Physics Research International
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Solid State PhysicsJournal of
Computational Methods in Physics
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Soft MatterJournal of
Hindawi Publishing Corporationhttpwwwhindawicom
AerodynamicsJournal of
Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
PhotonicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Biophysics
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
ThermodynamicsJournal of
10 Advances in High Energy PhysicsRa
tio to
no
osci
llatio
ns
05
1
15
2
25
0 10 15 20 30 50
MINOS far detector data
5Reconstructed 120583 energy (GeV)
1071 times 1020 POT
Prediction Δm2 = 241 times 10minus3eV2
Low energy beam 120583-mode
Figure 11 The ratio of the observed ]120583energy spectrum to the
expectation in the case of no oscillation in the neutrino-dominatedbeam The black points show the data the blue line shows the bestfit to the data
075 080 085 090 095 10015
20
25
30
35
40
90 CL68 CL
90 CL
sin2(2120579)
|Δm
2|(10minus3eV
2)
MINOS 3788 kt-yr atmospheric
336 times 1020 POT 120583 modeSuper-K zenith anglelowast
Super-K LElowast
T2Klowastlowast
lowastNeutrino 2012lowastlowastPRD 85 031103(R) (2012)
1071 times 1020 POT 120583 mode
Figure 12 The allowed regions for the atmospheric oscillationparameters |Δ1198982| and sin2(2120579) assuming identical neutrino andantineutrino oscillation parametersTheMINOS result is comparedto measurements from Super-Kamiokande [61] and T2K [62]
The data are fit to extract a measurement of 12057913 The
resulting measurement is shown in Figure 17 The measuredvalue of 120579
13depends on the CP violating phase 120575 which
directly affects the ]119890and ]
119890appearance probabilities and
themass hierarchy which affects the appearance probabilitiesthrough the interactions of the neutrinos with the matter in
MINOS 120583 disappearance1071 times 1020 POT 120583 mode336 times 1020 POT mode3788kt-yr atmospheric
90 CL120583120583120583 + 120583
120583120583120583 + 120583
Best fit
sin2(2120579) or sin2(2120579)
(|Δm
2|
or Δ
m2|)
(10minus3eV
2)
075 080 085 090 095 100
20
25
30
35
120583
|Figure 13 The allowed region for antineutrino oscillation param-eters (blue line) compared to the region measured with neutrinosalone (red line) and the region measured using both neutrinos andantineutrinos under the assumption they have the same parameters(black line)
20
25
30
20 25 30
|Δm
2| (10
minus3eV
2)
|Δm2| (10minus3eV2)
68 CL|Δm2| = |Δm2|
MINOS 120583 disappearance1071 times 1020 POT 120583 mode336 times 1020 POT mode3788kt-yr atmospheric
90 CLBest fit
120583
Figure 14 A comparison of the measured limits on the masssplittings of neutrinos and antineutrinos
the Earthrsquos crust Assuming a normal mass hierarchy 120575 = 0and 120579
23lt 1205874 MINOS measures 2sin2(2120579
13)sin2(120579
23) =
0051+0038
minus0030 Assuming an inverted mass hierarchy 120575 = 0
and 12057923
lt 1205874 MINOS measures 2sin2(212057913)sin2(120579
23) =
0093+0054
minus0049 This measurement is consistent with the results
from reactor neutrino searches [72ndash74] and the T2K experi-ment [75]
This MINOS measurement is the first ever search for ]119890
appearance in a long-baseline ]120583beam and the first search
Advances in High Energy Physics 11
Reconstructed energy (GeV)0 6 8
Frac
tion
of ev
ents
0
01
02
03
04
Standard MC
MINOS
2 4
Near detector 2011
NC120583-CCe-CC
(a)
Horn-off MC
Reconstructed energy (GeV)0 6 8
Frac
tion
of ev
ents
0
01
02
03
04 MINOS
2 4
Near detector 2011
NC120583-CCe-CC
(b)
High energy MC
Reconstructed energy (GeV)0 6 8
Frac
tion
of ev
ents
0
01
02
03
04 MINOS
2 4
Near detector 2011
NC120583-CCe-CC
(c)
Figure 15 The contribution of the three components to the background in the ]119890appearance search as simulated in the ND (a) the regular
(low energy) beam data (b) with no current in the NuMI focusing horns (c) a high energy beam configuration
for ]119890and ]119890appearance with significant matter effects Both
of these effects provide some sensitivity to the neutrinomass hierarchy and CP violation when the MINOS data iscompared to the measurements made by reactor neutrinosearches [72ndash74] (we have calculated a limit of sin2(2120579
13) =
0098 plusmn 0013 from the reactor data at the time of analysis)The sensitivity of MINOS to the mass hierarchy and CPviolation is modest but this contributes to the first analysisof the type that will be used by all future long-baselineexperiments The resulting values of the likelihood by whichMINOS disfavours various values of these parameters areshown in Figure 18 [76]
6 Search for Sterile Neutrino Mixing UsingNeutral-Current Interactions
The energy spectrum of NC interactions in the FD should beunchanged by standard neutrino oscillationThe existence ofone or more sterile neutrino flavours ]
119904 could cause a deficit
in the observed NC interaction rate As with all the MINOSoscillation analyses the energy spectrum of NC interactionsobserved in the ND (which was shown in Figure 8) is usedto predict the spectrum expected at the FD [77] The FDexpectation is shown in Figure 19 with the dashed blue linetaking into account ]
119890appearance corresponding to 120579
13=
115∘ (at the limit set by CHOOZ [78] and a little above
the current accepted value [29 72ndash75] this analysis usesonly the first 707 times 10
20 protons on target of data andwas performed before the recent positive measurements ofa nonzero 120579
13) The data are also shown in the figure and
are in good agreement with the expectation confirming thestandard model of neutrino oscillation This agreement canbe quantified using a test statistic 119877
119877 =119873data minus 119861CC
119878NC (7)
where 119873data is the number of events observed 119861CC is thepredicted background of CC interactions and 119878NC is the
predicted number of NC interactions A value of 119877 = 101 plusmn
006(stat) plusmn 005(syst) is obtained (over the full energy range0ndash120GeV) which is in good agreement with the expectationof 119877 = 1 in the case of no mixing with sterile neutrinos
The data are analysed with a model that assumes a singlesterile neutrino flavour mixing through the addition of afourth neutrino mass state119898
4≫ 1198983 This introduces a mass
splitting Δ119898243
with magnitude O(1 eV2) such that no oscil-lation-induced change to the event rate is observed at theND and the oscillatory energy dependence of the induceddepletion at the FD is so rapid that an overall uniform deple-tion is observed once the energy resolution of the detectors isaccounted forThismodel introduces three additionalmixingangles 120579
14 12057924 and 120579
34 MINOS is insensitive to 120579
14but sets
limits of 12057924= (00
+5
minus00)∘ and 120579
34= (00
+25
minus00)∘ These limits are
evaluated assuming 12057913at the CHOOZ limit
The limit on the coupling of sterile to active neutrinos canbe quantified by defining 119891
119904 the fraction of disappearing ]
120583
which have oscillated into ]119904
119891119904=
119875]120583rarr ]119904
1 minus 119875]120583rarr ]120583
(8)
For the model used in which 1198984≫ 119898
3 119891119904is evaluated
at 14 GeV the energy of maximal ]120583disappearance To
determine the limit on 119891119904 a large number of test values
are chosen of the mixing angles 12057924 12057934 and 120579
23 from
Gaussian distributions according to the measured values and1120590 uncertainties given above (with 120579
23constrained from the
measurements with CC ]120583interactions) 119891
119904is calculated for
each case and the value of 119891119904that is larger than 90 of the
test cases represents the limit MINOS limits 119891119904lt 040 at the
90 confidence level
7 The Future MINOS+
The MINOS experiment has made some very importantcontributions to our understanding of neutrino oscillation
12 Advances in High Energy Physics
Reconstructed energy (GeV)
Reconstructed energy (GeV)
Even
ts
30
0
10
20
Even
ts
30
0
10
20
Even
ts
30
0
10
20
2 4 6 8
2 4 6 8
Reconstructed energy (GeV)2 4 6 8
06 lt 120572LEM lt 07
MINOS far detector data
07 lt 120572LEM lt 08
120572LEM gt 08
mode
mode
mode
e CC signal
e CC signalBackgroundData
(a)
Even
ts
Reconstructed energy (GeV)2 4 6 8
Reconstructed energy (GeV)2 4 6 8
Reconstructed energy (GeV)2 4 6 8
06 lt 120572LEM lt 07
MINOS far detector data
Merged for fit
07 lt 120572LEM lt 08
120572LEM gt 08
mode
mode
mode
8
6
4
2
0
Even
ts
8
6
4
2
0
Even
ts
8
6
4
2
0
e CC signal
e CC signalBackgroundData
5ndash8GeV bins
(b)
Figure 16 The CC ]119890(a) and ]
119890(b) candidate events selected in the FD compared to the expectation without any ]
119890appearance (red) and
with the best fit for 12057913(purple) The events are divided into bins of the library event matching discriminant variable
Advances in High Energy Physics 13
20
15
10
05
000 01 02 03 04
2sin2(212057913)sin212057923
Δm2 gt 0
sin
120575(120587)
(a)
20
15
10
05
000 01 02 03 04
2sin2(212057913)sin212057923
MINOS best fit 12057923 lt 1205874
MINOS best fit 12057923 gt 1205874
Δm2 lt 0
MINOS
106 times 1020 POT -mode33 times 1020 POT -mode
68 CL 12057923 lt 1205874
90 CL 12057923 lt 1205874
120575(120587)
(b)
Figure 17 The allowed regions for 2sin2(212057913)sin2(120579
23)
120575(120587)
Δm2 gt 0 12057923 gt 1205874
Δm2 gt 0 12057923 lt 1205874
Δm2 lt 0 12057923 gt 1205874Δm2 lt 0 12057923 lt 1205874
3
2
1
00 1 1505 2
MINOS
90 CL
68 CL
minus2Δ
(L)
ln
Figure 18 The values of likelihood 119871 by which various values oftheCP violating parameter 120575 the mass hierarchy and the octant of12057923are disfavouredThis analysis uses MINOS data and information
from reactor neutrino measurements of 12057913[72ndash74]
physics and has finished taking data with the low energybeam for which it was designed However the experimentwill continue taking data and producing new results for thenext few years as MINOS+ [79] The NuMI beam is being
20
2018161410 12
Far detector data
Even
ts (G
eV)
00 2 4 6 8
40
60
80
100
120
140
12057913 = 0∘
12057913 = 115∘ 120575 = 120587 Δm232 gt 0
120583 CC background|Δm2
32| = 232 times 10minus3eV2
Ereco (GeV)
sin2212057923 = 1
Figure 19 The black dots show the energy spectrum of NCinteractions observed in the far detector The red lines show theexpectation in the case of no sterile neutrinos and 120579
13= 0 the blue
dashed line shows the same expectation with 12057913= 115
∘
upgraded to a higher energy and intensity for the NO]Aexperiment the far detector of which will sit 14 mrad offaxisNO]A will receive a narrow-band beam peaking at around2GeV which is ideal for searching for ]
119890appearance since
the background seen in MINOS from NC interactions ofhigh energy neutrinos will be heavily reduced Figure 20shows that the MINOS FD will see an intense ]
120583beam
14 Advances in High Energy Physics
1000
500
00 5 10 15 20
E (GeV)
MINOS+NOAMINOS
Preliminary
Simulated beam54 kton 6 times 1020 POT
120583CC
even
ts (G
eV)
Figure 20 The ]120583energy spectrum that will be observed by the
MINOS+ FD compared to the spectra observed by MINOS andNO]A
peaking at around 7GeV In this configuration MINOS+ willobserve around 4000 CC ]
120583interactions in the FD each
year unprecedented statistics for a long-baseline oscillationexperimentThis will offer a unique high precision test of thethree-flavour oscillation paradigm
MINOS+ will be able to make a very sensitive searchfor the sterile neutrinos suggested by the LSND [80] andMiniBooNE [81 82] data and by some interpretations ofreactor neutrino data [83] This search will cover more thanthree orders of magnitude in the mass splitting between thesterile and active neutrinos The signal that MINOS+ willsearch for is illustrated in Figure 21 Figure 21(a) illustratesthe increase in statistical precision thatMINOS+will provideon the ratio of the observed CC ]
120583interaction rate to
that expected without oscillations Figure 21(b) shows howthis ratio is modified if a sterile neutrino exists and mixeswith the active neutrinos an additional deficit of muonneutrino interactions occurs in the higher energy region ofthe spectrum In the model assumed here which introducesa single sterile neutrino state three new mixing angles areintroduced 120579
14 12057924 and 120579
34 An additional mass splitting
Δ1198982
43is also introduced The position in energy of the
additional deficit is governed by the value of the new masssplittingThemagnitude of the additional deficit in the CC ]
120583
interaction rate is governed primarily by the size of 12057924 this is
in comparison to short-baseline searches for ]119890disappearance
from reactors which are governed by 12057914and searches for ]
119890
appearance in ]120583beamswhich are governed by a combination
of 12057914
and 12057924 A detailed explanation of the global effort to
search for sterile neutrinos can be found in [84]The sensitivity of the MINOS+ experiment when com-
bined with the Bugey reactor neutrino data [85] is shown in
MINOS+ simulation
MINOS 1071 times 1021 POT06 times 1021 POT12 times 1021 POT18 times 1021 POT
120583su
rviv
al p
roba
bilit
y
Neutrino energy (GeV)0 5 10 15
15
1
05
0
(a)
P(
120583rarr
120583)
No sterile neutrinosΔm2
43 = 2 times 10minus2eV2 sin2(212057924) = 02
0 5 10 15 20
1
0
18
06
04
02
Neutrino energy (GeV)
(b)
Figure 21 (a) The black points show the ratio of the observed ]120583
energy spectrum to the expectation in the case of no oscillation inthe neutrino-dominated beam of MINOS The blue region showsthe statistical precision expected from MINOS+ (b) The black lineshows the muon neutrino survival probability in the case of nosterile neutrinos the red line shows how the probability would bemodified by the addition of mixing with a sterile neutrino
Figure 22 MINOS+ has the potential to rule out much of theLSND allowed region MINOS+ will begin taking data in thelate summer of 2013 and will continue taking data for at leasttwo years (Figure 22 assumes two years of data taking with aneutrino-dominated beam)
8 Conclusion
The MINOS experiment was conceived at a time when neu-trino oscillation had only recently been confirmed as thesolution to the problem of neutrino flavour change It has
Advances in High Energy Physics 15
Δm
2
10minus210minus2
10minus1
10minus1
10minus310minus4 1
1
10
102
LSND 90 CLLSND 99 CLKarmen2 90 CLBugey 90 CLlowast
MiniBooNE 90 CLMiniBooNE 99 CLMINOS+ and Bugeycombination 90 CL
sin22120579120583e
lowastGLoBES 2012 fit with new reactor fluxescourtesy of P Huber
Figure 22 The sensitivity of MINOS+ to the existence of sterileneutrinos when combined with data from the Bugey [85] reactorneutrino experiment Δ1198982 is the splitting between the three knownneutrino mass states and a new fourth state 120579
120583119890is the mixing angle
governing ]120583rarr ]119890transitions when a fourth sterile neutrino state
is introduced into the PMNSmixingmatrixThis figure assumes twoyears of MINOS+ running with a neutrino-dominated beam
played a hugely influential role in bringing neutrino oscilla-tion physics into an era of precision measurement MINOSrsquosmeasurement of the largest neutrino mass splitting is themost precise in the world MINOS has made the first directprecision measurement of the corresponding antineutrinoparameters a measurement that promises to remain theworldrsquos most precise for many years And MINOS has playeda role in the discovery of a nonzero value for 120579
13
Now that the value of 12057913is known the neutrino physics
community can move on to determine the neutrino masshierarchy and to search for CP violation in the neutrinosector MINOS has pioneered a number of techniques thatwill be used by future experiments The two-detector setupall important in reducing the impact of systematic uncer-tainties is the design of choice for any new experiment andMINOS has demonstrated methods of using a near detectorto determine the expectation at a far detector MINOS hasperformed the first search for ]
119890appearance in a ]
120583beam
and the first search for ]119890and ]119890appearance with significant
matter effects demonstrating the analysis techniques that willbe used to determine the mass hierarchy and CP violationparameter
In the second half of 2013 MINOS will begin taking dataas the MINOS+ experiment which will make ever more pre-cise tests of the three-flavour neutrino oscillation paradigmand set world-leading limits on the existence of sterileneutrinos This is an exciting future for an experiment thatwith a decade of data taking so far has already created alasting legacy for itself in our understanding of the neutrino
A comparison of themeasured neutrino and antineutrinomass splittings is shown in Figure 14 the difference betweenthe two is constrained to |Δ119898
2| minus |Δ119898
2| = (012
+024
minus026) times
10minus3 eV2
Acknowledgment
The work of the MINOS and MINOS+ collaborations issupported by the US DoE the UK STFC the US NSF theState and University of Minnesota the University of Athensin Greece and Brazilrsquos FAPESP and CNPq The authors aregrateful to the Minnesota Department of Natural Resourcesthe crew of the Soudan Underground Laboratory and thepersonnel of Fermilab for their vital contributions
References
[1] S Wojcicki ldquoLong baseline neutrino oscillation programe inthe United Statesrdquo Nuclear Physics B vol 77 no 1ndash3 pp 182ndash186 1999 Proceedings of the 18th International Conference onNeutrino Physics and Astrophysics (Neutrino rsquo98) TakayamaJapan June 1998
[2] R Davis Jr D S Harmer and K C Hoffman ldquoSearch forneutrinos from the sunrdquo Physical Review Letters vol 20 no 21pp 1205ndash1209 1968
[3] A I Abazov O L Anosov E L Faizov et al ldquoSearch forneutrinos from sun using the reactionGa-71 (electron-neutrinoe-) Ge-71rdquo Physical Review Letters vol 67 pp 3332ndash3335 1991
[4] P Anselmann W Hampel G Heusser et al ldquoSolar neutrinosobserved by GALLEX at gran sassordquo Physics Letters B vol 285no 4 pp 376ndash389 1992
[5] M Aglietta G Battistoni E Bellotti et al ldquoExperimentalstudy of atmospheric neutrino flux in the NUSEX experimentrdquoEurophysics Letters vol 8 no 7 article 611 1989
[6] K S Hirata ldquoObservation of a small atmospheric V120583V119890ratio in
Kamiokanderdquo Physics Letters B vol 280 no 1-2 pp 146ndash1521992
[7] R Becker-Szendy C B Bratton D Casper et al ldquoElectron-and muon-neutrino content of the atmospheric fluxrdquo PhysicalReview D vol 46 pp 3720ndash3724 1992
[8] K Daum W Rhode P Bareyre et al ldquoDetermination ofthe atmospheric neutrino spectra with the frejus detectorrdquoZeitschrift fur Physik C vol 66 no 3 pp 417ndash428 1995
[9] S Ahlen M Ambrosio R Antolini and G Auriemma ldquoAtmo-spheric neutrino flux measurement using upgoing muonsrdquoPhysics Letters B vol 357 no 3 pp 481ndash486 1995
[10] WMAllison G J Alner D S Ayres et al ldquoMeasurement of theatmospheric neutrino flavour composition in Soudan 2rdquoPhysicsLetters B vol 391 no 3-4 pp 491ndash500 1997
16 Advances in High Energy Physics
[11] Y Fukuda T Hayakawa E Ichihara et al ldquoEvidence foroscillation of atmospheric neutrinosrdquo Physical Review Lettersvol 81 no 8 pp 1562ndash1567 1998
[12] Q R Ahmad R C Allen T C Andersen et al ldquoMeasurementof charged current interactions produced by solar neutrinos atthe sudbury neutrino observatoryrdquo Physical Review Letters vol87 Article ID 071301 2001
[13] Q R Ahmad R C Allen T C Andersen et al ldquoDirect evidencefor neutrino flavor transformation from neutral-current inter-actions in the sudbury neutrino observatoryrdquo Physical ReviewLetters vol 89 Article ID 011301 6 pages 2002
[14] B Pontecorvo ldquoInverse beta processes and nonconservation oflepton chargerdquo Journal of Experimental and Theoretical Physicsvol 34 pp 172ndash173 1958
[15] V N Gribov and B Pontecorvo ldquoNeutrino astronomy andlepton chargerdquo Physics Letters B vol 28 pp 493ndash496 1969
[16] Z Maki M Nakagawa and S Sakata ldquoRemarks on the unifiedmodel of elementary particlesrdquo Progress of Theoretical Physicsvol 28 no 5 pp 870ndash880 1962
[17] P Adamson C Andreopoulos D J Auty et al ldquoFirst directobservation of muon antineutrino disappearancerdquo PhysicalReview Letters vol 107 no 2 Article ID 021801 2011
[18] P Adamson D J Auty D S Ayres et al ldquoSearch for thedisappearance of muon antineutrinos in the NuMI neutrinobeamrdquo Physical Review D vol 84 no 7 Article ID 071103 6pages 2011
[19] P Adamson D S Ayres C Backhouse et al ldquoImprovedmeasurement of muon antineutrino disappearance inMINOSrdquoPhysical Review Letters vol 108 no 19 Article ID 191801 5pages 2012
[20] P Adamson I Anghel C Backhouse et al ldquoMeasurementof Neutrino and Antineutrino Oscillations Using Beam andAtmospheric Data in MINOSrdquo Physical Review Letters vol 110no 25 Article ID 251801 6 pages 2013
[21] K Anderson B Bernstein D Boehnlein et al ldquoThe NuMIFacility Technical Design Reportrdquo FERMILAB-DESIGN-1998-01 1998
[22] D G Michael P Adamson T Alexopoulos et al ldquoObservationof muon neutrino disappearance with the MINOS detectors inthe NuMI neutrino beamrdquo Physical Review Letters vol 97 no19 Article ID 191801 6 pages 2006
[23] P Adamson C Andreopoulos K E Arms et al ldquoStudy ofmuon neutrino disappearance using the fermilab main injectorneutrino beamrdquo Physical Review D vol 77 no 7 Article ID072002 34 pages 2008
[24] P Adamson C Andreopoulos K E Arms et al ldquoMeasurementof neutrino oscillations with theMINOS detectors in the NuMIbeamrdquo Physical Review Letters vol 101 no 13 Article ID 1318025 pages 2008
[25] P Adamson C Andreopoulos R Armstrong et al ldquoMea-surement of the neutrino mass splitting and flavor mixing byMINOSrdquo Physical Review Letters vol 106 no 18 Article ID181801 6 pages 2011
[26] P Adamson C Andreopoulos K E Arms et al ldquoSearch formuon-neutrino to electron-neutrino transitions in MINOSrdquoPhysical Review Letters vol 103 no 26 Article ID 261802 5pages 2009
[27] PAdamsonCAndreopoulosD J Auty et al ldquoNew constraintsonmuon-neutrino to electron-neutrino transitions inMINOSrdquoPhysical ReviewD vol 82 no 5 Article ID 051102 6 pages 2010
[28] P Adamson D J Auty D S Ayres et al ldquoImproved search formuon-neutrino to electron-neutrino oscillations in MINOSrdquoPhysical Review Letters vol 107 no 18 Article ID 181802 6pages 2011
[29] P Adamson I Anghel C Backhouse et al ldquoElectron neutrinoand antineutrino appearance in the full MINOS data samplerdquoPhysical Review Letters vol 110 no 17 Article ID 171801 6 pages2013
