rencontres de moriond (6 th march 2005) c. mariani (infn rome) for k2k collaboration march 6 th,...

C.Mariani@XLth Rencontres de Moriond (6th March 2005)

C. Mariani (INFN Rome)for K2K collaboration

March 6th, 2005@XLth Rencontres de Moriond


K2K K2K CollaborationCollaboration

250km250km

JAPAN: High Energy Accelerator Research Organization (KEK) / Institute for Cosmic Ray Research (ICRR), Univ. of Tokyo / Kobe University / Kyoto University / Niigata University / Okayama University / Tokyo University of Science / Tohoku University

KOREA: Chonnam National University / Dongshin University / Korea University / Seoul National University

U.S.A.: Boston University / University of California, Irvine / University of Hawaii, Manoa / Massachusetts Institute of Technology / State University of New York at Stony Brook / University of Washington at Seattle

POLAND: Warsaw University / Solton Institute

Since 2002JAPAN: Hiroshima University / Osaka University U.S.A.: Duke UniversityCANADA: TRIUMF / University of British ColumbiaITALY: Rome FRANCE: Saclay SPAIN: Barcelona / Valencia SWITZERLAND: Geneva RUSSIA: INR-Moscow


1995 Proposed to study neutrino oscillation for atmospheric neutrinos

anomaly. 1999

Started taking data. 2000

Detected smaller number of neutrinos than the expectation at a distance of 250 km. Disfavored null oscillation at the 2 level.

2002 Observed indications of neutrino oscillation. The probability of

null oscillation is less than 1%. 2004

Confirm neutrino oscillation with both a deficit of Confirm neutrino oscillation with both a deficit of and the distortion of the Eand the distortion of the E spectrum. spectrum.

1. Introduction and history of K2K


2. K2K experiment

monitormonitor Near detectors

(ND)

+

Target+Horn200m

decay pipe

SK

100m ~250km

12GeV protons~1011/2.2sec(/10m10m)

~106/2.2sec(/40m40m)

~1 event/2days

Signal of oscillation at K2K Reduction of events Distortion of energy spectrum

(monitor the beam center)


Neutrino beam and the directional

control~1GeV neutrino beam by a dual horn system with 250kA.

<1mrad

The beam direction monitored by muons

Y centerX center

≤1 mrad

~5 years


Accumulated POT (Protons On Target)

prot

ons/

puls

e(×

1012

)Ac

cum

ulat

ed P

OT

(×10

18)

K2K-I K2K-II

10.5x1019 POT, 8.9×1019 POT for Analysis

Jan 03 Oct-Nov 04

K2K-I K2K-II


Neutrino spectrum and the far/near ratio

beam 250km

10-6

1.0 2.0

Far/Near Ratio

E(GeV)

beam MC w/PION Monitor

E (GeV)

energy spectrum

@ K2K near detector

622 10)250250()()(

Kmm

LLEfR

far

near


SK Events

(BG: 1.6 events within 500s 2.4×10-3 events in 1.5s)

TSKTspill

GPS

SKTOF=0.83msec

107 events

Decay electron cut.

20MeV Deposited Energy

No Activity in Outer DetectorEvent Vertex in Fiducial VolumeMore than 30MeV Deposited Energy

Analysis Time Window

500sec

5sec

TDIFF. (s)

-0.2TSK-Tspill-TOF1.3sec


3. Analysis Overview

Observation #, p and

interaction MC

Measurement(E), int.

KEK

Far/Near Ratio (beam MC with mon.)

Observation# and E

rec.Expectation# and E

rec.

(sin22, m2)

SK


NEUT: K2K Neutrino interaction MC

CC quasi elastic (CCQE) CC (resonant) single (CC-

1)

DIS

NC

/E (10-38cm2/GeV)

Total (NC+CC)

CC Total

CC quasi-elastic

DISCC single

NC single 0

E (GeV)


4. Near detector measurements

1KT Water Cherenkov Detector (1KT) Scintillating-fiber/Water sandwich Detector (SciFi) Lead Glass calorimeter (LG) before 2002 Scintillators Bar Detector (SciBar) after 2003 Muon Range Detector (MRD)

Muon range detector

LG calorimeter


4.1 1KT Flux measurement

The same detector technology as Super-K. Sensitive to low energy neutrinos.

KT

SK

KT

SK

KT

SKobsKTSK M

MdEEE

dEEENN

)()(

)()(exp

Far/Near Ratio (by MC)~1×10-6

M: Fiducial mass MSK=22,500Kton, MKT=25ton: efficiency SK-I(II)=77.0(78.2)%, KT=74.5%

expSKN =150.9 N =107+12

-10obsSK


4.2 SciBar neutrino interaction study Full Active Fine-Grained detector (target: CH).

Sensitive to a low momentum track. Identify CCQE events and other interactions (non-QE)

separately.

p

CCQE Candidate

CCQE non-QE

25 p (degree)

p =obs -CCQE

DATACC QECC 1CC coherent-CC multi-

2 track events

p


Neutrino energy reconstruction


A hint of K2K forward deficit.

SciBarnon-QE Events

K2K observed forward deficit. A source is non-QE events. For CC-1,

Suppression of ~q2/0.1[GeV2] at q2<0.1[GeV2] may exist.(0.1GeV2 value comes from fitting 2 track nonQE sample in SciBar)

For CC-coherent , The coherent may not exist.

We do not identify which process causes the effect. The MC CC-1 (coherent ) model is corrected phenomenologically.

Oscillation analysis is insensitive to the choice.

q2rec

(Data