[30] P Adamson C Andreopoulos K E Arms et al ldquoSearch foractive neutrino disappearance using neutral-current interac-tions in theMINOS long-baseline experimentrdquo Physical ReviewLetters vol 101 no 22 Article ID 221804 5 pages 2008
[31] P Adamson C Andreopoulos D J Auty et al ldquoSearch for ster-ile neutrino mixing in the MINOS long-baseline experimentrdquoPhysical Review D vol 81 no 5 Article ID 052004 18 pages2010
[32] P Adamson D J Auty D S Ayres et al ldquoActive to sterileneutrino mixing limits from neutral-current interactions inMINOSrdquo Physical Review Letters vol 107 no 1 Article ID011802 5 pages 2011
[33] Z Pavlovic Observation of disappearance of muon neutrinos inthe NuMI beam [PhD thesis] University of Texas at AustinAustin Tex USA 2008
[34] F Ballarini G Battistoni M Campanella et al ldquoThe FLUKAcode an overviewrdquo Journal of Physics vol 41 article 151 2006
[35] S Agostinelli J Allison K Amako et al ldquoGEANT4mdasha sim-ulation toolkitrdquo Nuclear Instruments and Methods in PhysicsResearch A vol 506 no 3 pp 250ndash303 2003
[36] G Battistoni F Cerutti A Fasso et al ldquoThe FLUKA codedescription and benchmarkingrdquo in Proceedings of the HadronicShower Simulation Workshop vol 896 of AIP Conference Pro-ceedings pp 31ndash49 Batavia Ill USA September 2006
[37] D G Michaele P Adamson T Alexopoulos et al ldquoThe mag-netized steel and scintillator calorimeters of the MINOS exper-imentrdquoNuclear Instruments and Methods in Physics Research Avol 596 no 2 pp 190ndash228 2008
[38] I E Stockdale A Bodek F Borcherding N Giokaris et alldquoLimits on muon-neutrino oscillations in the mass range 30 lt9987791198982lt 1000 eV2c4 rdquo Physical Review Letters vol 52 no 16 pp
1384ndash1388 1984[39] F Dydak G J Feldman C Guyot et al ldquoA search for V
120583
oscillations in the9987791198982 range 03ndash90 eV2 rdquo Physics Letters B vol134 no 3-4 pp 281ndash286 1984
[40] F Bergsma J Dorenbosch M Jonker et al ldquoA searchfor oscillations of muon neutrinos in an experiment withLEcong07 kmGeVrdquo Physics Letters B vol 142 no 1-2 pp 103ndash1101984
[41] M H Ahn E Aliu S Andringa et al ldquoMeasurement ofneutrino oscillation by the K2K experimentrdquo Physical ReviewD vol 74 no 7 Article ID 072003 39 pages 2006
[42] P Adamson T Alexopoulos W W M Allison et al ldquoFirstobservations of separated atmospheric V
120583and ]
120583events in the
MINOS detectorrdquo Physical Review D vol 73 no 7 Article ID072002 2006
[43] P Adamson C Andreopoulos K E Arms et al ldquoCharge-separated atmospheric neutrino-inducedmuons in theMINOSfar detectorrdquo Physical ReviewD vol 75 no 9 Article ID 09200314 pages 2007
[44] P Adamson C Backhouse G Barr et al ldquoMeasurements ofatmospheric neutrinos and antineutrinos in the MINOS fardetectorrdquo Physical Review D vol 86 no 5 Article ID 05200720 pages 2012
Advances in High Energy Physics 17
[45] M A Kordosky Hadronic interactions in the MINOS detectors[PhD thesis] University of Texas at Austin Austin Tex USA2004
[46] P L Vahle Electromagnetic interactions in the MINOS detectors[PhD thesis] University of Texas at Austin Austin Tex USA2004
[47] C Backhouse Measuring neutrino oscillation parameters using]120583disappearance inMINOS [PhD thesis] University of Oxford
Oxford UK 2011[48] T M Cover and P E Hart ldquoNearest neighbor pattern classifi-
cationrdquo IEEE Transactions on Information Theory vol 13 no 1pp 21ndash27 1967
[49] R Ospanov A measurement of muon neutrino disappearancewith the MINOS detectors and NuMI beam [PhD thesis]University of Texas at Austin Austin Tex USA 2008
[50] J S Marshall A study of muon neutrino disappearance with theMINOS detectors and the NuMI neutrino beam [PhD thesis]University of Cambridge Cambridge UK 2008
[51] J P OchoaA search formuon neutrino to electron neutrino oscil-lations in the MINOS Experiment [PhD thesis] The CaliforniaInstitute of Technology Pasadena Calif USA 2009
[52] R TonerMeasuring 12057913via muon neutrino to electron neutrino
oscillations in the MINOS experiment [PhD thesis] Universityof Cambridge Cambridge UK 2011
[53] A Holin Electron neutrino appearance in the MINOS experi-ment [PhD thesis] University College London London UK2010
[54] J Boehm Measurement of electron neutrino appearance withthe MINOS experiment [PhD thesis] Harvard UniversityCambridge Mass USA 2009
[55] G Tinti Sterile neutrino oscillations in MINOS and hadronproduction in pC collisions [PhD thesis] University of OxfordOxford UK 2010
[56] J J EvansMeasuring antineutrino oscillations with the MINOSexperiment [PhD thesis] University of Oxford Oxford UK2008
[57] S J ColemanAmeasurement of neutrino oscillations withmuonneutrinos in the MINOS experiment [PhD thesis] College ofWilliam ampMary Williamsburg Va USA 2011
[58] J S Mitchell Measuring ]120583disappearance with the MINOS
experiment [PhD thesis] University of Cambridge CambridgeUK 2011
[59] A McGowan Observation of deficit in NuMI neutrino-inducedrock and non-fiducial muons in MINOS far detector andmeasurement of neutrino oscillation parameters [PhD thesis]University of Minnesota Minneapolis Minn USA 2007
[60] M StraitMeasurement of neutrino oscillation parameters usinganti-fiducial charged current events in MINOS [PhD thesis]University of Minnesota Minneapolis Minn USA 2010
[61] Y Itow ldquoAtmospheric neutrinosmdashresults from running exper-imentsrdquo in Proceedings of the 25th International Conference onNeutrino Physics and Astrophysics (Neutrino rsquo12) Kyoto JapanJune 2012
[62] K Abe N Abgrall Y Ajima et al ldquoFirst muon-neutrinodisappearance study with an off-axis beamrdquo Physical Review Dvol 85 no 3 Article ID 031103 8 pages 2012
[63] K Nakamura ldquoReview of particle physicsrdquo Journal of Physics Gvol 37 Article ID 075021 2010
[64] L Wolfenstein ldquoNeutrino oscillations in matterrdquo PhysicalReview D vol 17 no 9 pp 2369ndash2374 1978
[65] J W F Valle ldquoResonant oscillations of massless neutrinos inmatterrdquo Physics Letters B vol 199 no 3 pp 432ndash436 1987
[66] M C Gonzalez-Garcia M M Guzzo P I Krastev et alldquoAtmospheric neutrino observations and flavor changing inter-actionsrdquo Physical Review Letters vol 82 no 16 pp 3202ndash32051999
[67] A Friedland C Lunardini and M Maltoni ldquoAtmosphericneutrinos as probes of neutrino-matter interactionsrdquo PhysicalReview D vol 70 no 11 Article ID 111301 2004
[68] Z IsvanAntineutrino oscillations and a Search for non-standardInteractions with the MINOS [PhD thesis] University of Pitts-burgh Pittsburgh Pa USA 2012
[69] W A Mann D Cherdack W Musial and T Kafka ldquoApparentmultiple 998779119898
32
2 in ]120583and V
120583survival oscillations from nonstan-
dard interactionmatter effectrdquo Physical Review D vol 82 no 11Article ID 113010 8 pages 2010
[70] J Kopp P A N Machado and S J Parke ldquoInterpretation ofMINOS data in terms of nonstandard neutrino interactionsrdquoPhysical Review D vol 82 no 11 Article ID 113002 12 pages2010
[71] J A B Coelho Investigacao de mecanismos alternativos aoscilacao de neutrinos no experimentos MINOS [PhD thesis]Universidade Estadual de Campinas Sao Paulo Brazil 2012
[72] F P An Q An J Z Bai A B Balantekin et al ldquoImprovedmeasurement of electron antineutrino disappearance at DayaBayrdquo Chinese Physics C vol 37 Article ID 011001 21 pages 2013
[73] J K Ahn S Chebotaryov J H Choi et al ldquoObservationof reactor electron antineutrinos disappearance in the RENOexperimentrdquo Physical Review Letters vol 108 Article ID 1918026 pages 2012
[74] Y Abe C Aberle J C dos Anjos et al ldquoReactor electronantineutrino disappearance in the Double Chooz experimentrdquoPhysical Review D vol 86 Article ID 052008 2012
[75] K Abe N Abgrall H Aihara et al ldquoEvidence of electronneutrino appearance in a muon neutrino beamrdquo PhysicalReview D vol 88 no 3 Article ID 032002 41 pages 2013
[76] A Schreckenberger Electron neutrino and antineutrino appear-ance in the MINOS detector [PhD thesis] University of Min-nesota Minneapolis Minn USA 2013
[77] D J Koskinen MINOS sterile neutrino search [PhD thesis]University College London London UK 2009
[78] M Apollonio A Baldini C Bemporad et al ldquoSearch forneutrino oscillations on a long base-line at the CHOOZ nuclearpower stationrdquoTheEuropean Physical Journal C vol 27 pp 331ndash374 2003
[79] G Tzanankos M Bishai M Diwan et alMINOS+ a proposalto FNAL to run MINOS with the medium energy NuMI beam[PhD thesis] University of Athens Athens Greece 2011
[80] A Aguilar L B Auerbach R L Burman et al ldquoEvidence forneutrino oscillations from the observation of ]
119890e appearance
in a ]120583beamrdquo Physical Review D vol 64 Article ID 112007 22
pages 2001[81] A A Aguilar-Arevalo C E Anderson S J Brice et al ldquoSearch
for electron antineutrino appearance at the Δ119898 sim 1 eV2 ScalerdquoPhysical Review Letters vol 103 no 11 Article ID 111801 2009
[82] A A Aguilar-Arevalo C E Anderson A O Bazarko et alldquoImproved search for V
120583rarr V119890oscillations in the MiniBooNE
experimentrdquo Physical Review Letter vol 110 no 10 Article ID161801 2013
[83] GMentionM Fechner T Lasserre et al ldquoReactor antineutrinoanomalyrdquo Physical Review D vol 83 Article ID 073006 20pages 2011
18 Advances in High Energy Physics
[84] KNAbazajianMAAcero S KAgarwalla et al ldquoLight sterileneutrinos a white paperrdquo httparxivorgabs12045379
[85] B Achkar R Aleksan M Avenier et al ldquoSearch for neutrinooscillations at 15 40 and 95meters from a nuclear power reactorat Bugeyrdquo Nuclear Physics B vol 434 no 3 pp 503ndash532 1995
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
High Energy PhysicsAdvances in
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
FluidsJournal of
Atomic and Molecular Physics
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in Condensed Matter Physics
OpticsInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
AstronomyAdvances in
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Superconductivity
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Statistical MechanicsInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
GravityJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
AstrophysicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Physics Research International
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Solid State PhysicsJournal of
Computational Methods in Physics
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Soft MatterJournal of
Hindawi Publishing Corporationhttpwwwhindawicom
AerodynamicsJournal of
Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
PhotonicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Biophysics
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
ThermodynamicsJournal of
Advances in High Energy Physics 11
Reconstructed energy (GeV)0 6 8
Frac
tion
of ev
ents
0
01
02
03
04
Standard MC
MINOS
2 4
Near detector 2011
NC120583-CCe-CC
(a)
Horn-off MC
Reconstructed energy (GeV)0 6 8
Frac
tion
of ev
ents
0
01
02
03
04 MINOS
2 4
Near detector 2011
NC120583-CCe-CC
(b)
High energy MC
Reconstructed energy (GeV)0 6 8
Frac
tion
of ev
ents
0
01
02
03
04 MINOS
2 4
Near detector 2011
NC120583-CCe-CC
(c)
Figure 15 The contribution of the three components to the background in the ]119890appearance search as simulated in the ND (a) the regular
(low energy) beam data (b) with no current in the NuMI focusing horns (c) a high energy beam configuration
for ]119890and ]119890appearance with significant matter effects Both
of these effects provide some sensitivity to the neutrinomass hierarchy and CP violation when the MINOS data iscompared to the measurements made by reactor neutrinosearches [72ndash74] (we have calculated a limit of sin2(2120579
13) =
0098 plusmn 0013 from the reactor data at the time of analysis)The sensitivity of MINOS to the mass hierarchy and CPviolation is modest but this contributes to the first analysisof the type that will be used by all future long-baselineexperiments The resulting values of the likelihood by whichMINOS disfavours various values of these parameters areshown in Figure 18 [76]
6 Search for Sterile Neutrino Mixing UsingNeutral-Current Interactions
The energy spectrum of NC interactions in the FD should beunchanged by standard neutrino oscillationThe existence ofone or more sterile neutrino flavours ]
119904 could cause a deficit
in the observed NC interaction rate As with all the MINOSoscillation analyses the energy spectrum of NC interactionsobserved in the ND (which was shown in Figure 8) is usedto predict the spectrum expected at the FD [77] The FDexpectation is shown in Figure 19 with the dashed blue linetaking into account ]
119890appearance corresponding to 120579
13=
115∘ (at the limit set by CHOOZ [78] and a little above
the current accepted value [29 72ndash75] this analysis usesonly the first 707 times 10
20 protons on target of data andwas performed before the recent positive measurements ofa nonzero 120579
13) The data are also shown in the figure and
are in good agreement with the expectation confirming thestandard model of neutrino oscillation This agreement canbe quantified using a test statistic 119877
119877 =119873data minus 119861CC
119878NC (7)
where 119873data is the number of events observed 119861CC is thepredicted background of CC interactions and 119878NC is the
predicted number of NC interactions A value of 119877 = 101 plusmn
006(stat) plusmn 005(syst) is obtained (over the full energy range0ndash120GeV) which is in good agreement with the expectationof 119877 = 1 in the case of no mixing with sterile neutrinos
The data are analysed with a model that assumes a singlesterile neutrino flavour mixing through the addition of afourth neutrino mass state119898
4≫ 1198983 This introduces a mass
splitting Δ119898243
with magnitude O(1 eV2) such that no oscil-lation-induced change to the event rate is observed at theND and the oscillatory energy dependence of the induceddepletion at the FD is so rapid that an overall uniform deple-tion is observed once the energy resolution of the detectors isaccounted forThismodel introduces three additionalmixingangles 120579
14 12057924 and 120579
34 MINOS is insensitive to 120579
14but sets
limits of 12057924= (00
+5
minus00)∘ and 120579
34= (00
+25
minus00)∘ These limits are
evaluated assuming 12057913at the CHOOZ limit
The limit on the coupling of sterile to active neutrinos canbe quantified by defining 119891
119904 the fraction of disappearing ]
120583
which have oscillated into ]119904
119891119904=
119875]120583rarr ]119904
1 minus 119875]120583rarr ]120583
(8)
For the model used in which 1198984≫ 119898
3 119891119904is evaluated
at 14 GeV the energy of maximal ]120583disappearance To
determine the limit on 119891119904 a large number of test values
are chosen of the mixing angles 12057924 12057934 and 120579
23 from
Gaussian distributions according to the measured values and1120590 uncertainties given above (with 120579
23constrained from the
measurements with CC ]120583interactions) 119891
119904is calculated for
each case and the value of 119891119904that is larger than 90 of the
test cases represents the limit MINOS limits 119891119904lt 040 at the
90 confidence level
7 The Future MINOS+
The MINOS experiment has made some very importantcontributions to our understanding of neutrino oscillation
12 Advances in High Energy Physics
Reconstructed energy (GeV)
Reconstructed energy (GeV)
Even
ts
30
0
10
20
Even
ts
30
0
10
20
Even
ts
30
0
10
20
2 4 6 8
2 4 6 8
Reconstructed energy (GeV)2 4 6 8
06 lt 120572LEM lt 07
MINOS far detector data
07 lt 120572LEM lt 08
120572LEM gt 08
mode
mode
mode
e CC signal
e CC signalBackgroundData
(a)
Even
ts
Reconstructed energy (GeV)2 4 6 8
Reconstructed energy (GeV)2 4 6 8
Reconstructed energy (GeV)2 4 6 8
06 lt 120572LEM lt 07
MINOS far detector data
Merged for fit
07 lt 120572LEM lt 08
120572LEM gt 08
mode
mode
mode
8
6
4
2
0
Even
ts
8
6
4
2
0
Even
ts
8
6
4
2
0
e CC signal
e CC signalBackgroundData
5ndash8GeV bins
(b)
Figure 16 The CC ]119890(a) and ]
119890(b) candidate events selected in the FD compared to the expectation without any ]
119890appearance (red) and
with the best fit for 12057913(purple) The events are divided into bins of the library event matching discriminant variable
Advances in High Energy Physics 13
20
15
10
05
000 01 02 03 04
2sin2(212057913)sin212057923
Δm2 gt 0
sin
120575(120587)
(a)
20
15
10
05
000 01 02 03 04
2sin2(212057913)sin212057923
MINOS best fit 12057923 lt 1205874
MINOS best fit 12057923 gt 1205874
Δm2 lt 0
MINOS
106 times 1020 POT -mode33 times 1020 POT -mode
68 CL 12057923 lt 1205874
90 CL 12057923 lt 1205874
120575(120587)
(b)
Figure 17 The allowed regions for 2sin2(212057913)sin2(120579
23)
120575(120587)
Δm2 gt 0 12057923 gt 1205874
Δm2 gt 0 12057923 lt 1205874
Δm2 lt 0 12057923 gt 1205874Δm2 lt 0 12057923 lt 1205874
3
2
1
00 1 1505 2
MINOS
90 CL
68 CL
minus2Δ
(L)
ln
Figure 18 The values of likelihood 119871 by which various values oftheCP violating parameter 120575 the mass hierarchy and the octant of12057923are disfavouredThis analysis uses MINOS data and information
from reactor neutrino measurements of 12057913[72ndash74]
physics and has finished taking data with the low energybeam for which it was designed However the experimentwill continue taking data and producing new results for thenext few years as MINOS+ [79] The NuMI beam is being
20
2018161410 12
Far detector data
Even
ts (G
eV)
00 2 4 6 8
40
60
80
100
120
140
12057913 = 0∘
12057913 = 115∘ 120575 = 120587 Δm232 gt 0
120583 CC background|Δm2
32| = 232 times 10minus3eV2
Ereco (GeV)
sin2212057923 = 1
Figure 19 The black dots show the energy spectrum of NCinteractions observed in the far detector The red lines show theexpectation in the case of no sterile neutrinos and 120579
13= 0 the blue
dashed line shows the same expectation with 12057913= 115
∘
upgraded to a higher energy and intensity for the NO]Aexperiment the far detector of which will sit 14 mrad offaxisNO]A will receive a narrow-band beam peaking at around2GeV which is ideal for searching for ]
119890appearance since
the background seen in MINOS from NC interactions ofhigh energy neutrinos will be heavily reduced Figure 20shows that the MINOS FD will see an intense ]
120583beam
14 Advances in High Energy Physics
1000
500
00 5 10 15 20
E (GeV)
MINOS+NOAMINOS
Preliminary
Simulated beam54 kton 6 times 1020 POT
120583CC
even
ts (G
eV)
Figure 20 The ]120583energy spectrum that will be observed by the
MINOS+ FD compared to the spectra observed by MINOS andNO]A
peaking at around 7GeV In this configuration MINOS+ willobserve around 4000 CC ]
120583interactions in the FD each
year unprecedented statistics for a long-baseline oscillationexperimentThis will offer a unique high precision test of thethree-flavour oscillation paradigm
MINOS+ will be able to make a very sensitive searchfor the sterile neutrinos suggested by the LSND [80] andMiniBooNE [81 82] data and by some interpretations ofreactor neutrino data [83] This search will cover more thanthree orders of magnitude in the mass splitting between thesterile and active neutrinos The signal that MINOS+ willsearch for is illustrated in Figure 21 Figure 21(a) illustratesthe increase in statistical precision thatMINOS+will provideon the ratio of the observed CC ]
120583interaction rate to
that expected without oscillations Figure 21(b) shows howthis ratio is modified if a sterile neutrino exists and mixeswith the active neutrinos an additional deficit of muonneutrino interactions occurs in the higher energy region ofthe spectrum In the model assumed here which introducesa single sterile neutrino state three new mixing angles areintroduced 120579
14 12057924 and 120579
34 An additional mass splitting
Δ1198982
43is also introduced The position in energy of the
additional deficit is governed by the value of the new masssplittingThemagnitude of the additional deficit in the CC ]
120583
interaction rate is governed primarily by the size of 12057924 this is
in comparison to short-baseline searches for ]119890disappearance
from reactors which are governed by 12057914and searches for ]
119890
appearance in ]120583beamswhich are governed by a combination
of 12057914
and 12057924 A detailed explanation of the global effort to
search for sterile neutrinos can be found in [84]The sensitivity of the MINOS+ experiment when com-
bined with the Bugey reactor neutrino data [85] is shown in
MINOS+ simulation
MINOS 1071 times 1021 POT06 times 1021 POT12 times 1021 POT18 times 1021 POT
120583su
rviv
al p
roba
bilit
y
Neutrino energy (GeV)0 5 10 15
15
1
05
0
(a)
P(
120583rarr
120583)
No sterile neutrinosΔm2
43 = 2 times 10minus2eV2 sin2(212057924) = 02
0 5 10 15 20
1
0
18
06
04
02
Neutrino energy (GeV)
(b)
Figure 21 (a) The black points show the ratio of the observed ]120583
energy spectrum to the expectation in the case of no oscillation inthe neutrino-dominated beam of MINOS The blue region showsthe statistical precision expected from MINOS+ (b) The black lineshows the muon neutrino survival probability in the case of nosterile neutrinos the red line shows how the probability would bemodified by the addition of mixing with a sterile neutrino
Figure 22 MINOS+ has the potential to rule out much of theLSND allowed region MINOS+ will begin taking data in thelate summer of 2013 and will continue taking data for at leasttwo years (Figure 22 assumes two years of data taking with aneutrino-dominated beam)
8 Conclusion
The MINOS experiment was conceived at a time when neu-trino oscillation had only recently been confirmed as thesolution to the problem of neutrino flavour change It has
Advances in High Energy Physics 15
Δm
2
10minus210minus2
10minus1
10minus1
10minus310minus4 1
1
10
102
LSND 90 CLLSND 99 CLKarmen2 90 CLBugey 90 CLlowast
MiniBooNE 90 CLMiniBooNE 99 CLMINOS+ and Bugeycombination 90 CL
sin22120579120583e
lowastGLoBES 2012 fit with new reactor fluxescourtesy of P Huber
Figure 22 The sensitivity of MINOS+ to the existence of sterileneutrinos when combined with data from the Bugey [85] reactorneutrino experiment Δ1198982 is the splitting between the three knownneutrino mass states and a new fourth state 120579
120583119890is the mixing angle
governing ]120583rarr ]119890transitions when a fourth sterile neutrino state
is introduced into the PMNSmixingmatrixThis figure assumes twoyears of MINOS+ running with a neutrino-dominated beam
played a hugely influential role in bringing neutrino oscilla-tion physics into an era of precision measurement MINOSrsquosmeasurement of the largest neutrino mass splitting is themost precise in the world MINOS has made the first directprecision measurement of the corresponding antineutrinoparameters a measurement that promises to remain theworldrsquos most precise for many years And MINOS has playeda role in the discovery of a nonzero value for 120579
13
Now that the value of 12057913is known the neutrino physics
community can move on to determine the neutrino masshierarchy and to search for CP violation in the neutrinosector MINOS has pioneered a number of techniques thatwill be used by future experiments The two-detector setupall important in reducing the impact of systematic uncer-tainties is the design of choice for any new experiment andMINOS has demonstrated methods of using a near detectorto determine the expectation at a far detector MINOS hasperformed the first search for ]
119890appearance in a ]
120583beam
and the first search for ]119890and ]119890appearance with significant
matter effects demonstrating the analysis techniques that willbe used to determine the mass hierarchy and CP violationparameter
In the second half of 2013 MINOS will begin taking dataas the MINOS+ experiment which will make ever more pre-cise tests of the three-flavour neutrino oscillation paradigmand set world-leading limits on the existence of sterileneutrinos This is an exciting future for an experiment thatwith a decade of data taking so far has already created alasting legacy for itself in our understanding of the neutrino
A comparison of themeasured neutrino and antineutrinomass splittings is shown in Figure 14 the difference betweenthe two is constrained to |Δ119898
2| minus |Δ119898
2| = (012
+024
minus026) times
10minus3 eV2
Acknowledgment
The work of the MINOS and MINOS+ collaborations issupported by the US DoE the UK STFC the US NSF theState and University of Minnesota the University of Athensin Greece and Brazilrsquos FAPESP and CNPq The authors aregrateful to the Minnesota Department of Natural Resourcesthe crew of the Soudan Underground Laboratory and thepersonnel of Fermilab for their vital contributions
References
[1] S Wojcicki ldquoLong baseline neutrino oscillation programe inthe United Statesrdquo Nuclear Physics B vol 77 no 1ndash3 pp 182ndash186 1999 Proceedings of the 18th International Conference onNeutrino Physics and Astrophysics (Neutrino rsquo98) TakayamaJapan June 1998
[2] R Davis Jr D S Harmer and K C Hoffman ldquoSearch forneutrinos from the sunrdquo Physical Review Letters vol 20 no 21pp 1205ndash1209 1968
[3] A I Abazov O L Anosov E L Faizov et al ldquoSearch forneutrinos from sun using the reactionGa-71 (electron-neutrinoe-) Ge-71rdquo Physical Review Letters vol 67 pp 3332ndash3335 1991
[4] P Anselmann W Hampel G Heusser et al ldquoSolar neutrinosobserved by GALLEX at gran sassordquo Physics Letters B vol 285no 4 pp 376ndash389 1992
[5] M Aglietta G Battistoni E Bellotti et al ldquoExperimentalstudy of atmospheric neutrino flux in the NUSEX experimentrdquoEurophysics Letters vol 8 no 7 article 611 1989
[6] K S Hirata ldquoObservation of a small atmospheric V120583V119890ratio in
Kamiokanderdquo Physics Letters B vol 280 no 1-2 pp 146ndash1521992
[7] R Becker-Szendy C B Bratton D Casper et al ldquoElectron-and muon-neutrino content of the atmospheric fluxrdquo PhysicalReview D vol 46 pp 3720ndash3724 1992
[8] K Daum W Rhode P Bareyre et al ldquoDetermination ofthe atmospheric neutrino spectra with the frejus detectorrdquoZeitschrift fur Physik C vol 66 no 3 pp 417ndash428 1995
[9] S Ahlen M Ambrosio R Antolini and G Auriemma ldquoAtmo-spheric neutrino flux measurement using upgoing muonsrdquoPhysics Letters B vol 357 no 3 pp 481ndash486 1995
[10] WMAllison G J Alner D S Ayres et al ldquoMeasurement of theatmospheric neutrino flavour composition in Soudan 2rdquoPhysicsLetters B vol 391 no 3-4 pp 491ndash500 1997
16 Advances in High Energy Physics
[11] Y Fukuda T Hayakawa E Ichihara et al ldquoEvidence foroscillation of atmospheric neutrinosrdquo Physical Review Lettersvol 81 no 8 pp 1562ndash1567 1998
[12] Q R Ahmad R C Allen T C Andersen et al ldquoMeasurementof charged current interactions produced by solar neutrinos atthe sudbury neutrino observatoryrdquo Physical Review Letters vol87 Article ID 071301 2001
[13] Q R Ahmad R C Allen T C Andersen et al ldquoDirect evidencefor neutrino flavor transformation from neutral-current inter-actions in the sudbury neutrino observatoryrdquo Physical ReviewLetters vol 89 Article ID 011301 6 pages 2002
[14] B Pontecorvo ldquoInverse beta processes and nonconservation oflepton chargerdquo Journal of Experimental and Theoretical Physicsvol 34 pp 172ndash173 1958
[15] V N Gribov and B Pontecorvo ldquoNeutrino astronomy andlepton chargerdquo Physics Letters B vol 28 pp 493ndash496 1969
[16] Z Maki M Nakagawa and S Sakata ldquoRemarks on the unifiedmodel of elementary particlesrdquo Progress of Theoretical Physicsvol 28 no 5 pp 870ndash880 1962
[17] P Adamson C Andreopoulos D J Auty et al ldquoFirst directobservation of muon antineutrino disappearancerdquo PhysicalReview Letters vol 107 no 2 Article ID 021801 2011
[18] P Adamson D J Auty D S Ayres et al ldquoSearch for thedisappearance of muon antineutrinos in the NuMI neutrinobeamrdquo Physical Review D vol 84 no 7 Article ID 071103 6pages 2011
[19] P Adamson D S Ayres C Backhouse et al ldquoImprovedmeasurement of muon antineutrino disappearance inMINOSrdquoPhysical Review Letters vol 108 no 19 Article ID 191801 5pages 2012
[20] P Adamson I Anghel C Backhouse et al ldquoMeasurementof Neutrino and Antineutrino Oscillations Using Beam andAtmospheric Data in MINOSrdquo Physical Review Letters vol 110no 25 Article ID 251801 6 pages 2013
[21] K Anderson B Bernstein D Boehnlein et al ldquoThe NuMIFacility Technical Design Reportrdquo FERMILAB-DESIGN-1998-01 1998
[22] D G Michael P Adamson T Alexopoulos et al ldquoObservationof muon neutrino disappearance with the MINOS detectors inthe NuMI neutrino beamrdquo Physical Review Letters vol 97 no19 Article ID 191801 6 pages 2006
[23] P Adamson C Andreopoulos K E Arms et al ldquoStudy ofmuon neutrino disappearance using the fermilab main injectorneutrino beamrdquo Physical Review D vol 77 no 7 Article ID072002 34 pages 2008
[24] P Adamson C Andreopoulos K E Arms et al ldquoMeasurementof neutrino oscillations with theMINOS detectors in the NuMIbeamrdquo Physical Review Letters vol 101 no 13 Article ID 1318025 pages 2008
[25] P Adamson C Andreopoulos R Armstrong et al ldquoMea-surement of the neutrino mass splitting and flavor mixing byMINOSrdquo Physical Review Letters vol 106 no 18 Article ID181801 6 pages 2011
[26] P Adamson C Andreopoulos K E Arms et al ldquoSearch formuon-neutrino to electron-neutrino transitions in MINOSrdquoPhysical Review Letters vol 103 no 26 Article ID 261802 5pages 2009
[27] PAdamsonCAndreopoulosD J Auty et al ldquoNew constraintsonmuon-neutrino to electron-neutrino transitions inMINOSrdquoPhysical ReviewD vol 82 no 5 Article ID 051102 6 pages 2010
[28] P Adamson D J Auty D S Ayres et al ldquoImproved search formuon-neutrino to electron-neutrino oscillations in MINOSrdquoPhysical Review Letters vol 107 no 18 Article ID 181802 6pages 2011
[29] P Adamson I Anghel C Backhouse et al ldquoElectron neutrinoand antineutrino appearance in the full MINOS data samplerdquoPhysical Review Letters vol 110 no 17 Article ID 171801 6 pages2013
[30] P Adamson C Andreopoulos K E Arms et al ldquoSearch foractive neutrino disappearance using neutral-current interac-tions in theMINOS long-baseline experimentrdquo Physical ReviewLetters vol 101 no 22 Article ID 221804 5 pages 2008
[31] P Adamson C Andreopoulos D J Auty et al ldquoSearch for ster-ile neutrino mixing in the MINOS long-baseline experimentrdquoPhysical Review D vol 81 no 5 Article ID 052004 18 pages2010
[32] P Adamson D J Auty D S Ayres et al ldquoActive to sterileneutrino mixing limits from neutral-current interactions inMINOSrdquo Physical Review Letters vol 107 no 1 Article ID011802 5 pages 2011
[33] Z Pavlovic Observation of disappearance of muon neutrinos inthe NuMI beam [PhD thesis] University of Texas at AustinAustin Tex USA 2008
[34] F Ballarini G Battistoni M Campanella et al ldquoThe FLUKAcode an overviewrdquo Journal of Physics vol 41 article 151 2006
[35] S Agostinelli J Allison K Amako et al ldquoGEANT4mdasha sim-ulation toolkitrdquo Nuclear Instruments and Methods in PhysicsResearch A vol 506 no 3 pp 250ndash303 2003
[36] G Battistoni F Cerutti A Fasso et al ldquoThe FLUKA codedescription and benchmarkingrdquo in Proceedings of the HadronicShower Simulation Workshop vol 896 of AIP Conference Pro-ceedings pp 31ndash49 Batavia Ill USA September 2006
[37] D G Michaele P Adamson T Alexopoulos et al ldquoThe mag-netized steel and scintillator calorimeters of the MINOS exper-imentrdquoNuclear Instruments and Methods in Physics Research Avol 596 no 2 pp 190ndash228 2008
[38] I E Stockdale A Bodek F Borcherding N Giokaris et alldquoLimits on muon-neutrino oscillations in the mass range 30 lt9987791198982lt 1000 eV2c4 rdquo Physical Review Letters vol 52 no 16 pp
1384ndash1388 1984[39] F Dydak G J Feldman C Guyot et al ldquoA search for V
120583
oscillations in the9987791198982 range 03ndash90 eV2 rdquo Physics Letters B vol134 no 3-4 pp 281ndash286 1984
[40] F Bergsma J Dorenbosch M Jonker et al ldquoA searchfor oscillations of muon neutrinos in an experiment withLEcong07 kmGeVrdquo Physics Letters B vol 142 no 1-2 pp 103ndash1101984
[41] M H Ahn E Aliu S Andringa et al ldquoMeasurement ofneutrino oscillation by the K2K experimentrdquo Physical ReviewD vol 74 no 7 Article ID 072003 39 pages 2006
[42] P Adamson T Alexopoulos W W M Allison et al ldquoFirstobservations of separated atmospheric V
120583and ]
120583events in the
MINOS detectorrdquo Physical Review D vol 73 no 7 Article ID072002 2006
[43] P Adamson C Andreopoulos K E Arms et al ldquoCharge-separated atmospheric neutrino-inducedmuons in theMINOSfar detectorrdquo Physical ReviewD vol 75 no 9 Article ID 09200314 pages 2007
[44] P Adamson C Backhouse G Barr et al ldquoMeasurements ofatmospheric neutrinos and antineutrinos in the MINOS fardetectorrdquo Physical Review D vol 86 no 5 Article ID 05200720 pages 2012
Advances in High Energy Physics 17
[45] M A Kordosky Hadronic interactions in the MINOS detectors[PhD thesis] University of Texas at Austin Austin Tex USA2004
[46] P L Vahle Electromagnetic interactions in the MINOS detectors[PhD thesis] University of Texas at Austin Austin Tex USA2004
[47] C Backhouse Measuring neutrino oscillation parameters using]120583disappearance inMINOS [PhD thesis] University of Oxford
Oxford UK 2011[48] T M Cover and P E Hart ldquoNearest neighbor pattern classifi-
cationrdquo IEEE Transactions on Information Theory vol 13 no 1pp 21ndash27 1967
[49] R Ospanov A measurement of muon neutrino disappearancewith the MINOS detectors and NuMI beam [PhD thesis]University of Texas at Austin Austin Tex USA 2008
[50] J S Marshall A study of muon neutrino disappearance with theMINOS detectors and the NuMI neutrino beam [PhD thesis]University of Cambridge Cambridge UK 2008
[51] J P OchoaA search formuon neutrino to electron neutrino oscil-lations in the MINOS Experiment [PhD thesis] The CaliforniaInstitute of Technology Pasadena Calif USA 2009
[52] R TonerMeasuring 12057913via muon neutrino to electron neutrino
oscillations in the MINOS experiment [PhD thesis] Universityof Cambridge Cambridge UK 2011
[53] A Holin Electron neutrino appearance in the MINOS experi-ment [PhD thesis] University College London London UK2010
[54] J Boehm Measurement of electron neutrino appearance withthe MINOS experiment [PhD thesis] Harvard UniversityCambridge Mass USA 2009
[55] G Tinti Sterile neutrino oscillations in MINOS and hadronproduction in pC collisions [PhD thesis] University of OxfordOxford UK 2010
[56] J J EvansMeasuring antineutrino oscillations with the MINOSexperiment [PhD thesis] University of Oxford Oxford UK2008
[57] S J ColemanAmeasurement of neutrino oscillations withmuonneutrinos in the MINOS experiment [PhD thesis] College ofWilliam ampMary Williamsburg Va USA 2011
[58] J S Mitchell Measuring ]120583disappearance with the MINOS
experiment [PhD thesis] University of Cambridge CambridgeUK 2011
[59] A McGowan Observation of deficit in NuMI neutrino-inducedrock and non-fiducial muons in MINOS far detector andmeasurement of neutrino oscillation parameters [PhD thesis]University of Minnesota Minneapolis Minn USA 2007
[60] M StraitMeasurement of neutrino oscillation parameters usinganti-fiducial charged current events in MINOS [PhD thesis]University of Minnesota Minneapolis Minn USA 2010
[61] Y Itow ldquoAtmospheric neutrinosmdashresults from running exper-imentsrdquo in Proceedings of the 25th International Conference onNeutrino Physics and Astrophysics (Neutrino rsquo12) Kyoto JapanJune 2012
[62] K Abe N Abgrall Y Ajima et al ldquoFirst muon-neutrinodisappearance study with an off-axis beamrdquo Physical Review Dvol 85 no 3 Article ID 031103 8 pages 2012
[63] K Nakamura ldquoReview of particle physicsrdquo Journal of Physics Gvol 37 Article ID 075021 2010
[64] L Wolfenstein ldquoNeutrino oscillations in matterrdquo PhysicalReview D vol 17 no 9 pp 2369ndash2374 1978
[65] J W F Valle ldquoResonant oscillations of massless neutrinos inmatterrdquo Physics Letters B vol 199 no 3 pp 432ndash436 1987
[66] M C Gonzalez-Garcia M M Guzzo P I Krastev et alldquoAtmospheric neutrino observations and flavor changing inter-actionsrdquo Physical Review Letters vol 82 no 16 pp 3202ndash32051999
[67] A Friedland C Lunardini and M Maltoni ldquoAtmosphericneutrinos as probes of neutrino-matter interactionsrdquo PhysicalReview D vol 70 no 11 Article ID 111301 2004
[68] Z IsvanAntineutrino oscillations and a Search for non-standardInteractions with the MINOS [PhD thesis] University of Pitts-burgh Pittsburgh Pa USA 2012
[69] W A Mann D Cherdack W Musial and T Kafka ldquoApparentmultiple 998779119898
32
2 in ]120583and V
120583survival oscillations from nonstan-
dard interactionmatter effectrdquo Physical Review D vol 82 no 11Article ID 113010 8 pages 2010
[70] J Kopp P A N Machado and S J Parke ldquoInterpretation ofMINOS data in terms of nonstandard neutrino interactionsrdquoPhysical Review D vol 82 no 11 Article ID 113002 12 pages2010
[71] J A B Coelho Investigacao de mecanismos alternativos aoscilacao de neutrinos no experimentos MINOS [PhD thesis]Universidade Estadual de Campinas Sao Paulo Brazil 2012
[72] F P An Q An J Z Bai A B Balantekin et al ldquoImprovedmeasurement of electron antineutrino disappearance at DayaBayrdquo Chinese Physics C vol 37 Article ID 011001 21 pages 2013
[73] J K Ahn S Chebotaryov J H Choi et al ldquoObservationof reactor electron antineutrinos disappearance in the RENOexperimentrdquo Physical Review Letters vol 108 Article ID 1918026 pages 2012
[74] Y Abe C Aberle J C dos Anjos et al ldquoReactor electronantineutrino disappearance in the Double Chooz experimentrdquoPhysical Review D vol 86 Article ID 052008 2012
[75] K Abe N Abgrall H Aihara et al ldquoEvidence of electronneutrino appearance in a muon neutrino beamrdquo PhysicalReview D vol 88 no 3 Article ID 032002 41 pages 2013
[76] A Schreckenberger Electron neutrino and antineutrino appear-ance in the MINOS detector [PhD thesis] University of Min-nesota Minneapolis Minn USA 2013
[77] D J Koskinen MINOS sterile neutrino search [PhD thesis]University College London London UK 2009
[78] M Apollonio A Baldini C Bemporad et al ldquoSearch forneutrino oscillations on a long base-line at the CHOOZ nuclearpower stationrdquoTheEuropean Physical Journal C vol 27 pp 331ndash374 2003
[79] G Tzanankos M Bishai M Diwan et alMINOS+ a proposalto FNAL to run MINOS with the medium energy NuMI beam[PhD thesis] University of Athens Athens Greece 2011
[80] A Aguilar L B Auerbach R L Burman et al ldquoEvidence forneutrino oscillations from the observation of ]
119890e appearance
in a ]120583beamrdquo Physical Review D vol 64 Article ID 112007 22
pages 2001[81] A A Aguilar-Arevalo C E Anderson S J Brice et al ldquoSearch
for electron antineutrino appearance at the Δ119898 sim 1 eV2 ScalerdquoPhysical Review Letters vol 103 no 11 Article ID 111801 2009
[82] A A Aguilar-Arevalo C E Anderson A O Bazarko et alldquoImproved search for V
120583rarr V119890oscillations in the MiniBooNE
experimentrdquo Physical Review Letter vol 110 no 10 Article ID161801 2013
[83] GMentionM Fechner T Lasserre et al ldquoReactor antineutrinoanomalyrdquo Physical Review D vol 83 Article ID 073006 20pages 2011
18 Advances in High Energy Physics
[84] KNAbazajianMAAcero S KAgarwalla et al ldquoLight sterileneutrinos a white paperrdquo httparxivorgabs12045379
[85] B Achkar R Aleksan M Avenier et al ldquoSearch for neutrinooscillations at 15 40 and 95meters from a nuclear power reactorat Bugeyrdquo Nuclear Physics B vol 434 no 3 pp 503ndash532 1995
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
High Energy PhysicsAdvances in
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
FluidsJournal of
Atomic and Molecular Physics
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in Condensed Matter Physics
OpticsInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
AstronomyAdvances in
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Superconductivity
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Statistical MechanicsInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
GravityJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
AstrophysicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Physics Research International
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Solid State PhysicsJournal of
Computational Methods in Physics
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Soft MatterJournal of
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AerodynamicsJournal of
Volume 2014
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PhotonicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Biophysics
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
ThermodynamicsJournal of
12 Advances in High Energy Physics
Reconstructed energy (GeV)
Reconstructed energy (GeV)
Even
ts
30
0
10
20
Even
ts
30
0
10
20
Even
ts
30
0
10
20
2 4 6 8
2 4 6 8
Reconstructed energy (GeV)2 4 6 8
06 lt 120572LEM lt 07
MINOS far detector data
07 lt 120572LEM lt 08
120572LEM gt 08
mode
mode
mode
e CC signal
e CC signalBackgroundData
(a)
Even
ts
Reconstructed energy (GeV)2 4 6 8
Reconstructed energy (GeV)2 4 6 8
Reconstructed energy (GeV)2 4 6 8
06 lt 120572LEM lt 07
MINOS far detector data
Merged for fit
07 lt 120572LEM lt 08
120572LEM gt 08
mode
mode
mode
8
6
4
2
0
Even
ts
8
6
4
2
0
Even
ts
8
6
4
2
0
e CC signal
e CC signalBackgroundData
5ndash8GeV bins
(b)
Figure 16 The CC ]119890(a) and ]
119890(b) candidate events selected in the FD compared to the expectation without any ]
119890appearance (red) and
with the best fit for 12057913(purple) The events are divided into bins of the library event matching discriminant variable
Advances in High Energy Physics 13
20
15
10
05
000 01 02 03 04
2sin2(212057913)sin212057923
Δm2 gt 0
sin
120575(120587)
(a)
20
15
10
05
000 01 02 03 04
2sin2(212057913)sin212057923
MINOS best fit 12057923 lt 1205874
MINOS best fit 12057923 gt 1205874
Δm2 lt 0
MINOS
106 times 1020 POT -mode33 times 1020 POT -mode
68 CL 12057923 lt 1205874
90 CL 12057923 lt 1205874
120575(120587)
(b)
Figure 17 The allowed regions for 2sin2(212057913)sin2(120579
23)
120575(120587)
Δm2 gt 0 12057923 gt 1205874
Δm2 gt 0 12057923 lt 1205874
Δm2 lt 0 12057923 gt 1205874Δm2 lt 0 12057923 lt 1205874
3
2
1
00 1 1505 2
MINOS
90 CL
68 CL
minus2Δ
(L)
ln
Figure 18 The values of likelihood 119871 by which various values oftheCP violating parameter 120575 the mass hierarchy and the octant of12057923are disfavouredThis analysis uses MINOS data and information
from reactor neutrino measurements of 12057913[72ndash74]
physics and has finished taking data with the low energybeam for which it was designed However the experimentwill continue taking data and producing new results for thenext few years as MINOS+ [79] The NuMI beam is being
20
2018161410 12
Far detector data
Even
ts (G
eV)
00 2 4 6 8
40
60
80
100
120
140
12057913 = 0∘
12057913 = 115∘ 120575 = 120587 Δm232 gt 0
120583 CC background|Δm2
32| = 232 times 10minus3eV2
Ereco (GeV)
sin2212057923 = 1
Figure 19 The black dots show the energy spectrum of NCinteractions observed in the far detector The red lines show theexpectation in the case of no sterile neutrinos and 120579
13= 0 the blue
dashed line shows the same expectation with 12057913= 115
∘
upgraded to a higher energy and intensity for the NO]Aexperiment the far detector of which will sit 14 mrad offaxisNO]A will receive a narrow-band beam peaking at around2GeV which is ideal for searching for ]
119890appearance since
the background seen in MINOS from NC interactions ofhigh energy neutrinos will be heavily reduced Figure 20shows that the MINOS FD will see an intense ]
120583beam
14 Advances in High Energy Physics
1000
500
00 5 10 15 20
E (GeV)
MINOS+NOAMINOS
Preliminary
Simulated beam54 kton 6 times 1020 POT
120583CC
even
ts (G
eV)
Figure 20 The ]120583energy spectrum that will be observed by the
MINOS+ FD compared to the spectra observed by MINOS andNO]A
peaking at around 7GeV In this configuration MINOS+ willobserve around 4000 CC ]
120583interactions in the FD each
year unprecedented statistics for a long-baseline oscillationexperimentThis will offer a unique high precision test of thethree-flavour oscillation paradigm
MINOS+ will be able to make a very sensitive searchfor the sterile neutrinos suggested by the LSND [80] andMiniBooNE [81 82] data and by some interpretations ofreactor neutrino data [83] This search will cover more thanthree orders of magnitude in the mass splitting between thesterile and active neutrinos The signal that MINOS+ willsearch for is illustrated in Figure 21 Figure 21(a) illustratesthe increase in statistical precision thatMINOS+will provideon the ratio of the observed CC ]
120583interaction rate to
that expected without oscillations Figure 21(b) shows howthis ratio is modified if a sterile neutrino exists and mixeswith the active neutrinos an additional deficit of muonneutrino interactions occurs in the higher energy region ofthe spectrum In the model assumed here which introducesa single sterile neutrino state three new mixing angles areintroduced 120579
14 12057924 and 120579
34 An additional mass splitting
Δ1198982
43is also introduced The position in energy of the
additional deficit is governed by the value of the new masssplittingThemagnitude of the additional deficit in the CC ]
120583
interaction rate is governed primarily by the size of 12057924 this is
in comparison to short-baseline searches for ]119890disappearance
from reactors which are governed by 12057914and searches for ]
119890
appearance in ]120583beamswhich are governed by a combination
of 12057914
and 12057924 A detailed explanation of the global effort to
search for sterile neutrinos can be found in [84]The sensitivity of the MINOS+ experiment when com-
bined with the Bugey reactor neutrino data [85] is shown in
MINOS+ simulation
MINOS 1071 times 1021 POT06 times 1021 POT12 times 1021 POT18 times 1021 POT
120583su
rviv
al p
roba
bilit
y
Neutrino energy (GeV)0 5 10 15
15
1
05
0
(a)
P(
120583rarr
120583)
No sterile neutrinosΔm2
43 = 2 times 10minus2eV2 sin2(212057924) = 02
0 5 10 15 20
1
0
18
06
04
02
Neutrino energy (GeV)
(b)
Figure 21 (a) The black points show the ratio of the observed ]120583
energy spectrum to the expectation in the case of no oscillation inthe neutrino-dominated beam of MINOS The blue region showsthe statistical precision expected from MINOS+ (b) The black lineshows the muon neutrino survival probability in the case of nosterile neutrinos the red line shows how the probability would bemodified by the addition of mixing with a sterile neutrino
Figure 22 MINOS+ has the potential to rule out much of theLSND allowed region MINOS+ will begin taking data in thelate summer of 2013 and will continue taking data for at leasttwo years (Figure 22 assumes two years of data taking with aneutrino-dominated beam)
8 Conclusion
The MINOS experiment was conceived at a time when neu-trino oscillation had only recently been confirmed as thesolution to the problem of neutrino flavour change It has
Advances in High Energy Physics 15
Δm
2
10minus210minus2
10minus1
10minus1
10minus310minus4 1
1
10
102
LSND 90 CLLSND 99 CLKarmen2 90 CLBugey 90 CLlowast
MiniBooNE 90 CLMiniBooNE 99 CLMINOS+ and Bugeycombination 90 CL
sin22120579120583e
lowastGLoBES 2012 fit with new reactor fluxescourtesy of P Huber
Figure 22 The sensitivity of MINOS+ to the existence of sterileneutrinos when combined with data from the Bugey [85] reactorneutrino experiment Δ1198982 is the splitting between the three knownneutrino mass states and a new fourth state 120579
120583119890is the mixing angle
governing ]120583rarr ]119890transitions when a fourth sterile neutrino state
is introduced into the PMNSmixingmatrixThis figure assumes twoyears of MINOS+ running with a neutrino-dominated beam
played a hugely influential role in bringing neutrino oscilla-tion physics into an era of precision measurement MINOSrsquosmeasurement of the largest neutrino mass splitting is themost precise in the world MINOS has made the first directprecision measurement of the corresponding antineutrinoparameters a measurement that promises to remain theworldrsquos most precise for many years And MINOS has playeda role in the discovery of a nonzero value for 120579
13
Now that the value of 12057913is known the neutrino physics
community can move on to determine the neutrino masshierarchy and to search for CP violation in the neutrinosector MINOS has pioneered a number of techniques thatwill be used by future experiments The two-detector setupall important in reducing the impact of systematic uncer-tainties is the design of choice for any new experiment andMINOS has demonstrated methods of using a near detectorto determine the expectation at a far detector MINOS hasperformed the first search for ]
119890appearance in a ]
120583beam
and the first search for ]119890and ]119890appearance with significant
matter effects demonstrating the analysis techniques that willbe used to determine the mass hierarchy and CP violationparameter
In the second half of 2013 MINOS will begin taking dataas the MINOS+ experiment which will make ever more pre-cise tests of the three-flavour neutrino oscillation paradigmand set world-leading limits on the existence of sterileneutrinos This is an exciting future for an experiment thatwith a decade of data taking so far has already created alasting legacy for itself in our understanding of the neutrino
A comparison of themeasured neutrino and antineutrinomass splittings is shown in Figure 14 the difference betweenthe two is constrained to |Δ119898
2| minus |Δ119898
2| = (012
+024
minus026) times
10minus3 eV2
Acknowledgment
The work of the MINOS and MINOS+ collaborations issupported by the US DoE the UK STFC the US NSF theState and University of Minnesota the University of Athensin Greece and Brazilrsquos FAPESP and CNPq The authors aregrateful to the Minnesota Department of Natural Resourcesthe crew of the Soudan Underground Laboratory and thepersonnel of Fermilab for their vital contributions
References
[1] S Wojcicki ldquoLong baseline neutrino oscillation programe inthe United Statesrdquo Nuclear Physics B vol 77 no 1ndash3 pp 182ndash186 1999 Proceedings of the 18th International Conference onNeutrino Physics and Astrophysics (Neutrino rsquo98) TakayamaJapan June 1998
[2] R Davis Jr D S Harmer and K C Hoffman ldquoSearch forneutrinos from the sunrdquo Physical Review Letters vol 20 no 21pp 1205ndash1209 1968
[3] A I Abazov O L Anosov E L Faizov et al ldquoSearch forneutrinos from sun using the reactionGa-71 (electron-neutrinoe-) Ge-71rdquo Physical Review Letters vol 67 pp 3332ndash3335 1991
[4] P Anselmann W Hampel G Heusser et al ldquoSolar neutrinosobserved by GALLEX at gran sassordquo Physics Letters B vol 285no 4 pp 376ndash389 1992
[5] M Aglietta G Battistoni E Bellotti et al ldquoExperimentalstudy of atmospheric neutrino flux in the NUSEX experimentrdquoEurophysics Letters vol 8 no 7 article 611 1989
[6] K S Hirata ldquoObservation of a small atmospheric V120583V119890ratio in
Kamiokanderdquo Physics Letters B vol 280 no 1-2 pp 146ndash1521992
[7] R Becker-Szendy C B Bratton D Casper et al ldquoElectron-and muon-neutrino content of the atmospheric fluxrdquo PhysicalReview D vol 46 pp 3720ndash3724 1992
[8] K Daum W Rhode P Bareyre et al ldquoDetermination ofthe atmospheric neutrino spectra with the frejus detectorrdquoZeitschrift fur Physik C vol 66 no 3 pp 417ndash428 1995
[9] S Ahlen M Ambrosio R Antolini and G Auriemma ldquoAtmo-spheric neutrino flux measurement using upgoing muonsrdquoPhysics Letters B vol 357 no 3 pp 481ndash486 1995
[10] WMAllison G J Alner D S Ayres et al ldquoMeasurement of theatmospheric neutrino flavour composition in Soudan 2rdquoPhysicsLetters B vol 391 no 3-4 pp 491ndash500 1997
16 Advances in High Energy Physics
[11] Y Fukuda T Hayakawa E Ichihara et al ldquoEvidence foroscillation of atmospheric neutrinosrdquo Physical Review Lettersvol 81 no 8 pp 1562ndash1567 1998
[12] Q R Ahmad R C Allen T C Andersen et al ldquoMeasurementof charged current interactions produced by solar neutrinos atthe sudbury neutrino observatoryrdquo Physical Review Letters vol87 Article ID 071301 2001
[13] Q R Ahmad R C Allen T C Andersen et al ldquoDirect evidencefor neutrino flavor transformation from neutral-current inter-actions in the sudbury neutrino observatoryrdquo Physical ReviewLetters vol 89 Article ID 011301 6 pages 2002
[14] B Pontecorvo ldquoInverse beta processes and nonconservation oflepton chargerdquo Journal of Experimental and Theoretical Physicsvol 34 pp 172ndash173 1958
[15] V N Gribov and B Pontecorvo ldquoNeutrino astronomy andlepton chargerdquo Physics Letters B vol 28 pp 493ndash496 1969
[16] Z Maki M Nakagawa and S Sakata ldquoRemarks on the unifiedmodel of elementary particlesrdquo Progress of Theoretical Physicsvol 28 no 5 pp 870ndash880 1962
[17] P Adamson C Andreopoulos D J Auty et al ldquoFirst directobservation of muon antineutrino disappearancerdquo PhysicalReview Letters vol 107 no 2 Article ID 021801 2011
[18] P Adamson D J Auty D S Ayres et al ldquoSearch for thedisappearance of muon antineutrinos in the NuMI neutrinobeamrdquo Physical Review D vol 84 no 7 Article ID 071103 6pages 2011
[19] P Adamson D S Ayres C Backhouse et al ldquoImprovedmeasurement of muon antineutrino disappearance inMINOSrdquoPhysical Review Letters vol 108 no 19 Article ID 191801 5pages 2012
[20] P Adamson I Anghel C Backhouse et al ldquoMeasurementof Neutrino and Antineutrino Oscillations Using Beam andAtmospheric Data in MINOSrdquo Physical Review Letters vol 110no 25 Article ID 251801 6 pages 2013
[21] K Anderson B Bernstein D Boehnlein et al ldquoThe NuMIFacility Technical Design Reportrdquo FERMILAB-DESIGN-1998-01 1998
[22] D G Michael P Adamson T Alexopoulos et al ldquoObservationof muon neutrino disappearance with the MINOS detectors inthe NuMI neutrino beamrdquo Physical Review Letters vol 97 no19 Article ID 191801 6 pages 2006
[23] P Adamson C Andreopoulos K E Arms et al ldquoStudy ofmuon neutrino disappearance using the fermilab main injectorneutrino beamrdquo Physical Review D vol 77 no 7 Article ID072002 34 pages 2008
[24] P Adamson C Andreopoulos K E Arms et al ldquoMeasurementof neutrino oscillations with theMINOS detectors in the NuMIbeamrdquo Physical Review Letters vol 101 no 13 Article ID 1318025 pages 2008
[25] P Adamson C Andreopoulos R Armstrong et al ldquoMea-surement of the neutrino mass splitting and flavor mixing byMINOSrdquo Physical Review Letters vol 106 no 18 Article ID181801 6 pages 2011
[26] P Adamson C Andreopoulos K E Arms et al ldquoSearch formuon-neutrino to electron-neutrino transitions in MINOSrdquoPhysical Review Letters vol 103 no 26 Article ID 261802 5pages 2009
[27] PAdamsonCAndreopoulosD J Auty et al ldquoNew constraintsonmuon-neutrino to electron-neutrino transitions inMINOSrdquoPhysical ReviewD vol 82 no 5 Article ID 051102 6 pages 2010
[28] P Adamson D J Auty D S Ayres et al ldquoImproved search formuon-neutrino to electron-neutrino oscillations in MINOSrdquoPhysical Review Letters vol 107 no 18 Article ID 181802 6pages 2011
[29] P Adamson I Anghel C Backhouse et al ldquoElectron neutrinoand antineutrino appearance in the full MINOS data samplerdquoPhysical Review Letters vol 110 no 17 Article ID 171801 6 pages2013
[30] P Adamson C Andreopoulos K E Arms et al ldquoSearch foractive neutrino disappearance using neutral-current interac-tions in theMINOS long-baseline experimentrdquo Physical ReviewLetters vol 101 no 22 Article ID 221804 5 pages 2008
[31] P Adamson C Andreopoulos D J Auty et al ldquoSearch for ster-ile neutrino mixing in the MINOS long-baseline experimentrdquoPhysical Review D vol 81 no 5 Article ID 052004 18 pages2010
[32] P Adamson D J Auty D S Ayres et al ldquoActive to sterileneutrino mixing limits from neutral-current interactions inMINOSrdquo Physical Review Letters vol 107 no 1 Article ID011802 5 pages 2011
[33] Z Pavlovic Observation of disappearance of muon neutrinos inthe NuMI beam [PhD thesis] University of Texas at AustinAustin Tex USA 2008
[34] F Ballarini G Battistoni M Campanella et al ldquoThe FLUKAcode an overviewrdquo Journal of Physics vol 41 article 151 2006
[35] S Agostinelli J Allison K Amako et al ldquoGEANT4mdasha sim-ulation toolkitrdquo Nuclear Instruments and Methods in PhysicsResearch A vol 506 no 3 pp 250ndash303 2003
[36] G Battistoni F Cerutti A Fasso et al ldquoThe FLUKA codedescription and benchmarkingrdquo in Proceedings of the HadronicShower Simulation Workshop vol 896 of AIP Conference Pro-ceedings pp 31ndash49 Batavia Ill USA September 2006
[37] D G Michaele P Adamson T Alexopoulos et al ldquoThe mag-netized steel and scintillator calorimeters of the MINOS exper-imentrdquoNuclear Instruments and Methods in Physics Research Avol 596 no 2 pp 190ndash228 2008
[38] I E Stockdale A Bodek F Borcherding N Giokaris et alldquoLimits on muon-neutrino oscillations in the mass range 30 lt9987791198982lt 1000 eV2c4 rdquo Physical Review Letters vol 52 no 16 pp
1384ndash1388 1984[39] F Dydak G J Feldman C Guyot et al ldquoA search for V
120583
oscillations in the9987791198982 range 03ndash90 eV2 rdquo Physics Letters B vol134 no 3-4 pp 281ndash286 1984
[40] F Bergsma J Dorenbosch M Jonker et al ldquoA searchfor oscillations of muon neutrinos in an experiment withLEcong07 kmGeVrdquo Physics Letters B vol 142 no 1-2 pp 103ndash1101984
[41] M H Ahn E Aliu S Andringa et al ldquoMeasurement ofneutrino oscillation by the K2K experimentrdquo Physical ReviewD vol 74 no 7 Article ID 072003 39 pages 2006
[42] P Adamson T Alexopoulos W W M Allison et al ldquoFirstobservations of separated atmospheric V
120583and ]
120583events in the
MINOS detectorrdquo Physical Review D vol 73 no 7 Article ID072002 2006
[43] P Adamson C Andreopoulos K E Arms et al ldquoCharge-separated atmospheric neutrino-inducedmuons in theMINOSfar detectorrdquo Physical ReviewD vol 75 no 9 Article ID 09200314 pages 2007
[44] P Adamson C Backhouse G Barr et al ldquoMeasurements ofatmospheric neutrinos and antineutrinos in the MINOS fardetectorrdquo Physical Review D vol 86 no 5 Article ID 05200720 pages 2012
Advances in High Energy Physics 17
[45] M A Kordosky Hadronic interactions in the MINOS detectors[PhD thesis] University of Texas at Austin Austin Tex USA2004
[46] P L Vahle Electromagnetic interactions in the MINOS detectors[PhD thesis] University of Texas at Austin Austin Tex USA2004
[47] C Backhouse Measuring neutrino oscillation parameters using]120583disappearance inMINOS [PhD thesis] University of Oxford
Oxford UK 2011[48] T M Cover and P E Hart ldquoNearest neighbor pattern classifi-
cationrdquo IEEE Transactions on Information Theory vol 13 no 1pp 21ndash27 1967
[49] R Ospanov A measurement of muon neutrino disappearancewith the MINOS detectors and NuMI beam [PhD thesis]University of Texas at Austin Austin Tex USA 2008
[50] J S Marshall A study of muon neutrino disappearance with theMINOS detectors and the NuMI neutrino beam [PhD thesis]University of Cambridge Cambridge UK 2008
[51] J P OchoaA search formuon neutrino to electron neutrino oscil-lations in the MINOS Experiment [PhD thesis] The CaliforniaInstitute of Technology Pasadena Calif USA 2009
[52] R TonerMeasuring 12057913via muon neutrino to electron neutrino
oscillations in the MINOS experiment [PhD thesis] Universityof Cambridge Cambridge UK 2011
[53] A Holin Electron neutrino appearance in the MINOS experi-ment [PhD thesis] University College London London UK2010
[54] J Boehm Measurement of electron neutrino appearance withthe MINOS experiment [PhD thesis] Harvard UniversityCambridge Mass USA 2009
[55] G Tinti Sterile neutrino oscillations in MINOS and hadronproduction in pC collisions [PhD thesis] University of OxfordOxford UK 2010
[56] J J EvansMeasuring antineutrino oscillations with the MINOSexperiment [PhD thesis] University of Oxford Oxford UK2008
[57] S J ColemanAmeasurement of neutrino oscillations withmuonneutrinos in the MINOS experiment [PhD thesis] College ofWilliam ampMary Williamsburg Va USA 2011
[58] J S Mitchell Measuring ]120583disappearance with the MINOS
experiment [PhD thesis] University of Cambridge CambridgeUK 2011
[59] A McGowan Observation of deficit in NuMI neutrino-inducedrock and non-fiducial muons in MINOS far detector andmeasurement of neutrino oscillation parameters [PhD thesis]University of Minnesota Minneapolis Minn USA 2007
[60] M StraitMeasurement of neutrino oscillation parameters usinganti-fiducial charged current events in MINOS [PhD thesis]University of Minnesota Minneapolis Minn USA 2010
[61] Y Itow ldquoAtmospheric neutrinosmdashresults from running exper-imentsrdquo in Proceedings of the 25th International Conference onNeutrino Physics and Astrophysics (Neutrino rsquo12) Kyoto JapanJune 2012
[62] K Abe N Abgrall Y Ajima et al ldquoFirst muon-neutrinodisappearance study with an off-axis beamrdquo Physical Review Dvol 85 no 3 Article ID 031103 8 pages 2012
[63] K Nakamura ldquoReview of particle physicsrdquo Journal of Physics Gvol 37 Article ID 075021 2010
[64] L Wolfenstein ldquoNeutrino oscillations in matterrdquo PhysicalReview D vol 17 no 9 pp 2369ndash2374 1978
[65] J W F Valle ldquoResonant oscillations of massless neutrinos inmatterrdquo Physics Letters B vol 199 no 3 pp 432ndash436 1987
[66] M C Gonzalez-Garcia M M Guzzo P I Krastev et alldquoAtmospheric neutrino observations and flavor changing inter-actionsrdquo Physical Review Letters vol 82 no 16 pp 3202ndash32051999
[67] A Friedland C Lunardini and M Maltoni ldquoAtmosphericneutrinos as probes of neutrino-matter interactionsrdquo PhysicalReview D vol 70 no 11 Article ID 111301 2004
[68] Z IsvanAntineutrino oscillations and a Search for non-standardInteractions with the MINOS [PhD thesis] University of Pitts-burgh Pittsburgh Pa USA 2012
[69] W A Mann D Cherdack W Musial and T Kafka ldquoApparentmultiple 998779119898
32
2 in ]120583and V
120583survival oscillations from nonstan-
dard interactionmatter effectrdquo Physical Review D vol 82 no 11Article ID 113010 8 pages 2010
[70] J Kopp P A N Machado and S J Parke ldquoInterpretation ofMINOS data in terms of nonstandard neutrino interactionsrdquoPhysical Review D vol 82 no 11 Article ID 113002 12 pages2010
[71] J A B Coelho Investigacao de mecanismos alternativos aoscilacao de neutrinos no experimentos MINOS [PhD thesis]Universidade Estadual de Campinas Sao Paulo Brazil 2012
[72] F P An Q An J Z Bai A B Balantekin et al ldquoImprovedmeasurement of electron antineutrino disappearance at DayaBayrdquo Chinese Physics C vol 37 Article ID 011001 21 pages 2013
[73] J K Ahn S Chebotaryov J H Choi et al ldquoObservationof reactor electron antineutrinos disappearance in the RENOexperimentrdquo Physical Review Letters vol 108 Article ID 1918026 pages 2012
[74] Y Abe C Aberle J C dos Anjos et al ldquoReactor electronantineutrino disappearance in the Double Chooz experimentrdquoPhysical Review D vol 86 Article ID 052008 2012
[75] K Abe N Abgrall H Aihara et al ldquoEvidence of electronneutrino appearance in a muon neutrino beamrdquo PhysicalReview D vol 88 no 3 Article ID 032002 41 pages 2013
[76] A Schreckenberger Electron neutrino and antineutrino appear-ance in the MINOS detector [PhD thesis] University of Min-nesota Minneapolis Minn USA 2013
[77] D J Koskinen MINOS sterile neutrino search [PhD thesis]University College London London UK 2009
[78] M Apollonio A Baldini C Bemporad et al ldquoSearch forneutrino oscillations on a long base-line at the CHOOZ nuclearpower stationrdquoTheEuropean Physical Journal C vol 27 pp 331ndash374 2003
[79] G Tzanankos M Bishai M Diwan et alMINOS+ a proposalto FNAL to run MINOS with the medium energy NuMI beam[PhD thesis] University of Athens Athens Greece 2011
[80] A Aguilar L B Auerbach R L Burman et al ldquoEvidence forneutrino oscillations from the observation of ]
119890e appearance
in a ]120583beamrdquo Physical Review D vol 64 Article ID 112007 22
pages 2001[81] A A Aguilar-Arevalo C E Anderson S J Brice et al ldquoSearch
for electron antineutrino appearance at the Δ119898 sim 1 eV2 ScalerdquoPhysical Review Letters vol 103 no 11 Article ID 111801 2009
[82] A A Aguilar-Arevalo C E Anderson A O Bazarko et alldquoImproved search for V
120583rarr V119890oscillations in the MiniBooNE
experimentrdquo Physical Review Letter vol 110 no 10 Article ID161801 2013
[83] GMentionM Fechner T Lasserre et al ldquoReactor antineutrinoanomalyrdquo Physical Review D vol 83 Article ID 073006 20pages 2011
18 Advances in High Energy Physics
[84] KNAbazajianMAAcero S KAgarwalla et al ldquoLight sterileneutrinos a white paperrdquo httparxivorgabs12045379
[85] B Achkar R Aleksan M Avenier et al ldquoSearch for neutrinooscillations at 15 40 and 95meters from a nuclear power reactorat Bugeyrdquo Nuclear Physics B vol 434 no 3 pp 503ndash532 1995
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
High Energy PhysicsAdvances in
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
FluidsJournal of
Atomic and Molecular Physics
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in Condensed Matter Physics
OpticsInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
AstronomyAdvances in
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Superconductivity
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Statistical MechanicsInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
GravityJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
AstrophysicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Physics Research International
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Solid State PhysicsJournal of
Computational Methods in Physics
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Soft MatterJournal of
Hindawi Publishing Corporationhttpwwwhindawicom
AerodynamicsJournal of
Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
PhotonicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Biophysics
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
ThermodynamicsJournal of
Advances in High Energy Physics 13
20
15
10
05
000 01 02 03 04
2sin2(212057913)sin212057923
Δm2 gt 0
sin
120575(120587)
(a)
20
15
10
05
000 01 02 03 04
2sin2(212057913)sin212057923
MINOS best fit 12057923 lt 1205874
MINOS best fit 12057923 gt 1205874
Δm2 lt 0
MINOS
106 times 1020 POT -mode33 times 1020 POT -mode
68 CL 12057923 lt 1205874
90 CL 12057923 lt 1205874
120575(120587)
(b)
Figure 17 The allowed regions for 2sin2(212057913)sin2(120579
23)
120575(120587)
Δm2 gt 0 12057923 gt 1205874
Δm2 gt 0 12057923 lt 1205874
Δm2 lt 0 12057923 gt 1205874Δm2 lt 0 12057923 lt 1205874
3
2
1
00 1 1505 2
MINOS
90 CL
68 CL
minus2Δ
(L)
ln
Figure 18 The values of likelihood 119871 by which various values oftheCP violating parameter 120575 the mass hierarchy and the octant of12057923are disfavouredThis analysis uses MINOS data and information
from reactor neutrino measurements of 12057913[72ndash74]
physics and has finished taking data with the low energybeam for which it was designed However the experimentwill continue taking data and producing new results for thenext few years as MINOS+ [79] The NuMI beam is being
20
2018161410 12
Far detector data
Even
ts (G
eV)
00 2 4 6 8
40
60
80
100
120
140
12057913 = 0∘
12057913 = 115∘ 120575 = 120587 Δm232 gt 0
120583 CC background|Δm2
32| = 232 times 10minus3eV2
Ereco (GeV)
sin2212057923 = 1
Figure 19 The black dots show the energy spectrum of NCinteractions observed in the far detector The red lines show theexpectation in the case of no sterile neutrinos and 120579
13= 0 the blue
dashed line shows the same expectation with 12057913= 115
∘
upgraded to a higher energy and intensity for the NO]Aexperiment the far detector of which will sit 14 mrad offaxisNO]A will receive a narrow-band beam peaking at around2GeV which is ideal for searching for ]
119890appearance since
the background seen in MINOS from NC interactions ofhigh energy neutrinos will be heavily reduced Figure 20shows that the MINOS FD will see an intense ]
120583beam
14 Advances in High Energy Physics
1000
500
00 5 10 15 20
E (GeV)
MINOS+NOAMINOS
Preliminary
Simulated beam54 kton 6 times 1020 POT
120583CC
even
ts (G
eV)
Figure 20 The ]120583energy spectrum that will be observed by the
MINOS+ FD compared to the spectra observed by MINOS andNO]A
peaking at around 7GeV In this configuration MINOS+ willobserve around 4000 CC ]
120583interactions in the FD each
year unprecedented statistics for a long-baseline oscillationexperimentThis will offer a unique high precision test of thethree-flavour oscillation paradigm
MINOS+ will be able to make a very sensitive searchfor the sterile neutrinos suggested by the LSND [80] andMiniBooNE [81 82] data and by some interpretations ofreactor neutrino data [83] This search will cover more thanthree orders of magnitude in the mass splitting between thesterile and active neutrinos The signal that MINOS+ willsearch for is illustrated in Figure 21 Figure 21(a) illustratesthe increase in statistical precision thatMINOS+will provideon the ratio of the observed CC ]
120583interaction rate to
that expected without oscillations Figure 21(b) shows howthis ratio is modified if a sterile neutrino exists and mixeswith the active neutrinos an additional deficit of muonneutrino interactions occurs in the higher energy region ofthe spectrum In the model assumed here which introducesa single sterile neutrino state three new mixing angles areintroduced 120579
14 12057924 and 120579
34 An additional mass splitting
Δ1198982
43is also introduced The position in energy of the
additional deficit is governed by the value of the new masssplittingThemagnitude of the additional deficit in the CC ]
120583
interaction rate is governed primarily by the size of 12057924 this is
in comparison to short-baseline searches for ]119890disappearance
from reactors which are governed by 12057914and searches for ]
119890
appearance in ]120583beamswhich are governed by a combination
of 12057914
and 12057924 A detailed explanation of the global effort to
search for sterile neutrinos can be found in [84]The sensitivity of the MINOS+ experiment when com-
bined with the Bugey reactor neutrino data [85] is shown in
MINOS+ simulation
MINOS 1071 times 1021 POT06 times 1021 POT12 times 1021 POT18 times 1021 POT
120583su
rviv
al p
roba
bilit
y
Neutrino energy (GeV)0 5 10 15
15
1
05
0
(a)
P(
120583rarr
120583)
No sterile neutrinosΔm2
43 = 2 times 10minus2eV2 sin2(212057924) = 02
0 5 10 15 20
1
0
18
06
04
02
Neutrino energy (GeV)
(b)
Figure 21 (a) The black points show the ratio of the observed ]120583
energy spectrum to the expectation in the case of no oscillation inthe neutrino-dominated beam of MINOS The blue region showsthe statistical precision expected from MINOS+ (b) The black lineshows the muon neutrino survival probability in the case of nosterile neutrinos the red line shows how the probability would bemodified by the addition of mixing with a sterile neutrino
Figure 22 MINOS+ has the potential to rule out much of theLSND allowed region MINOS+ will begin taking data in thelate summer of 2013 and will continue taking data for at leasttwo years (Figure 22 assumes two years of data taking with aneutrino-dominated beam)
8 Conclusion
The MINOS experiment was conceived at a time when neu-trino oscillation had only recently been confirmed as thesolution to the problem of neutrino flavour change It has
Advances in High Energy Physics 15
Δm
2
10minus210minus2
10minus1
10minus1
10minus310minus4 1
1
10
102
LSND 90 CLLSND 99 CLKarmen2 90 CLBugey 90 CLlowast
MiniBooNE 90 CLMiniBooNE 99 CLMINOS+ and Bugeycombination 90 CL
sin22120579120583e
lowastGLoBES 2012 fit with new reactor fluxescourtesy of P Huber
Figure 22 The sensitivity of MINOS+ to the existence of sterileneutrinos when combined with data from the Bugey [85] reactorneutrino experiment Δ1198982 is the splitting between the three knownneutrino mass states and a new fourth state 120579
120583119890is the mixing angle
governing ]120583rarr ]119890transitions when a fourth sterile neutrino state
is introduced into the PMNSmixingmatrixThis figure assumes twoyears of MINOS+ running with a neutrino-dominated beam
played a hugely influential role in bringing neutrino oscilla-tion physics into an era of precision measurement MINOSrsquosmeasurement of the largest neutrino mass splitting is themost precise in the world MINOS has made the first directprecision measurement of the corresponding antineutrinoparameters a measurement that promises to remain theworldrsquos most precise for many years And MINOS has playeda role in the discovery of a nonzero value for 120579
13
Now that the value of 12057913is known the neutrino physics
community can move on to determine the neutrino masshierarchy and to search for CP violation in the neutrinosector MINOS has pioneered a number of techniques thatwill be used by future experiments The two-detector setupall important in reducing the impact of systematic uncer-tainties is the design of choice for any new experiment andMINOS has demonstrated methods of using a near detectorto determine the expectation at a far detector MINOS hasperformed the first search for ]
119890appearance in a ]
120583beam
and the first search for ]119890and ]119890appearance with significant
matter effects demonstrating the analysis techniques that willbe used to determine the mass hierarchy and CP violationparameter
In the second half of 2013 MINOS will begin taking dataas the MINOS+ experiment which will make ever more pre-cise tests of the three-flavour neutrino oscillation paradigmand set world-leading limits on the existence of sterileneutrinos This is an exciting future for an experiment thatwith a decade of data taking so far has already created alasting legacy for itself in our understanding of the neutrino
A comparison of themeasured neutrino and antineutrinomass splittings is shown in Figure 14 the difference betweenthe two is constrained to |Δ119898
2| minus |Δ119898
2| = (012
+024
minus026) times
10minus3 eV2
Acknowledgment
The work of the MINOS and MINOS+ collaborations issupported by the US DoE the UK STFC the US NSF theState and University of Minnesota the University of Athensin Greece and Brazilrsquos FAPESP and CNPq The authors aregrateful to the Minnesota Department of Natural Resourcesthe crew of the Soudan Underground Laboratory and thepersonnel of Fermilab for their vital contributions
References
[1] S Wojcicki ldquoLong baseline neutrino oscillation programe inthe United Statesrdquo Nuclear Physics B vol 77 no 1ndash3 pp 182ndash186 1999 Proceedings of the 18th International Conference onNeutrino Physics and Astrophysics (Neutrino rsquo98) TakayamaJapan June 1998
[2] R Davis Jr D S Harmer and K C Hoffman ldquoSearch forneutrinos from the sunrdquo Physical Review Letters vol 20 no 21pp 1205ndash1209 1968
[3] A I Abazov O L Anosov E L Faizov et al ldquoSearch forneutrinos from sun using the reactionGa-71 (electron-neutrinoe-) Ge-71rdquo Physical Review Letters vol 67 pp 3332ndash3335 1991
[4] P Anselmann W Hampel G Heusser et al ldquoSolar neutrinosobserved by GALLEX at gran sassordquo Physics Letters B vol 285no 4 pp 376ndash389 1992
[5] M Aglietta G Battistoni E Bellotti et al ldquoExperimentalstudy of atmospheric neutrino flux in the NUSEX experimentrdquoEurophysics Letters vol 8 no 7 article 611 1989
[6] K S Hirata ldquoObservation of a small atmospheric V120583V119890ratio in
Kamiokanderdquo Physics Letters B vol 280 no 1-2 pp 146ndash1521992
[7] R Becker-Szendy C B Bratton D Casper et al ldquoElectron-and muon-neutrino content of the atmospheric fluxrdquo PhysicalReview D vol 46 pp 3720ndash3724 1992
[8] K Daum W Rhode P Bareyre et al ldquoDetermination ofthe atmospheric neutrino spectra with the frejus detectorrdquoZeitschrift fur Physik C vol 66 no 3 pp 417ndash428 1995
[9] S Ahlen M Ambrosio R Antolini and G Auriemma ldquoAtmo-spheric neutrino flux measurement using upgoing muonsrdquoPhysics Letters B vol 357 no 3 pp 481ndash486 1995
[10] WMAllison G J Alner D S Ayres et al ldquoMeasurement of theatmospheric neutrino flavour composition in Soudan 2rdquoPhysicsLetters B vol 391 no 3-4 pp 491ndash500 1997
16 Advances in High Energy Physics
[11] Y Fukuda T Hayakawa E Ichihara et al ldquoEvidence foroscillation of atmospheric neutrinosrdquo Physical Review Lettersvol 81 no 8 pp 1562ndash1567 1998
[12] Q R Ahmad R C Allen T C Andersen et al ldquoMeasurementof charged current interactions produced by solar neutrinos atthe sudbury neutrino observatoryrdquo Physical Review Letters vol87 Article ID 071301 2001
[13] Q R Ahmad R C Allen T C Andersen et al ldquoDirect evidencefor neutrino flavor transformation from neutral-current inter-actions in the sudbury neutrino observatoryrdquo Physical ReviewLetters vol 89 Article ID 011301 6 pages 2002
[14] B Pontecorvo ldquoInverse beta processes and nonconservation oflepton chargerdquo Journal of Experimental and Theoretical Physicsvol 34 pp 172ndash173 1958
[15] V N Gribov and B Pontecorvo ldquoNeutrino astronomy andlepton chargerdquo Physics Letters B vol 28 pp 493ndash496 1969
[16] Z Maki M Nakagawa and S Sakata ldquoRemarks on the unifiedmodel of elementary particlesrdquo Progress of Theoretical Physicsvol 28 no 5 pp 870ndash880 1962
[17] P Adamson C Andreopoulos D J Auty et al ldquoFirst directobservation of muon antineutrino disappearancerdquo PhysicalReview Letters vol 107 no 2 Article ID 021801 2011
[18] P Adamson D J Auty D S Ayres et al ldquoSearch for thedisappearance of muon antineutrinos in the NuMI neutrinobeamrdquo Physical Review D vol 84 no 7 Article ID 071103 6pages 2011
[19] P Adamson D S Ayres C Backhouse et al ldquoImprovedmeasurement of muon antineutrino disappearance inMINOSrdquoPhysical Review Letters vol 108 no 19 Article ID 191801 5pages 2012
[20] P Adamson I Anghel C Backhouse et al ldquoMeasurementof Neutrino and Antineutrino Oscillations Using Beam andAtmospheric Data in MINOSrdquo Physical Review Letters vol 110no 25 Article ID 251801 6 pages 2013
[21] K Anderson B Bernstein D Boehnlein et al ldquoThe NuMIFacility Technical Design Reportrdquo FERMILAB-DESIGN-1998-01 1998
[22] D G Michael P Adamson T Alexopoulos et al ldquoObservationof muon neutrino disappearance with the MINOS detectors inthe NuMI neutrino beamrdquo Physical Review Letters vol 97 no19 Article ID 191801 6 pages 2006
[23] P Adamson C Andreopoulos K E Arms et al ldquoStudy ofmuon neutrino disappearance using the fermilab main injectorneutrino beamrdquo Physical Review D vol 77 no 7 Article ID072002 34 pages 2008
[24] P Adamson C Andreopoulos K E Arms et al ldquoMeasurementof neutrino oscillations with theMINOS detectors in the NuMIbeamrdquo Physical Review Letters vol 101 no 13 Article ID 1318025 pages 2008
[25] P Adamson C Andreopoulos R Armstrong et al ldquoMea-surement of the neutrino mass splitting and flavor mixing byMINOSrdquo Physical Review Letters vol 106 no 18 Article ID181801 6 pages 2011
[26] P Adamson C Andreopoulos K E Arms et al ldquoSearch formuon-neutrino to electron-neutrino transitions in MINOSrdquoPhysical Review Letters vol 103 no 26 Article ID 261802 5pages 2009
[27] PAdamsonCAndreopoulosD J Auty et al ldquoNew constraintsonmuon-neutrino to electron-neutrino transitions inMINOSrdquoPhysical ReviewD vol 82 no 5 Article ID 051102 6 pages 2010
[28] P Adamson D J Auty D S Ayres et al ldquoImproved search formuon-neutrino to electron-neutrino oscillations in MINOSrdquoPhysical Review Letters vol 107 no 18 Article ID 181802 6pages 2011
[29] P Adamson I Anghel C Backhouse et al ldquoElectron neutrinoand antineutrino appearance in the full MINOS data samplerdquoPhysical Review Letters vol 110 no 17 Article ID 171801 6 pages2013
[30] P Adamson C Andreopoulos K E Arms et al ldquoSearch foractive neutrino disappearance using neutral-current interac-tions in theMINOS long-baseline experimentrdquo Physical ReviewLetters vol 101 no 22 Article ID 221804 5 pages 2008
[31] P Adamson C Andreopoulos D J Auty et al ldquoSearch for ster-ile neutrino mixing in the MINOS long-baseline experimentrdquoPhysical Review D vol 81 no 5 Article ID 052004 18 pages2010
[32] P Adamson D J Auty D S Ayres et al ldquoActive to sterileneutrino mixing limits from neutral-current interactions inMINOSrdquo Physical Review Letters vol 107 no 1 Article ID011802 5 pages 2011
[33] Z Pavlovic Observation of disappearance of muon neutrinos inthe NuMI beam [PhD thesis] University of Texas at AustinAustin Tex USA 2008
[34] F Ballarini G Battistoni M Campanella et al ldquoThe FLUKAcode an overviewrdquo Journal of Physics vol 41 article 151 2006
[35] S Agostinelli J Allison K Amako et al ldquoGEANT4mdasha sim-ulation toolkitrdquo Nuclear Instruments and Methods in PhysicsResearch A vol 506 no 3 pp 250ndash303 2003
[36] G Battistoni F Cerutti A Fasso et al ldquoThe FLUKA codedescription and benchmarkingrdquo in Proceedings of the HadronicShower Simulation Workshop vol 896 of AIP Conference Pro-ceedings pp 31ndash49 Batavia Ill USA September 2006
[37] D G Michaele P Adamson T Alexopoulos et al ldquoThe mag-netized steel and scintillator calorimeters of the MINOS exper-imentrdquoNuclear Instruments and Methods in Physics Research Avol 596 no 2 pp 190ndash228 2008
[38] I E Stockdale A Bodek F Borcherding N Giokaris et alldquoLimits on muon-neutrino oscillations in the mass range 30 lt9987791198982lt 1000 eV2c4 rdquo Physical Review Letters vol 52 no 16 pp
1384ndash1388 1984[39] F Dydak G J Feldman C Guyot et al ldquoA search for V
120583
oscillations in the9987791198982 range 03ndash90 eV2 rdquo Physics Letters B vol134 no 3-4 pp 281ndash286 1984
[40] F Bergsma J Dorenbosch M Jonker et al ldquoA searchfor oscillations of muon neutrinos in an experiment withLEcong07 kmGeVrdquo Physics Letters B vol 142 no 1-2 pp 103ndash1101984
[41] M H Ahn E Aliu S Andringa et al ldquoMeasurement ofneutrino oscillation by the K2K experimentrdquo Physical ReviewD vol 74 no 7 Article ID 072003 39 pages 2006
[42] P Adamson T Alexopoulos W W M Allison et al ldquoFirstobservations of separated atmospheric V
120583and ]
120583events in the
MINOS detectorrdquo Physical Review D vol 73 no 7 Article ID072002 2006
[43] P Adamson C Andreopoulos K E Arms et al ldquoCharge-separated atmospheric neutrino-inducedmuons in theMINOSfar detectorrdquo Physical ReviewD vol 75 no 9 Article ID 09200314 pages 2007
[44] P Adamson C Backhouse G Barr et al ldquoMeasurements ofatmospheric neutrinos and antineutrinos in the MINOS fardetectorrdquo Physical Review D vol 86 no 5 Article ID 05200720 pages 2012
Advances in High Energy Physics 17
[45] M A Kordosky Hadronic interactions in the MINOS detectors[PhD thesis] University of Texas at Austin Austin Tex USA2004
[46] P L Vahle Electromagnetic interactions in the MINOS detectors[PhD thesis] University of Texas at Austin Austin Tex USA2004
[47] C Backhouse Measuring neutrino oscillation parameters using]120583disappearance inMINOS [PhD thesis] University of Oxford
Oxford UK 2011[48] T M Cover and P E Hart ldquoNearest neighbor pattern classifi-
cationrdquo IEEE Transactions on Information Theory vol 13 no 1pp 21ndash27 1967
[49] R Ospanov A measurement of muon neutrino disappearancewith the MINOS detectors and NuMI beam [PhD thesis]University of Texas at Austin Austin Tex USA 2008
[50] J S Marshall A study of muon neutrino disappearance with theMINOS detectors and the NuMI neutrino beam [PhD thesis]University of Cambridge Cambridge UK 2008
[51] J P OchoaA search formuon neutrino to electron neutrino oscil-lations in the MINOS Experiment [PhD thesis] The CaliforniaInstitute of Technology Pasadena Calif USA 2009
[52] R TonerMeasuring 12057913via muon neutrino to electron neutrino
oscillations in the MINOS experiment [PhD thesis] Universityof Cambridge Cambridge UK 2011
[53] A Holin Electron neutrino appearance in the MINOS experi-ment [PhD thesis] University College London London UK2010
[54] J Boehm Measurement of electron neutrino appearance withthe MINOS experiment [PhD thesis] Harvard UniversityCambridge Mass USA 2009
[55] G Tinti Sterile neutrino oscillations in MINOS and hadronproduction in pC collisions [PhD thesis] University of OxfordOxford UK 2010
[56] J J EvansMeasuring antineutrino oscillations with the MINOSexperiment [PhD thesis] University of Oxford Oxford UK2008
[57] S J ColemanAmeasurement of neutrino oscillations withmuonneutrinos in the MINOS experiment [PhD thesis] College ofWilliam ampMary Williamsburg Va USA 2011
[58] J S Mitchell Measuring ]120583disappearance with the MINOS
experiment [PhD thesis] University of Cambridge CambridgeUK 2011
[59] A McGowan Observation of deficit in NuMI neutrino-inducedrock and non-fiducial muons in MINOS far detector andmeasurement of neutrino oscillation parameters [PhD thesis]University of Minnesota Minneapolis Minn USA 2007
[60] M StraitMeasurement of neutrino oscillation parameters usinganti-fiducial charged current events in MINOS [PhD thesis]University of Minnesota Minneapolis Minn USA 2010
[61] Y Itow ldquoAtmospheric neutrinosmdashresults from running exper-imentsrdquo in Proceedings of the 25th International Conference onNeutrino Physics and Astrophysics (Neutrino rsquo12) Kyoto JapanJune 2012
[62] K Abe N Abgrall Y Ajima et al ldquoFirst muon-neutrinodisappearance study with an off-axis beamrdquo Physical Review Dvol 85 no 3 Article ID 031103 8 pages 2012
[63] K Nakamura ldquoReview of particle physicsrdquo Journal of Physics Gvol 37 Article ID 075021 2010
[64] L Wolfenstein ldquoNeutrino oscillations in matterrdquo PhysicalReview D vol 17 no 9 pp 2369ndash2374 1978
[65] J W F Valle ldquoResonant oscillations of massless neutrinos inmatterrdquo Physics Letters B vol 199 no 3 pp 432ndash436 1987
[66] M C Gonzalez-Garcia M M Guzzo P I Krastev et alldquoAtmospheric neutrino observations and flavor changing inter-actionsrdquo Physical Review Letters vol 82 no 16 pp 3202ndash32051999
[67] A Friedland C Lunardini and M Maltoni ldquoAtmosphericneutrinos as probes of neutrino-matter interactionsrdquo PhysicalReview D vol 70 no 11 Article ID 111301 2004
[68] Z IsvanAntineutrino oscillations and a Search for non-standardInteractions with the MINOS [PhD thesis] University of Pitts-burgh Pittsburgh Pa USA 2012
[69] W A Mann D Cherdack W Musial and T Kafka ldquoApparentmultiple 998779119898
32
2 in ]120583and V
120583survival oscillations from nonstan-
dard interactionmatter effectrdquo Physical Review D vol 82 no 11Article ID 113010 8 pages 2010
[70] J Kopp P A N Machado and S J Parke ldquoInterpretation ofMINOS data in terms of nonstandard neutrino interactionsrdquoPhysical Review D vol 82 no 11 Article ID 113002 12 pages2010
[71] J A B Coelho Investigacao de mecanismos alternativos aoscilacao de neutrinos no experimentos MINOS [PhD thesis]Universidade Estadual de Campinas Sao Paulo Brazil 2012
[72] F P An Q An J Z Bai A B Balantekin et al ldquoImprovedmeasurement of electron antineutrino disappearance at DayaBayrdquo Chinese Physics C vol 37 Article ID 011001 21 pages 2013
[73] J K Ahn S Chebotaryov J H Choi et al ldquoObservationof reactor electron antineutrinos disappearance in the RENOexperimentrdquo Physical Review Letters vol 108 Article ID 1918026 pages 2012
[74] Y Abe C Aberle J C dos Anjos et al ldquoReactor electronantineutrino disappearance in the Double Chooz experimentrdquoPhysical Review D vol 86 Article ID 052008 2012
[75] K Abe N Abgrall H Aihara et al ldquoEvidence of electronneutrino appearance in a muon neutrino beamrdquo PhysicalReview D vol 88 no 3 Article ID 032002 41 pages 2013
[76] A Schreckenberger Electron neutrino and antineutrino appear-ance in the MINOS detector [PhD thesis] University of Min-nesota Minneapolis Minn USA 2013
[77] D J Koskinen MINOS sterile neutrino search [PhD thesis]University College London London UK 2009
[78] M Apollonio A Baldini C Bemporad et al ldquoSearch forneutrino oscillations on a long base-line at the CHOOZ nuclearpower stationrdquoTheEuropean Physical Journal C vol 27 pp 331ndash374 2003
[79] G Tzanankos M Bishai M Diwan et alMINOS+ a proposalto FNAL to run MINOS with the medium energy NuMI beam[PhD thesis] University of Athens Athens Greece 2011
[80] A Aguilar L B Auerbach R L Burman et al ldquoEvidence forneutrino oscillations from the observation of ]
119890e appearance
in a ]120583beamrdquo Physical Review D vol 64 Article ID 112007 22
pages 2001[81] A A Aguilar-Arevalo C E Anderson S J Brice et al ldquoSearch
for electron antineutrino appearance at the Δ119898 sim 1 eV2 ScalerdquoPhysical Review Letters vol 103 no 11 Article ID 111801 2009
[82] A A Aguilar-Arevalo C E Anderson A O Bazarko et alldquoImproved search for V
120583rarr V119890oscillations in the MiniBooNE
experimentrdquo Physical Review Letter vol 110 no 10 Article ID161801 2013
[83] GMentionM Fechner T Lasserre et al ldquoReactor antineutrinoanomalyrdquo Physical Review D vol 83 Article ID 073006 20pages 2011
18 Advances in High Energy Physics
[84] KNAbazajianMAAcero S KAgarwalla et al ldquoLight sterileneutrinos a white paperrdquo httparxivorgabs12045379
[85] B Achkar R Aleksan M Avenier et al ldquoSearch for neutrinooscillations at 15 40 and 95meters from a nuclear power reactorat Bugeyrdquo Nuclear Physics B vol 434 no 3 pp 503ndash532 1995
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
High Energy PhysicsAdvances in
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
FluidsJournal of
Atomic and Molecular Physics
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in Condensed Matter Physics
OpticsInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
AstronomyAdvances in
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Superconductivity
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Statistical MechanicsInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
GravityJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
AstrophysicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Physics Research International
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Solid State PhysicsJournal of
Computational Methods in Physics
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Soft MatterJournal of
Hindawi Publishing Corporationhttpwwwhindawicom
AerodynamicsJournal of
Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
PhotonicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Biophysics
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
ThermodynamicsJournal of
14 Advances in High Energy Physics
1000
500
00 5 10 15 20
E (GeV)
MINOS+NOAMINOS
Preliminary
Simulated beam54 kton 6 times 1020 POT
120583CC
even
ts (G
eV)
Figure 20 The ]120583energy spectrum that will be observed by the
MINOS+ FD compared to the spectra observed by MINOS andNO]A
peaking at around 7GeV In this configuration MINOS+ willobserve around 4000 CC ]
120583interactions in the FD each
year unprecedented statistics for a long-baseline oscillationexperimentThis will offer a unique high precision test of thethree-flavour oscillation paradigm
MINOS+ will be able to make a very sensitive searchfor the sterile neutrinos suggested by the LSND [80] andMiniBooNE [81 82] data and by some interpretations ofreactor neutrino data [83] This search will cover more thanthree orders of magnitude in the mass splitting between thesterile and active neutrinos The signal that MINOS+ willsearch for is illustrated in Figure 21 Figure 21(a) illustratesthe increase in statistical precision thatMINOS+will provideon the ratio of the observed CC ]
120583interaction rate to
that expected without oscillations Figure 21(b) shows howthis ratio is modified if a sterile neutrino exists and mixeswith the active neutrinos an additional deficit of muonneutrino interactions occurs in the higher energy region ofthe spectrum In the model assumed here which introducesa single sterile neutrino state three new mixing angles areintroduced 120579
14 12057924 and 120579
34 An additional mass splitting
Δ1198982
43is also introduced The position in energy of the
additional deficit is governed by the value of the new masssplittingThemagnitude of the additional deficit in the CC ]
120583
interaction rate is governed primarily by the size of 12057924 this is
in comparison to short-baseline searches for ]119890disappearance
from reactors which are governed by 12057914and searches for ]
119890
appearance in ]120583beamswhich are governed by a combination
of 12057914
and 12057924 A detailed explanation of the global effort to
search for sterile neutrinos can be found in [84]The sensitivity of the MINOS+ experiment when com-
bined with the Bugey reactor neutrino data [85] is shown in
MINOS+ simulation
MINOS 1071 times 1021 POT06 times 1021 POT12 times 1021 POT18 times 1021 POT
120583su
rviv
al p
roba
bilit
y
Neutrino energy (GeV)0 5 10 15
15
1
05
0
(a)
P(
120583rarr
120583)
No sterile neutrinosΔm2
43 = 2 times 10minus2eV2 sin2(212057924) = 02
0 5 10 15 20
1
0
18
06
04
02
Neutrino energy (GeV)
(b)
Figure 21 (a) The black points show the ratio of the observed ]120583
energy spectrum to the expectation in the case of no oscillation inthe neutrino-dominated beam of MINOS The blue region showsthe statistical precision expected from MINOS+ (b) The black lineshows the muon neutrino survival probability in the case of nosterile neutrinos the red line shows how the probability would bemodified by the addition of mixing with a sterile neutrino
Figure 22 MINOS+ has the potential to rule out much of theLSND allowed region MINOS+ will begin taking data in thelate summer of 2013 and will continue taking data for at leasttwo years (Figure 22 assumes two years of data taking with aneutrino-dominated beam)
8 Conclusion
The MINOS experiment was conceived at a time when neu-trino oscillation had only recently been confirmed as thesolution to the problem of neutrino flavour change It has
Advances in High Energy Physics 15
Δm
2
10minus210minus2
10minus1
10minus1
10minus310minus4 1
1
10
102
LSND 90 CLLSND 99 CLKarmen2 90 CLBugey 90 CLlowast
MiniBooNE 90 CLMiniBooNE 99 CLMINOS+ and Bugeycombination 90 CL
sin22120579120583e
lowastGLoBES 2012 fit with new reactor fluxescourtesy of P Huber
Figure 22 The sensitivity of MINOS+ to the existence of sterileneutrinos when combined with data from the Bugey [85] reactorneutrino experiment Δ1198982 is the splitting between the three knownneutrino mass states and a new fourth state 120579
120583119890is the mixing angle
governing ]120583rarr ]119890transitions when a fourth sterile neutrino state
is introduced into the PMNSmixingmatrixThis figure assumes twoyears of MINOS+ running with a neutrino-dominated beam
played a hugely influential role in bringing neutrino oscilla-tion physics into an era of precision measurement MINOSrsquosmeasurement of the largest neutrino mass splitting is themost precise in the world MINOS has made the first directprecision measurement of the corresponding antineutrinoparameters a measurement that promises to remain theworldrsquos most precise for many years And MINOS has playeda role in the discovery of a nonzero value for 120579
13
Now that the value of 12057913is known the neutrino physics
community can move on to determine the neutrino masshierarchy and to search for CP violation in the neutrinosector MINOS has pioneered a number of techniques thatwill be used by future experiments The two-detector setupall important in reducing the impact of systematic uncer-tainties is the design of choice for any new experiment andMINOS has demonstrated methods of using a near detectorto determine the expectation at a far detector MINOS hasperformed the first search for ]
119890appearance in a ]
120583beam
and the first search for ]119890and ]119890appearance with significant
matter effects demonstrating the analysis techniques that willbe used to determine the mass hierarchy and CP violationparameter
In the second half of 2013 MINOS will begin taking dataas the MINOS+ experiment which will make ever more pre-cise tests of the three-flavour neutrino oscillation paradigmand set world-leading limits on the existence of sterileneutrinos This is an exciting future for an experiment thatwith a decade of data taking so far has already created alasting legacy for itself in our understanding of the neutrino
A comparison of themeasured neutrino and antineutrinomass splittings is shown in Figure 14 the difference betweenthe two is constrained to |Δ119898
2| minus |Δ119898
2| = (012
+024
minus026) times
10minus3 eV2
Acknowledgment
The work of the MINOS and MINOS+ collaborations issupported by the US DoE the UK STFC the US NSF theState and University of Minnesota the University of Athensin Greece and Brazilrsquos FAPESP and CNPq The authors aregrateful to the Minnesota Department of Natural Resourcesthe crew of the Soudan Underground Laboratory and thepersonnel of Fermilab for their vital contributions
References
[1] S Wojcicki ldquoLong baseline neutrino oscillation programe inthe United Statesrdquo Nuclear Physics B vol 77 no 1ndash3 pp 182ndash186 1999 Proceedings of the 18th International Conference onNeutrino Physics and Astrophysics (Neutrino rsquo98) TakayamaJapan June 1998
[2] R Davis Jr D S Harmer and K C Hoffman ldquoSearch forneutrinos from the sunrdquo Physical Review Letters vol 20 no 21pp 1205ndash1209 1968
[3] A I Abazov O L Anosov E L Faizov et al ldquoSearch forneutrinos from sun using the reactionGa-71 (electron-neutrinoe-) Ge-71rdquo Physical Review Letters vol 67 pp 3332ndash3335 1991
[4] P Anselmann W Hampel G Heusser et al ldquoSolar neutrinosobserved by GALLEX at gran sassordquo Physics Letters B vol 285no 4 pp 376ndash389 1992
[5] M Aglietta G Battistoni E Bellotti et al ldquoExperimentalstudy of atmospheric neutrino flux in the NUSEX experimentrdquoEurophysics Letters vol 8 no 7 article 611 1989
[6] K S Hirata ldquoObservation of a small atmospheric V120583V119890ratio in
Kamiokanderdquo Physics Letters B vol 280 no 1-2 pp 146ndash1521992
[7] R Becker-Szendy C B Bratton D Casper et al ldquoElectron-and muon-neutrino content of the atmospheric fluxrdquo PhysicalReview D vol 46 pp 3720ndash3724 1992
[8] K Daum W Rhode P Bareyre et al ldquoDetermination ofthe atmospheric neutrino spectra with the frejus detectorrdquoZeitschrift fur Physik C vol 66 no 3 pp 417ndash428 1995
[9] S Ahlen M Ambrosio R Antolini and G Auriemma ldquoAtmo-spheric neutrino flux measurement using upgoing muonsrdquoPhysics Letters B vol 357 no 3 pp 481ndash486 1995
[10] WMAllison G J Alner D S Ayres et al ldquoMeasurement of theatmospheric neutrino flavour composition in Soudan 2rdquoPhysicsLetters B vol 391 no 3-4 pp 491ndash500 1997
16 Advances in High Energy Physics
[11] Y Fukuda T Hayakawa E Ichihara et al ldquoEvidence foroscillation of atmospheric neutrinosrdquo Physical Review Lettersvol 81 no 8 pp 1562ndash1567 1998
[12] Q R Ahmad R C Allen T C Andersen et al ldquoMeasurementof charged current interactions produced by solar neutrinos atthe sudbury neutrino observatoryrdquo Physical Review Letters vol87 Article ID 071301 2001
[13] Q R Ahmad R C Allen T C Andersen et al ldquoDirect evidencefor neutrino flavor transformation from neutral-current inter-actions in the sudbury neutrino observatoryrdquo Physical ReviewLetters vol 89 Article ID 011301 6 pages 2002
[14] B Pontecorvo ldquoInverse beta processes and nonconservation oflepton chargerdquo Journal of Experimental and Theoretical Physicsvol 34 pp 172ndash173 1958
[15] V N Gribov and B Pontecorvo ldquoNeutrino astronomy andlepton chargerdquo Physics Letters B vol 28 pp 493ndash496 1969
[16] Z Maki M Nakagawa and S Sakata ldquoRemarks on the unifiedmodel of elementary particlesrdquo Progress of Theoretical Physicsvol 28 no 5 pp 870ndash880 1962
[17] P Adamson C Andreopoulos D J Auty et al ldquoFirst directobservation of muon antineutrino disappearancerdquo PhysicalReview Letters vol 107 no 2 Article ID 021801 2011
[18] P Adamson D J Auty D S Ayres et al ldquoSearch for thedisappearance of muon antineutrinos in the NuMI neutrinobeamrdquo Physical Review D vol 84 no 7 Article ID 071103 6pages 2011
[19] P Adamson D S Ayres C Backhouse et al ldquoImprovedmeasurement of muon antineutrino disappearance inMINOSrdquoPhysical Review Letters vol 108 no 19 Article ID 191801 5pages 2012
[20] P Adamson I Anghel C Backhouse et al ldquoMeasurementof Neutrino and Antineutrino Oscillations Using Beam andAtmospheric Data in MINOSrdquo Physical Review Letters vol 110no 25 Article ID 251801 6 pages 2013
[21] K Anderson B Bernstein D Boehnlein et al ldquoThe NuMIFacility Technical Design Reportrdquo FERMILAB-DESIGN-1998-01 1998
[22] D G Michael P Adamson T Alexopoulos et al ldquoObservationof muon neutrino disappearance with the MINOS detectors inthe NuMI neutrino beamrdquo Physical Review Letters vol 97 no19 Article ID 191801 6 pages 2006
[23] P Adamson C Andreopoulos K E Arms et al ldquoStudy ofmuon neutrino disappearance using the fermilab main injectorneutrino beamrdquo Physical Review D vol 77 no 7 Article ID072002 34 pages 2008
[24] P Adamson C Andreopoulos K E Arms et al ldquoMeasurementof neutrino oscillations with theMINOS detectors in the NuMIbeamrdquo Physical Review Letters vol 101 no 13 Article ID 1318025 pages 2008
[25] P Adamson C Andreopoulos R Armstrong et al ldquoMea-surement of the neutrino mass splitting and flavor mixing byMINOSrdquo Physical Review Letters vol 106 no 18 Article ID181801 6 pages 2011
[26] P Adamson C Andreopoulos K E Arms et al ldquoSearch formuon-neutrino to electron-neutrino transitions in MINOSrdquoPhysical Review Letters vol 103 no 26 Article ID 261802 5pages 2009
[27] PAdamsonCAndreopoulosD J Auty et al ldquoNew constraintsonmuon-neutrino to electron-neutrino transitions inMINOSrdquoPhysical ReviewD vol 82 no 5 Article ID 051102 6 pages 2010
[28] P Adamson D J Auty D S Ayres et al ldquoImproved search formuon-neutrino to electron-neutrino oscillations in MINOSrdquoPhysical Review Letters vol 107 no 18 Article ID 181802 6pages 2011
[29] P Adamson I Anghel C Backhouse et al ldquoElectron neutrinoand antineutrino appearance in the full MINOS data samplerdquoPhysical Review Letters vol 110 no 17 Article ID 171801 6 pages2013
[30] P Adamson C Andreopoulos K E Arms et al ldquoSearch foractive neutrino disappearance using neutral-current interac-tions in theMINOS long-baseline experimentrdquo Physical ReviewLetters vol 101 no 22 Article ID 221804 5 pages 2008
[31] P Adamson C Andreopoulos D J Auty et al ldquoSearch for ster-ile neutrino mixing in the MINOS long-baseline experimentrdquoPhysical Review D vol 81 no 5 Article ID 052004 18 pages2010
[32] P Adamson D J Auty D S Ayres et al ldquoActive to sterileneutrino mixing limits from neutral-current interactions inMINOSrdquo Physical Review Letters vol 107 no 1 Article ID011802 5 pages 2011
[33] Z Pavlovic Observation of disappearance of muon neutrinos inthe NuMI beam [PhD thesis] University of Texas at AustinAustin Tex USA 2008
[34] F Ballarini G Battistoni M Campanella et al ldquoThe FLUKAcode an overviewrdquo Journal of Physics vol 41 article 151 2006
[35] S Agostinelli J Allison K Amako et al ldquoGEANT4mdasha sim-ulation toolkitrdquo Nuclear Instruments and Methods in PhysicsResearch A vol 506 no 3 pp 250ndash303 2003
[36] G Battistoni F Cerutti A Fasso et al ldquoThe FLUKA codedescription and benchmarkingrdquo in Proceedings of the HadronicShower Simulation Workshop vol 896 of AIP Conference Pro-ceedings pp 31ndash49 Batavia Ill USA September 2006
[37] D G Michaele P Adamson T Alexopoulos et al ldquoThe mag-netized steel and scintillator calorimeters of the MINOS exper-imentrdquoNuclear Instruments and Methods in Physics Research Avol 596 no 2 pp 190ndash228 2008
[38] I E Stockdale A Bodek F Borcherding N Giokaris et alldquoLimits on muon-neutrino oscillations in the mass range 30 lt9987791198982lt 1000 eV2c4 rdquo Physical Review Letters vol 52 no 16 pp
1384ndash1388 1984[39] F Dydak G J Feldman C Guyot et al ldquoA search for V
120583
oscillations in the9987791198982 range 03ndash90 eV2 rdquo Physics Letters B vol134 no 3-4 pp 281ndash286 1984
[40] F Bergsma J Dorenbosch M Jonker et al ldquoA searchfor oscillations of muon neutrinos in an experiment withLEcong07 kmGeVrdquo Physics Letters B vol 142 no 1-2 pp 103ndash1101984
[41] M H Ahn E Aliu S Andringa et al ldquoMeasurement ofneutrino oscillation by the K2K experimentrdquo Physical ReviewD vol 74 no 7 Article ID 072003 39 pages 2006
[42] P Adamson T Alexopoulos W W M Allison et al ldquoFirstobservations of separated atmospheric V
120583and ]
120583events in the
MINOS detectorrdquo Physical Review D vol 73 no 7 Article ID072002 2006
[43] P Adamson C Andreopoulos K E Arms et al ldquoCharge-separated atmospheric neutrino-inducedmuons in theMINOSfar detectorrdquo Physical ReviewD vol 75 no 9 Article ID 09200314 pages 2007
[44] P Adamson C Backhouse G Barr et al ldquoMeasurements ofatmospheric neutrinos and antineutrinos in the MINOS fardetectorrdquo Physical Review D vol 86 no 5 Article ID 05200720 pages 2012
Advances in High Energy Physics 17
[45] M A Kordosky Hadronic interactions in the MINOS detectors[PhD thesis] University of Texas at Austin Austin Tex USA2004
[46] P L Vahle Electromagnetic interactions in the MINOS detectors[PhD thesis] University of Texas at Austin Austin Tex USA2004
[47] C Backhouse Measuring neutrino oscillation parameters using]120583disappearance inMINOS [PhD thesis] University of Oxford
Oxford UK 2011[48] T M Cover and P E Hart ldquoNearest neighbor pattern classifi-
cationrdquo IEEE Transactions on Information Theory vol 13 no 1pp 21ndash27 1967
[49] R Ospanov A measurement of muon neutrino disappearancewith the MINOS detectors and NuMI beam [PhD thesis]University of Texas at Austin Austin Tex USA 2008
[50] J S Marshall A study of muon neutrino disappearance with theMINOS detectors and the NuMI neutrino beam [PhD thesis]University of Cambridge Cambridge UK 2008
[51] J P OchoaA search formuon neutrino to electron neutrino oscil-lations in the MINOS Experiment [PhD thesis] The CaliforniaInstitute of Technology Pasadena Calif USA 2009
[52] R TonerMeasuring 12057913via muon neutrino to electron neutrino
oscillations in the MINOS experiment [PhD thesis] Universityof Cambridge Cambridge UK 2011
[53] A Holin Electron neutrino appearance in the MINOS experi-ment [PhD thesis] University College London London UK2010
[54] J Boehm Measurement of electron neutrino appearance withthe MINOS experiment [PhD thesis] Harvard UniversityCambridge Mass USA 2009
[55] G Tinti Sterile neutrino oscillations in MINOS and hadronproduction in pC collisions [PhD thesis] University of OxfordOxford UK 2010
[56] J J EvansMeasuring antineutrino oscillations with the MINOSexperiment [PhD thesis] University of Oxford Oxford UK2008
[57] S J ColemanAmeasurement of neutrino oscillations withmuonneutrinos in the MINOS experiment [PhD thesis] College ofWilliam ampMary Williamsburg Va USA 2011
[58] J S Mitchell Measuring ]120583disappearance with the MINOS
experiment [PhD thesis] University of Cambridge CambridgeUK 2011
[59] A McGowan Observation of deficit in NuMI neutrino-inducedrock and non-fiducial muons in MINOS far detector andmeasurement of neutrino oscillation parameters [PhD thesis]University of Minnesota Minneapolis Minn USA 2007
[60] M StraitMeasurement of neutrino oscillation parameters usinganti-fiducial charged current events in MINOS [PhD thesis]University of Minnesota Minneapolis Minn USA 2010
[61] Y Itow ldquoAtmospheric neutrinosmdashresults from running exper-imentsrdquo in Proceedings of the 25th International Conference onNeutrino Physics and Astrophysics (Neutrino rsquo12) Kyoto JapanJune 2012
[62] K Abe N Abgrall Y Ajima et al ldquoFirst muon-neutrinodisappearance study with an off-axis beamrdquo Physical Review Dvol 85 no 3 Article ID 031103 8 pages 2012
[63] K Nakamura ldquoReview of particle physicsrdquo Journal of Physics Gvol 37 Article ID 075021 2010
[64] L Wolfenstein ldquoNeutrino oscillations in matterrdquo PhysicalReview D vol 17 no 9 pp 2369ndash2374 1978
[65] J W F Valle ldquoResonant oscillations of massless neutrinos inmatterrdquo Physics Letters B vol 199 no 3 pp 432ndash436 1987
[66] M C Gonzalez-Garcia M M Guzzo P I Krastev et alldquoAtmospheric neutrino observations and flavor changing inter-actionsrdquo Physical Review Letters vol 82 no 16 pp 3202ndash32051999
[67] A Friedland C Lunardini and M Maltoni ldquoAtmosphericneutrinos as probes of neutrino-matter interactionsrdquo PhysicalReview D vol 70 no 11 Article ID 111301 2004
[68] Z IsvanAntineutrino oscillations and a Search for non-standardInteractions with the MINOS [PhD thesis] University of Pitts-burgh Pittsburgh Pa USA 2012
[69] W A Mann D Cherdack W Musial and T Kafka ldquoApparentmultiple 998779119898
32
2 in ]120583and V
120583survival oscillations from nonstan-
dard interactionmatter effectrdquo Physical Review D vol 82 no 11Article ID 113010 8 pages 2010
[70] J Kopp P A N Machado and S J Parke ldquoInterpretation ofMINOS data in terms of nonstandard neutrino interactionsrdquoPhysical Review D vol 82 no 11 Article ID 113002 12 pages2010
[71] J A B Coelho Investigacao de mecanismos alternativos aoscilacao de neutrinos no experimentos MINOS [PhD thesis]Universidade Estadual de Campinas Sao Paulo Brazil 2012
[72] F P An Q An J Z Bai A B Balantekin et al ldquoImprovedmeasurement of electron antineutrino disappearance at DayaBayrdquo Chinese Physics C vol 37 Article ID 011001 21 pages 2013
[73] J K Ahn S Chebotaryov J H Choi et al ldquoObservationof reactor electron antineutrinos disappearance in the RENOexperimentrdquo Physical Review Letters vol 108 Article ID 1918026 pages 2012
[74] Y Abe C Aberle J C dos Anjos et al ldquoReactor electronantineutrino disappearance in the Double Chooz experimentrdquoPhysical Review D vol 86 Article ID 052008 2012
[75] K Abe N Abgrall H Aihara et al ldquoEvidence of electronneutrino appearance in a muon neutrino beamrdquo PhysicalReview D vol 88 no 3 Article ID 032002 41 pages 2013
[76] A Schreckenberger Electron neutrino and antineutrino appear-ance in the MINOS detector [PhD thesis] University of Min-nesota Minneapolis Minn USA 2013
[77] D J Koskinen MINOS sterile neutrino search [PhD thesis]University College London London UK 2009
[78] M Apollonio A Baldini C Bemporad et al ldquoSearch forneutrino oscillations on a long base-line at the CHOOZ nuclearpower stationrdquoTheEuropean Physical Journal C vol 27 pp 331ndash374 2003
[79] G Tzanankos M Bishai M Diwan et alMINOS+ a proposalto FNAL to run MINOS with the medium energy NuMI beam[PhD thesis] University of Athens Athens Greece 2011
[80] A Aguilar L B Auerbach R L Burman et al ldquoEvidence forneutrino oscillations from the observation of ]
119890e appearance
in a ]120583beamrdquo Physical Review D vol 64 Article ID 112007 22
pages 2001[81] A A Aguilar-Arevalo C E Anderson S J Brice et al ldquoSearch
for electron antineutrino appearance at the Δ119898 sim 1 eV2 ScalerdquoPhysical Review Letters vol 103 no 11 Article ID 111801 2009
[82] A A Aguilar-Arevalo C E Anderson A O Bazarko et alldquoImproved search for V
120583rarr V119890oscillations in the MiniBooNE
experimentrdquo Physical Review Letter vol 110 no 10 Article ID161801 2013
[83] GMentionM Fechner T Lasserre et al ldquoReactor antineutrinoanomalyrdquo Physical Review D vol 83 Article ID 073006 20pages 2011
18 Advances in High Energy Physics
[84] KNAbazajianMAAcero S KAgarwalla et al ldquoLight sterileneutrinos a white paperrdquo httparxivorgabs12045379
[85] B Achkar R Aleksan M Avenier et al ldquoSearch for neutrinooscillations at 15 40 and 95meters from a nuclear power reactorat Bugeyrdquo Nuclear Physics B vol 434 no 3 pp 503ndash532 1995
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
High Energy PhysicsAdvances in
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
FluidsJournal of
Atomic and Molecular Physics
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in Condensed Matter Physics
OpticsInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
AstronomyAdvances in
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Superconductivity
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Statistical MechanicsInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
GravityJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
AstrophysicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Physics Research International
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Solid State PhysicsJournal of
Computational Methods in Physics
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Soft MatterJournal of
Hindawi Publishing Corporationhttpwwwhindawicom
AerodynamicsJournal of
Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
PhotonicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Biophysics
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
ThermodynamicsJournal of
Advances in High Energy Physics 15
Δm
2
10minus210minus2
10minus1
10minus1
10minus310minus4 1
1
10
102
LSND 90 CLLSND 99 CLKarmen2 90 CLBugey 90 CLlowast
MiniBooNE 90 CLMiniBooNE 99 CLMINOS+ and Bugeycombination 90 CL
sin22120579120583e
lowastGLoBES 2012 fit with new reactor fluxescourtesy of P Huber
Figure 22 The sensitivity of MINOS+ to the existence of sterileneutrinos when combined with data from the Bugey [85] reactorneutrino experiment Δ1198982 is the splitting between the three knownneutrino mass states and a new fourth state 120579
120583119890is the mixing angle
governing ]120583rarr ]119890transitions when a fourth sterile neutrino state
is introduced into the PMNSmixingmatrixThis figure assumes twoyears of MINOS+ running with a neutrino-dominated beam
played a hugely influential role in bringing neutrino oscilla-tion physics into an era of precision measurement MINOSrsquosmeasurement of the largest neutrino mass splitting is themost precise in the world MINOS has made the first directprecision measurement of the corresponding antineutrinoparameters a measurement that promises to remain theworldrsquos most precise for many years And MINOS has playeda role in the discovery of a nonzero value for 120579
13
Now that the value of 12057913is known the neutrino physics
community can move on to determine the neutrino masshierarchy and to search for CP violation in the neutrinosector MINOS has pioneered a number of techniques thatwill be used by future experiments The two-detector setupall important in reducing the impact of systematic uncer-tainties is the design of choice for any new experiment andMINOS has demonstrated methods of using a near detectorto determine the expectation at a far detector MINOS hasperformed the first search for ]
119890appearance in a ]
120583beam
and the first search for ]119890and ]119890appearance with significant
matter effects demonstrating the analysis techniques that willbe used to determine the mass hierarchy and CP violationparameter
In the second half of 2013 MINOS will begin taking dataas the MINOS+ experiment which will make ever more pre-cise tests of the three-flavour neutrino oscillation paradigmand set world-leading limits on the existence of sterileneutrinos This is an exciting future for an experiment thatwith a decade of data taking so far has already created alasting legacy for itself in our understanding of the neutrino
A comparison of themeasured neutrino and antineutrinomass splittings is shown in Figure 14 the difference betweenthe two is constrained to |Δ119898
2| minus |Δ119898
2| = (012
+024
minus026) times
10minus3 eV2
Acknowledgment
The work of the MINOS and MINOS+ collaborations issupported by the US DoE the UK STFC the US NSF theState and University of Minnesota the University of Athensin Greece and Brazilrsquos FAPESP and CNPq The authors aregrateful to the Minnesota Department of Natural Resourcesthe crew of the Soudan Underground Laboratory and thepersonnel of Fermilab for their vital contributions
References
[1] S Wojcicki ldquoLong baseline neutrino oscillation programe inthe United Statesrdquo Nuclear Physics B vol 77 no 1ndash3 pp 182ndash186 1999 Proceedings of the 18th International Conference onNeutrino Physics and Astrophysics (Neutrino rsquo98) TakayamaJapan June 1998
[2] R Davis Jr D S Harmer and K C Hoffman ldquoSearch forneutrinos from the sunrdquo Physical Review Letters vol 20 no 21pp 1205ndash1209 1968
[3] A I Abazov O L Anosov E L Faizov et al ldquoSearch forneutrinos from sun using the reactionGa-71 (electron-neutrinoe-) Ge-71rdquo Physical Review Letters vol 67 pp 3332ndash3335 1991
[4] P Anselmann W Hampel G Heusser et al ldquoSolar neutrinosobserved by GALLEX at gran sassordquo Physics Letters B vol 285no 4 pp 376ndash389 1992
[5] M Aglietta G Battistoni E Bellotti et al ldquoExperimentalstudy of atmospheric neutrino flux in the NUSEX experimentrdquoEurophysics Letters vol 8 no 7 article 611 1989
[6] K S Hirata ldquoObservation of a small atmospheric V120583V119890ratio in
Kamiokanderdquo Physics Letters B vol 280 no 1-2 pp 146ndash1521992
[7] R Becker-Szendy C B Bratton D Casper et al ldquoElectron-and muon-neutrino content of the atmospheric fluxrdquo PhysicalReview D vol 46 pp 3720ndash3724 1992
[8] K Daum W Rhode P Bareyre et al ldquoDetermination ofthe atmospheric neutrino spectra with the frejus detectorrdquoZeitschrift fur Physik C vol 66 no 3 pp 417ndash428 1995
[9] S Ahlen M Ambrosio R Antolini and G Auriemma ldquoAtmo-spheric neutrino flux measurement using upgoing muonsrdquoPhysics Letters B vol 357 no 3 pp 481ndash486 1995
[10] WMAllison G J Alner D S Ayres et al ldquoMeasurement of theatmospheric neutrino flavour composition in Soudan 2rdquoPhysicsLetters B vol 391 no 3-4 pp 491ndash500 1997
16 Advances in High Energy Physics
[11] Y Fukuda T Hayakawa E Ichihara et al ldquoEvidence foroscillation of atmospheric neutrinosrdquo Physical Review Lettersvol 81 no 8 pp 1562ndash1567 1998
[12] Q R Ahmad R C Allen T C Andersen et al ldquoMeasurementof charged current interactions produced by solar neutrinos atthe sudbury neutrino observatoryrdquo Physical Review Letters vol87 Article ID 071301 2001
[13] Q R Ahmad R C Allen T C Andersen et al ldquoDirect evidencefor neutrino flavor transformation from neutral-current inter-actions in the sudbury neutrino observatoryrdquo Physical ReviewLetters vol 89 Article ID 011301 6 pages 2002
[14] B Pontecorvo ldquoInverse beta processes and nonconservation oflepton chargerdquo Journal of Experimental and Theoretical Physicsvol 34 pp 172ndash173 1958
[15] V N Gribov and B Pontecorvo ldquoNeutrino astronomy andlepton chargerdquo Physics Letters B vol 28 pp 493ndash496 1969
[16] Z Maki M Nakagawa and S Sakata ldquoRemarks on the unifiedmodel of elementary particlesrdquo Progress of Theoretical Physicsvol 28 no 5 pp 870ndash880 1962
[17] P Adamson C Andreopoulos D J Auty et al ldquoFirst directobservation of muon antineutrino disappearancerdquo PhysicalReview Letters vol 107 no 2 Article ID 021801 2011
[18] P Adamson D J Auty D S Ayres et al ldquoSearch for thedisappearance of muon antineutrinos in the NuMI neutrinobeamrdquo Physical Review D vol 84 no 7 Article ID 071103 6pages 2011
[19] P Adamson D S Ayres C Backhouse et al ldquoImprovedmeasurement of muon antineutrino disappearance inMINOSrdquoPhysical Review Letters vol 108 no 19 Article ID 191801 5pages 2012
[20] P Adamson I Anghel C Backhouse et al ldquoMeasurementof Neutrino and Antineutrino Oscillations Using Beam andAtmospheric Data in MINOSrdquo Physical Review Letters vol 110no 25 Article ID 251801 6 pages 2013
[21] K Anderson B Bernstein D Boehnlein et al ldquoThe NuMIFacility Technical Design Reportrdquo FERMILAB-DESIGN-1998-01 1998
[22] D G Michael P Adamson T Alexopoulos et al ldquoObservationof muon neutrino disappearance with the MINOS detectors inthe NuMI neutrino beamrdquo Physical Review Letters vol 97 no19 Article ID 191801 6 pages 2006
[23] P Adamson C Andreopoulos K E Arms et al ldquoStudy ofmuon neutrino disappearance using the fermilab main injectorneutrino beamrdquo Physical Review D vol 77 no 7 Article ID072002 34 pages 2008
[24] P Adamson C Andreopoulos K E Arms et al ldquoMeasurementof neutrino oscillations with theMINOS detectors in the NuMIbeamrdquo Physical Review Letters vol 101 no 13 Article ID 1318025 pages 2008
[25] P Adamson C Andreopoulos R Armstrong et al ldquoMea-surement of the neutrino mass splitting and flavor mixing byMINOSrdquo Physical Review Letters vol 106 no 18 Article ID181801 6 pages 2011
[26] P Adamson C Andreopoulos K E Arms et al ldquoSearch formuon-neutrino to electron-neutrino transitions in MINOSrdquoPhysical Review Letters vol 103 no 26 Article ID 261802 5pages 2009
[27] PAdamsonCAndreopoulosD J Auty et al ldquoNew constraintsonmuon-neutrino to electron-neutrino transitions inMINOSrdquoPhysical ReviewD vol 82 no 5 Article ID 051102 6 pages 2010
[28] P Adamson D J Auty D S Ayres et al ldquoImproved search formuon-neutrino to electron-neutrino oscillations in MINOSrdquoPhysical Review Letters vol 107 no 18 Article ID 181802 6pages 2011
[29] P Adamson I Anghel C Backhouse et al ldquoElectron neutrinoand antineutrino appearance in the full MINOS data samplerdquoPhysical Review Letters vol 110 no 17 Article ID 171801 6 pages2013
[30] P Adamson C Andreopoulos K E Arms et al ldquoSearch foractive neutrino disappearance using neutral-current interac-tions in theMINOS long-baseline experimentrdquo Physical ReviewLetters vol 101 no 22 Article ID 221804 5 pages 2008
[31] P Adamson C Andreopoulos D J Auty et al ldquoSearch for ster-ile neutrino mixing in the MINOS long-baseline experimentrdquoPhysical Review D vol 81 no 5 Article ID 052004 18 pages2010
[32] P Adamson D J Auty D S Ayres et al ldquoActive to sterileneutrino mixing limits from neutral-current interactions inMINOSrdquo Physical Review Letters vol 107 no 1 Article ID011802 5 pages 2011
[33] Z Pavlovic Observation of disappearance of muon neutrinos inthe NuMI beam [PhD thesis] University of Texas at AustinAustin Tex USA 2008
[34] F Ballarini G Battistoni M Campanella et al ldquoThe FLUKAcode an overviewrdquo Journal of Physics vol 41 article 151 2006
[35] S Agostinelli J Allison K Amako et al ldquoGEANT4mdasha sim-ulation toolkitrdquo Nuclear Instruments and Methods in PhysicsResearch A vol 506 no 3 pp 250ndash303 2003
[36] G Battistoni F Cerutti A Fasso et al ldquoThe FLUKA codedescription and benchmarkingrdquo in Proceedings of the HadronicShower Simulation Workshop vol 896 of AIP Conference Pro-ceedings pp 31ndash49 Batavia Ill USA September 2006
[37] D G Michaele P Adamson T Alexopoulos et al ldquoThe mag-netized steel and scintillator calorimeters of the MINOS exper-imentrdquoNuclear Instruments and Methods in Physics Research Avol 596 no 2 pp 190ndash228 2008
[38] I E Stockdale A Bodek F Borcherding N Giokaris et alldquoLimits on muon-neutrino oscillations in the mass range 30 lt9987791198982lt 1000 eV2c4 rdquo Physical Review Letters vol 52 no 16 pp
1384ndash1388 1984[39] F Dydak G J Feldman C Guyot et al ldquoA search for V
120583
oscillations in the9987791198982 range 03ndash90 eV2 rdquo Physics Letters B vol134 no 3-4 pp 281ndash286 1984
[40] F Bergsma J Dorenbosch M Jonker et al ldquoA searchfor oscillations of muon neutrinos in an experiment withLEcong07 kmGeVrdquo Physics Letters B vol 142 no 1-2 pp 103ndash1101984
[41] M H Ahn E Aliu S Andringa et al ldquoMeasurement ofneutrino oscillation by the K2K experimentrdquo Physical ReviewD vol 74 no 7 Article ID 072003 39 pages 2006
[42] P Adamson T Alexopoulos W W M Allison et al ldquoFirstobservations of separated atmospheric V
120583and ]
120583events in the
MINOS detectorrdquo Physical Review D vol 73 no 7 Article ID072002 2006
[43] P Adamson C Andreopoulos K E Arms et al ldquoCharge-separated atmospheric neutrino-inducedmuons in theMINOSfar detectorrdquo Physical ReviewD vol 75 no 9 Article ID 09200314 pages 2007
[44] P Adamson C Backhouse G Barr et al ldquoMeasurements ofatmospheric neutrinos and antineutrinos in the MINOS fardetectorrdquo Physical Review D vol 86 no 5 Article ID 05200720 pages 2012
Advances in High Energy Physics 17
[45] M A Kordosky Hadronic interactions in the MINOS detectors[PhD thesis] University of Texas at Austin Austin Tex USA2004
[46] P L Vahle Electromagnetic interactions in the MINOS detectors[PhD thesis] University of Texas at Austin Austin Tex USA2004
[47] C Backhouse Measuring neutrino oscillation parameters using]120583disappearance inMINOS [PhD thesis] University of Oxford
Oxford UK 2011[48] T M Cover and P E Hart ldquoNearest neighbor pattern classifi-
cationrdquo IEEE Transactions on Information Theory vol 13 no 1pp 21ndash27 1967
[49] R Ospanov A measurement of muon neutrino disappearancewith the MINOS detectors and NuMI beam [PhD thesis]University of Texas at Austin Austin Tex USA 2008
[50] J S Marshall A study of muon neutrino disappearance with theMINOS detectors and the NuMI neutrino beam [PhD thesis]University of Cambridge Cambridge UK 2008
[51] J P OchoaA search formuon neutrino to electron neutrino oscil-lations in the MINOS Experiment [PhD thesis] The CaliforniaInstitute of Technology Pasadena Calif USA 2009
[52] R TonerMeasuring 12057913via muon neutrino to electron neutrino
oscillations in the MINOS experiment [PhD thesis] Universityof Cambridge Cambridge UK 2011
[53] A Holin Electron neutrino appearance in the MINOS experi-ment [PhD thesis] University College London London UK2010
[54] J Boehm Measurement of electron neutrino appearance withthe MINOS experiment [PhD thesis] Harvard UniversityCambridge Mass USA 2009
[55] G Tinti Sterile neutrino oscillations in MINOS and hadronproduction in pC collisions [PhD thesis] University of OxfordOxford UK 2010
[56] J J EvansMeasuring antineutrino oscillations with the MINOSexperiment [PhD thesis] University of Oxford Oxford UK2008
[57] S J ColemanAmeasurement of neutrino oscillations withmuonneutrinos in the MINOS experiment [PhD thesis] College ofWilliam ampMary Williamsburg Va USA 2011
[58] J S Mitchell Measuring ]120583disappearance with the MINOS
experiment [PhD thesis] University of Cambridge CambridgeUK 2011
[59] A McGowan Observation of deficit in NuMI neutrino-inducedrock and non-fiducial muons in MINOS far detector andmeasurement of neutrino oscillation parameters [PhD thesis]University of Minnesota Minneapolis Minn USA 2007
[60] M StraitMeasurement of neutrino oscillation parameters usinganti-fiducial charged current events in MINOS [PhD thesis]University of Minnesota Minneapolis Minn USA 2010
[61] Y Itow ldquoAtmospheric neutrinosmdashresults from running exper-imentsrdquo in Proceedings of the 25th International Conference onNeutrino Physics and Astrophysics (Neutrino rsquo12) Kyoto JapanJune 2012
[62] K Abe N Abgrall Y Ajima et al ldquoFirst muon-neutrinodisappearance study with an off-axis beamrdquo Physical Review Dvol 85 no 3 Article ID 031103 8 pages 2012
[63] K Nakamura ldquoReview of particle physicsrdquo Journal of Physics Gvol 37 Article ID 075021 2010
[64] L Wolfenstein ldquoNeutrino oscillations in matterrdquo PhysicalReview D vol 17 no 9 pp 2369ndash2374 1978
[65] J W F Valle ldquoResonant oscillations of massless neutrinos inmatterrdquo Physics Letters B vol 199 no 3 pp 432ndash436 1987
[66] M C Gonzalez-Garcia M M Guzzo P I Krastev et alldquoAtmospheric neutrino observations and flavor changing inter-actionsrdquo Physical Review Letters vol 82 no 16 pp 3202ndash32051999
[67] A Friedland C Lunardini and M Maltoni ldquoAtmosphericneutrinos as probes of neutrino-matter interactionsrdquo PhysicalReview D vol 70 no 11 Article ID 111301 2004
[68] Z IsvanAntineutrino oscillations and a Search for non-standardInteractions with the MINOS [PhD thesis] University of Pitts-burgh Pittsburgh Pa USA 2012
[69] W A Mann D Cherdack W Musial and T Kafka ldquoApparentmultiple 998779119898
32
2 in ]120583and V
120583survival oscillations from nonstan-
dard interactionmatter effectrdquo Physical Review D vol 82 no 11Article ID 113010 8 pages 2010
[70] J Kopp P A N Machado and S J Parke ldquoInterpretation ofMINOS data in terms of nonstandard neutrino interactionsrdquoPhysical Review D vol 82 no 11 Article ID 113002 12 pages2010
[71] J A B Coelho Investigacao de mecanismos alternativos aoscilacao de neutrinos no experimentos MINOS [PhD thesis]Universidade Estadual de Campinas Sao Paulo Brazil 2012
[72] F P An Q An J Z Bai A B Balantekin et al ldquoImprovedmeasurement of electron antineutrino disappearance at DayaBayrdquo Chinese Physics C vol 37 Article ID 011001 21 pages 2013
[73] J K Ahn S Chebotaryov J H Choi et al ldquoObservationof reactor electron antineutrinos disappearance in the RENOexperimentrdquo Physical Review Letters vol 108 Article ID 1918026 pages 2012
[74] Y Abe C Aberle J C dos Anjos et al ldquoReactor electronantineutrino disappearance in the Double Chooz experimentrdquoPhysical Review D vol 86 Article ID 052008 2012
[75] K Abe N Abgrall H Aihara et al ldquoEvidence of electronneutrino appearance in a muon neutrino beamrdquo PhysicalReview D vol 88 no 3 Article ID 032002 41 pages 2013
[76] A Schreckenberger Electron neutrino and antineutrino appear-ance in the MINOS detector [PhD thesis] University of Min-nesota Minneapolis Minn USA 2013
[77] D J Koskinen MINOS sterile neutrino search [PhD thesis]University College London London UK 2009
[78] M Apollonio A Baldini C Bemporad et al ldquoSearch forneutrino oscillations on a long base-line at the CHOOZ nuclearpower stationrdquoTheEuropean Physical Journal C vol 27 pp 331ndash374 2003
[79] G Tzanankos M Bishai M Diwan et alMINOS+ a proposalto FNAL to run MINOS with the medium energy NuMI beam[PhD thesis] University of Athens Athens Greece 2011
[80] A Aguilar L B Auerbach R L Burman et al ldquoEvidence forneutrino oscillations from the observation of ]
119890e appearance
in a ]120583beamrdquo Physical Review D vol 64 Article ID 112007 22
pages 2001[81] A A Aguilar-Arevalo C E Anderson S J Brice et al ldquoSearch
for electron antineutrino appearance at the Δ119898 sim 1 eV2 ScalerdquoPhysical Review Letters vol 103 no 11 Article ID 111801 2009
[82] A A Aguilar-Arevalo C E Anderson A O Bazarko et alldquoImproved search for V
120583rarr V119890oscillations in the MiniBooNE
experimentrdquo Physical Review Letter vol 110 no 10 Article ID161801 2013
[83] GMentionM Fechner T Lasserre et al ldquoReactor antineutrinoanomalyrdquo Physical Review D vol 83 Article ID 073006 20pages 2011
18 Advances in High Energy Physics
[84] KNAbazajianMAAcero S KAgarwalla et al ldquoLight sterileneutrinos a white paperrdquo httparxivorgabs12045379
[85] B Achkar R Aleksan M Avenier et al ldquoSearch for neutrinooscillations at 15 40 and 95meters from a nuclear power reactorat Bugeyrdquo Nuclear Physics B vol 434 no 3 pp 503ndash532 1995
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
High Energy PhysicsAdvances in
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
FluidsJournal of
Atomic and Molecular Physics
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in Condensed Matter Physics
OpticsInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
AstronomyAdvances in
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Superconductivity
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Statistical MechanicsInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
GravityJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
AstrophysicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Physics Research International
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Solid State PhysicsJournal of
Computational Methods in Physics
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Soft MatterJournal of
Hindawi Publishing Corporationhttpwwwhindawicom
AerodynamicsJournal of
Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
PhotonicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Biophysics
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
ThermodynamicsJournal of
16 Advances in High Energy Physics
[11] Y Fukuda T Hayakawa E Ichihara et al ldquoEvidence foroscillation of atmospheric neutrinosrdquo Physical Review Lettersvol 81 no 8 pp 1562ndash1567 1998
[12] Q R Ahmad R C Allen T C Andersen et al ldquoMeasurementof charged current interactions produced by solar neutrinos atthe sudbury neutrino observatoryrdquo Physical Review Letters vol87 Article ID 071301 2001
[13] Q R Ahmad R C Allen T C Andersen et al ldquoDirect evidencefor neutrino flavor transformation from neutral-current inter-actions in the sudbury neutrino observatoryrdquo Physical ReviewLetters vol 89 Article ID 011301 6 pages 2002
[14] B Pontecorvo ldquoInverse beta processes and nonconservation oflepton chargerdquo Journal of Experimental and Theoretical Physicsvol 34 pp 172ndash173 1958
[15] V N Gribov and B Pontecorvo ldquoNeutrino astronomy andlepton chargerdquo Physics Letters B vol 28 pp 493ndash496 1969
[16] Z Maki M Nakagawa and S Sakata ldquoRemarks on the unifiedmodel of elementary particlesrdquo Progress of Theoretical Physicsvol 28 no 5 pp 870ndash880 1962
[17] P Adamson C Andreopoulos D J Auty et al ldquoFirst directobservation of muon antineutrino disappearancerdquo PhysicalReview Letters vol 107 no 2 Article ID 021801 2011
[18] P Adamson D J Auty D S Ayres et al ldquoSearch for thedisappearance of muon antineutrinos in the NuMI neutrinobeamrdquo Physical Review D vol 84 no 7 Article ID 071103 6pages 2011
[19] P Adamson D S Ayres C Backhouse et al ldquoImprovedmeasurement of muon antineutrino disappearance inMINOSrdquoPhysical Review Letters vol 108 no 19 Article ID 191801 5pages 2012
[20] P Adamson I Anghel C Backhouse et al ldquoMeasurementof Neutrino and Antineutrino Oscillations Using Beam andAtmospheric Data in MINOSrdquo Physical Review Letters vol 110no 25 Article ID 251801 6 pages 2013
[21] K Anderson B Bernstein D Boehnlein et al ldquoThe NuMIFacility Technical Design Reportrdquo FERMILAB-DESIGN-1998-01 1998
[22] D G Michael P Adamson T Alexopoulos et al ldquoObservationof muon neutrino disappearance with the MINOS detectors inthe NuMI neutrino beamrdquo Physical Review Letters vol 97 no19 Article ID 191801 6 pages 2006
[23] P Adamson C Andreopoulos K E Arms et al ldquoStudy ofmuon neutrino disappearance using the fermilab main injectorneutrino beamrdquo Physical Review D vol 77 no 7 Article ID072002 34 pages 2008
[24] P Adamson C Andreopoulos K E Arms et al ldquoMeasurementof neutrino oscillations with theMINOS detectors in the NuMIbeamrdquo Physical Review Letters vol 101 no 13 Article ID 1318025 pages 2008
[25] P Adamson C Andreopoulos R Armstrong et al ldquoMea-surement of the neutrino mass splitting and flavor mixing byMINOSrdquo Physical Review Letters vol 106 no 18 Article ID181801 6 pages 2011
[26] P Adamson C Andreopoulos K E Arms et al ldquoSearch formuon-neutrino to electron-neutrino transitions in MINOSrdquoPhysical Review Letters vol 103 no 26 Article ID 261802 5pages 2009
[27] PAdamsonCAndreopoulosD J Auty et al ldquoNew constraintsonmuon-neutrino to electron-neutrino transitions inMINOSrdquoPhysical ReviewD vol 82 no 5 Article ID 051102 6 pages 2010
[28] P Adamson D J Auty D S Ayres et al ldquoImproved search formuon-neutrino to electron-neutrino oscillations in MINOSrdquoPhysical Review Letters vol 107 no 18 Article ID 181802 6pages 2011
[29] P Adamson I Anghel C Backhouse et al ldquoElectron neutrinoand antineutrino appearance in the full MINOS data samplerdquoPhysical Review Letters vol 110 no 17 Article ID 171801 6 pages2013
[30] P Adamson C Andreopoulos K E Arms et al ldquoSearch foractive neutrino disappearance using neutral-current interac-tions in theMINOS long-baseline experimentrdquo Physical ReviewLetters vol 101 no 22 Article ID 221804 5 pages 2008
[31] P Adamson C Andreopoulos D J Auty et al ldquoSearch for ster-ile neutrino mixing in the MINOS long-baseline experimentrdquoPhysical Review D vol 81 no 5 Article ID 052004 18 pages2010
[32] P Adamson D J Auty D S Ayres et al ldquoActive to sterileneutrino mixing limits from neutral-current interactions inMINOSrdquo Physical Review Letters vol 107 no 1 Article ID011802 5 pages 2011
[33] Z Pavlovic Observation of disappearance of muon neutrinos inthe NuMI beam [PhD thesis] University of Texas at AustinAustin Tex USA 2008
[34] F Ballarini G Battistoni M Campanella et al ldquoThe FLUKAcode an overviewrdquo Journal of Physics vol 41 article 151 2006
[35] S Agostinelli J Allison K Amako et al ldquoGEANT4mdasha sim-ulation toolkitrdquo Nuclear Instruments and Methods in PhysicsResearch A vol 506 no 3 pp 250ndash303 2003
[36] G Battistoni F Cerutti A Fasso et al ldquoThe FLUKA codedescription and benchmarkingrdquo in Proceedings of the HadronicShower Simulation Workshop vol 896 of AIP Conference Pro-ceedings pp 31ndash49 Batavia Ill USA September 2006
[37] D G Michaele P Adamson T Alexopoulos et al ldquoThe mag-netized steel and scintillator calorimeters of the MINOS exper-imentrdquoNuclear Instruments and Methods in Physics Research Avol 596 no 2 pp 190ndash228 2008
[38] I E Stockdale A Bodek F Borcherding N Giokaris et alldquoLimits on muon-neutrino oscillations in the mass range 30 lt9987791198982lt 1000 eV2c4 rdquo Physical Review Letters vol 52 no 16 pp
1384ndash1388 1984[39] F Dydak G J Feldman C Guyot et al ldquoA search for V
120583
oscillations in the9987791198982 range 03ndash90 eV2 rdquo Physics Letters B vol134 no 3-4 pp 281ndash286 1984
[40] F Bergsma J Dorenbosch M Jonker et al ldquoA searchfor oscillations of muon neutrinos in an experiment withLEcong07 kmGeVrdquo Physics Letters B vol 142 no 1-2 pp 103ndash1101984
[41] M H Ahn E Aliu S Andringa et al ldquoMeasurement ofneutrino oscillation by the K2K experimentrdquo Physical ReviewD vol 74 no 7 Article ID 072003 39 pages 2006
[42] P Adamson T Alexopoulos W W M Allison et al ldquoFirstobservations of separated atmospheric V
120583and ]
120583events in the
MINOS detectorrdquo Physical Review D vol 73 no 7 Article ID072002 2006
[43] P Adamson C Andreopoulos K E Arms et al ldquoCharge-separated atmospheric neutrino-inducedmuons in theMINOSfar detectorrdquo Physical ReviewD vol 75 no 9 Article ID 09200314 pages 2007
[44] P Adamson C Backhouse G Barr et al ldquoMeasurements ofatmospheric neutrinos and antineutrinos in the MINOS fardetectorrdquo Physical Review D vol 86 no 5 Article ID 05200720 pages 2012
Advances in High Energy Physics 17
[45] M A Kordosky Hadronic interactions in the MINOS detectors[PhD thesis] University of Texas at Austin Austin Tex USA2004
[46] P L Vahle Electromagnetic interactions in the MINOS detectors[PhD thesis] University of Texas at Austin Austin Tex USA2004
[47] C Backhouse Measuring neutrino oscillation parameters using]120583disappearance inMINOS [PhD thesis] University of Oxford
Oxford UK 2011[48] T M Cover and P E Hart ldquoNearest neighbor pattern classifi-
cationrdquo IEEE Transactions on Information Theory vol 13 no 1pp 21ndash27 1967
[49] R Ospanov A measurement of muon neutrino disappearancewith the MINOS detectors and NuMI beam [PhD thesis]University of Texas at Austin Austin Tex USA 2008
[50] J S Marshall A study of muon neutrino disappearance with theMINOS detectors and the NuMI neutrino beam [PhD thesis]University of Cambridge Cambridge UK 2008
[51] J P OchoaA search formuon neutrino to electron neutrino oscil-lations in the MINOS Experiment [PhD thesis] The CaliforniaInstitute of Technology Pasadena Calif USA 2009
[52] R TonerMeasuring 12057913via muon neutrino to electron neutrino
oscillations in the MINOS experiment [PhD thesis] Universityof Cambridge Cambridge UK 2011
[53] A Holin Electron neutrino appearance in the MINOS experi-ment [PhD thesis] University College London London UK2010
[54] J Boehm Measurement of electron neutrino appearance withthe MINOS experiment [PhD thesis] Harvard UniversityCambridge Mass USA 2009
[55] G Tinti Sterile neutrino oscillations in MINOS and hadronproduction in pC collisions [PhD thesis] University of OxfordOxford UK 2010
[56] J J EvansMeasuring antineutrino oscillations with the MINOSexperiment [PhD thesis] University of Oxford Oxford UK2008
[57] S J ColemanAmeasurement of neutrino oscillations withmuonneutrinos in the MINOS experiment [PhD thesis] College ofWilliam ampMary Williamsburg Va USA 2011
[58] J S Mitchell Measuring ]120583disappearance with the MINOS
experiment [PhD thesis] University of Cambridge CambridgeUK 2011
[59] A McGowan Observation of deficit in NuMI neutrino-inducedrock and non-fiducial muons in MINOS far detector andmeasurement of neutrino oscillation parameters [PhD thesis]University of Minnesota Minneapolis Minn USA 2007
[60] M StraitMeasurement of neutrino oscillation parameters usinganti-fiducial charged current events in MINOS [PhD thesis]University of Minnesota Minneapolis Minn USA 2010
[61] Y Itow ldquoAtmospheric neutrinosmdashresults from running exper-imentsrdquo in Proceedings of the 25th International Conference onNeutrino Physics and Astrophysics (Neutrino rsquo12) Kyoto JapanJune 2012
[62] K Abe N Abgrall Y Ajima et al ldquoFirst muon-neutrinodisappearance study with an off-axis beamrdquo Physical Review Dvol 85 no 3 Article ID 031103 8 pages 2012
[63] K Nakamura ldquoReview of particle physicsrdquo Journal of Physics Gvol 37 Article ID 075021 2010
[64] L Wolfenstein ldquoNeutrino oscillations in matterrdquo PhysicalReview D vol 17 no 9 pp 2369ndash2374 1978
[65] J W F Valle ldquoResonant oscillations of massless neutrinos inmatterrdquo Physics Letters B vol 199 no 3 pp 432ndash436 1987
[66] M C Gonzalez-Garcia M M Guzzo P I Krastev et alldquoAtmospheric neutrino observations and flavor changing inter-actionsrdquo Physical Review Letters vol 82 no 16 pp 3202ndash32051999
[67] A Friedland C Lunardini and M Maltoni ldquoAtmosphericneutrinos as probes of neutrino-matter interactionsrdquo PhysicalReview D vol 70 no 11 Article ID 111301 2004
[68] Z IsvanAntineutrino oscillations and a Search for non-standardInteractions with the MINOS [PhD thesis] University of Pitts-burgh Pittsburgh Pa USA 2012
[69] W A Mann D Cherdack W Musial and T Kafka ldquoApparentmultiple 998779119898
32
2 in ]120583and V
120583survival oscillations from nonstan-
dard interactionmatter effectrdquo Physical Review D vol 82 no 11Article ID 113010 8 pages 2010
[70] J Kopp P A N Machado and S J Parke ldquoInterpretation ofMINOS data in terms of nonstandard neutrino interactionsrdquoPhysical Review D vol 82 no 11 Article ID 113002 12 pages2010
[71] J A B Coelho Investigacao de mecanismos alternativos aoscilacao de neutrinos no experimentos MINOS [PhD thesis]Universidade Estadual de Campinas Sao Paulo Brazil 2012
[72] F P An Q An J Z Bai A B Balantekin et al ldquoImprovedmeasurement of electron antineutrino disappearance at DayaBayrdquo Chinese Physics C vol 37 Article ID 011001 21 pages 2013
[73] J K Ahn S Chebotaryov J H Choi et al ldquoObservationof reactor electron antineutrinos disappearance in the RENOexperimentrdquo Physical Review Letters vol 108 Article ID 1918026 pages 2012
[74] Y Abe C Aberle J C dos Anjos et al ldquoReactor electronantineutrino disappearance in the Double Chooz experimentrdquoPhysical Review D vol 86 Article ID 052008 2012
[75] K Abe N Abgrall H Aihara et al ldquoEvidence of electronneutrino appearance in a muon neutrino beamrdquo PhysicalReview D vol 88 no 3 Article ID 032002 41 pages 2013
[76] A Schreckenberger Electron neutrino and antineutrino appear-ance in the MINOS detector [PhD thesis] University of Min-nesota Minneapolis Minn USA 2013
[77] D J Koskinen MINOS sterile neutrino search [PhD thesis]University College London London UK 2009
[78] M Apollonio A Baldini C Bemporad et al ldquoSearch forneutrino oscillations on a long base-line at the CHOOZ nuclearpower stationrdquoTheEuropean Physical Journal C vol 27 pp 331ndash374 2003
[79] G Tzanankos M Bishai M Diwan et alMINOS+ a proposalto FNAL to run MINOS with the medium energy NuMI beam[PhD thesis] University of Athens Athens Greece 2011
[80] A Aguilar L B Auerbach R L Burman et al ldquoEvidence forneutrino oscillations from the observation of ]
119890e appearance
in a ]120583beamrdquo Physical Review D vol 64 Article ID 112007 22
pages 2001[81] A A Aguilar-Arevalo C E Anderson S J Brice et al ldquoSearch
for electron antineutrino appearance at the Δ119898 sim 1 eV2 ScalerdquoPhysical Review Letters vol 103 no 11 Article ID 111801 2009
[82] A A Aguilar-Arevalo C E Anderson A O Bazarko et alldquoImproved search for V
120583rarr V119890oscillations in the MiniBooNE
experimentrdquo Physical Review Letter vol 110 no 10 Article ID161801 2013
[83] GMentionM Fechner T Lasserre et al ldquoReactor antineutrinoanomalyrdquo Physical Review D vol 83 Article ID 073006 20pages 2011
18 Advances in High Energy Physics
[84] KNAbazajianMAAcero S KAgarwalla et al ldquoLight sterileneutrinos a white paperrdquo httparxivorgabs12045379
[85] B Achkar R Aleksan M Avenier et al ldquoSearch for neutrinooscillations at 15 40 and 95meters from a nuclear power reactorat Bugeyrdquo Nuclear Physics B vol 434 no 3 pp 503ndash532 1995
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
High Energy PhysicsAdvances in
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
FluidsJournal of
Atomic and Molecular Physics
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in Condensed Matter Physics
OpticsInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
AstronomyAdvances in
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Superconductivity
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Statistical MechanicsInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
GravityJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
AstrophysicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Physics Research International
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Solid State PhysicsJournal of
Computational Methods in Physics
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Soft MatterJournal of
Hindawi Publishing Corporationhttpwwwhindawicom
AerodynamicsJournal of
Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
PhotonicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Biophysics
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
ThermodynamicsJournal of
Advances in High Energy Physics 17
[45] M A Kordosky Hadronic interactions in the MINOS detectors[PhD thesis] University of Texas at Austin Austin Tex USA2004
[46] P L Vahle Electromagnetic interactions in the MINOS detectors[PhD thesis] University of Texas at Austin Austin Tex USA2004
[47] C Backhouse Measuring neutrino oscillation parameters using]120583disappearance inMINOS [PhD thesis] University of Oxford
Oxford UK 2011[48] T M Cover and P E Hart ldquoNearest neighbor pattern classifi-
cationrdquo IEEE Transactions on Information Theory vol 13 no 1pp 21ndash27 1967
[49] R Ospanov A measurement of muon neutrino disappearancewith the MINOS detectors and NuMI beam [PhD thesis]University of Texas at Austin Austin Tex USA 2008
[50] J S Marshall A study of muon neutrino disappearance with theMINOS detectors and the NuMI neutrino beam [PhD thesis]University of Cambridge Cambridge UK 2008
[51] J P OchoaA search formuon neutrino to electron neutrino oscil-lations in the MINOS Experiment [PhD thesis] The CaliforniaInstitute of Technology Pasadena Calif USA 2009
[52] R TonerMeasuring 12057913via muon neutrino to electron neutrino
oscillations in the MINOS experiment [PhD thesis] Universityof Cambridge Cambridge UK 2011
[53] A Holin Electron neutrino appearance in the MINOS experi-ment [PhD thesis] University College London London UK2010
[54] J Boehm Measurement of electron neutrino appearance withthe MINOS experiment [PhD thesis] Harvard UniversityCambridge Mass USA 2009
[55] G Tinti Sterile neutrino oscillations in MINOS and hadronproduction in pC collisions [PhD thesis] University of OxfordOxford UK 2010
[56] J J EvansMeasuring antineutrino oscillations with the MINOSexperiment [PhD thesis] University of Oxford Oxford UK2008
[57] S J ColemanAmeasurement of neutrino oscillations withmuonneutrinos in the MINOS experiment [PhD thesis] College ofWilliam ampMary Williamsburg Va USA 2011
[58] J S Mitchell Measuring ]120583disappearance with the MINOS
experiment [PhD thesis] University of Cambridge CambridgeUK 2011
[59] A McGowan Observation of deficit in NuMI neutrino-inducedrock and non-fiducial muons in MINOS far detector andmeasurement of neutrino oscillation parameters [PhD thesis]University of Minnesota Minneapolis Minn USA 2007
[60] M StraitMeasurement of neutrino oscillation parameters usinganti-fiducial charged current events in MINOS [PhD thesis]University of Minnesota Minneapolis Minn USA 2010
[61] Y Itow ldquoAtmospheric neutrinosmdashresults from running exper-imentsrdquo in Proceedings of the 25th International Conference onNeutrino Physics and Astrophysics (Neutrino rsquo12) Kyoto JapanJune 2012
[62] K Abe N Abgrall Y Ajima et al ldquoFirst muon-neutrinodisappearance study with an off-axis beamrdquo Physical Review Dvol 85 no 3 Article ID 031103 8 pages 2012
[63] K Nakamura ldquoReview of particle physicsrdquo Journal of Physics Gvol 37 Article ID 075021 2010
[64] L Wolfenstein ldquoNeutrino oscillations in matterrdquo PhysicalReview D vol 17 no 9 pp 2369ndash2374 1978
[65] J W F Valle ldquoResonant oscillations of massless neutrinos inmatterrdquo Physics Letters B vol 199 no 3 pp 432ndash436 1987
[66] M C Gonzalez-Garcia M M Guzzo P I Krastev et alldquoAtmospheric neutrino observations and flavor changing inter-actionsrdquo Physical Review Letters vol 82 no 16 pp 3202ndash32051999
[67] A Friedland C Lunardini and M Maltoni ldquoAtmosphericneutrinos as probes of neutrino-matter interactionsrdquo PhysicalReview D vol 70 no 11 Article ID 111301 2004
[68] Z IsvanAntineutrino oscillations and a Search for non-standardInteractions with the MINOS [PhD thesis] University of Pitts-burgh Pittsburgh Pa USA 2012
[69] W A Mann D Cherdack W Musial and T Kafka ldquoApparentmultiple 998779119898
32
2 in ]120583and V
120583survival oscillations from nonstan-
dard interactionmatter effectrdquo Physical Review D vol 82 no 11Article ID 113010 8 pages 2010
[70] J Kopp P A N Machado and S J Parke ldquoInterpretation ofMINOS data in terms of nonstandard neutrino interactionsrdquoPhysical Review D vol 82 no 11 Article ID 113002 12 pages2010
[71] J A B Coelho Investigacao de mecanismos alternativos aoscilacao de neutrinos no experimentos MINOS [PhD thesis]Universidade Estadual de Campinas Sao Paulo Brazil 2012
[72] F P An Q An J Z Bai A B Balantekin et al ldquoImprovedmeasurement of electron antineutrino disappearance at DayaBayrdquo Chinese Physics C vol 37 Article ID 011001 21 pages 2013
[73] J K Ahn S Chebotaryov J H Choi et al ldquoObservationof reactor electron antineutrinos disappearance in the RENOexperimentrdquo Physical Review Letters vol 108 Article ID 1918026 pages 2012
[74] Y Abe C Aberle J C dos Anjos et al ldquoReactor electronantineutrino disappearance in the Double Chooz experimentrdquoPhysical Review D vol 86 Article ID 052008 2012
[75] K Abe N Abgrall H Aihara et al ldquoEvidence of electronneutrino appearance in a muon neutrino beamrdquo PhysicalReview D vol 88 no 3 Article ID 032002 41 pages 2013
[76] A Schreckenberger Electron neutrino and antineutrino appear-ance in the MINOS detector [PhD thesis] University of Min-nesota Minneapolis Minn USA 2013
[77] D J Koskinen MINOS sterile neutrino search [PhD thesis]University College London London UK 2009
[78] M Apollonio A Baldini C Bemporad et al ldquoSearch forneutrino oscillations on a long base-line at the CHOOZ nuclearpower stationrdquoTheEuropean Physical Journal C vol 27 pp 331ndash374 2003
[79] G Tzanankos M Bishai M Diwan et alMINOS+ a proposalto FNAL to run MINOS with the medium energy NuMI beam[PhD thesis] University of Athens Athens Greece 2011
[80] A Aguilar L B Auerbach R L Burman et al ldquoEvidence forneutrino oscillations from the observation of ]
119890e appearance
in a ]120583beamrdquo Physical Review D vol 64 Article ID 112007 22
pages 2001[81] A A Aguilar-Arevalo C E Anderson S J Brice et al ldquoSearch
for electron antineutrino appearance at the Δ119898 sim 1 eV2 ScalerdquoPhysical Review Letters vol 103 no 11 Article ID 111801 2009
[82] A A Aguilar-Arevalo C E Anderson A O Bazarko et alldquoImproved search for V
120583rarr V119890oscillations in the MiniBooNE
experimentrdquo Physical Review Letter vol 110 no 10 Article ID161801 2013
[83] GMentionM Fechner T Lasserre et al ldquoReactor antineutrinoanomalyrdquo Physical Review D vol 83 Article ID 073006 20pages 2011
18 Advances in High Energy Physics
[84] KNAbazajianMAAcero S KAgarwalla et al ldquoLight sterileneutrinos a white paperrdquo httparxivorgabs12045379
[85] B Achkar R Aleksan M Avenier et al ldquoSearch for neutrinooscillations at 15 40 and 95meters from a nuclear power reactorat Bugeyrdquo Nuclear Physics B vol 434 no 3 pp 503ndash532 1995
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
High Energy PhysicsAdvances in
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
FluidsJournal of
Atomic and Molecular Physics
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in Condensed Matter Physics
OpticsInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
AstronomyAdvances in
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Superconductivity
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Statistical MechanicsInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
GravityJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
AstrophysicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Physics Research International
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Solid State PhysicsJournal of
Computational Methods in Physics
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Soft MatterJournal of
Hindawi Publishing Corporationhttpwwwhindawicom
AerodynamicsJournal of
Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
PhotonicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Biophysics
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
ThermodynamicsJournal of
18 Advances in High Energy Physics
[84] KNAbazajianMAAcero S KAgarwalla et al ldquoLight sterileneutrinos a white paperrdquo httparxivorgabs12045379
[85] B Achkar R Aleksan M Avenier et al ldquoSearch for neutrinooscillations at 15 40 and 95meters from a nuclear power reactorat Bugeyrdquo Nuclear Physics B vol 434 no 3 pp 503ndash532 1995
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
High Energy PhysicsAdvances in
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
FluidsJournal of
Atomic and Molecular Physics
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in Condensed Matter Physics
OpticsInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
AstronomyAdvances in
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Superconductivity
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Statistical MechanicsInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
GravityJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
AstrophysicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Physics Research International
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Solid State PhysicsJournal of
Computational Methods in Physics
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Soft MatterJournal of
Hindawi Publishing Corporationhttpwwwhindawicom
AerodynamicsJournal of
Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
PhotonicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Biophysics
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
ThermodynamicsJournal of
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
High Energy PhysicsAdvances in
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
FluidsJournal of
Atomic and Molecular Physics
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in Condensed Matter Physics
OpticsInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
AstronomyAdvances in
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Superconductivity
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Statistical MechanicsInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
GravityJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
AstrophysicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Physics Research International
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Solid State PhysicsJournal of
Computational Methods in Physics
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Soft MatterJournal of
Hindawi Publishing Corporationhttpwwwhindawicom
AerodynamicsJournal of
Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
PhotonicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Biophysics
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
ThermodynamicsJournal of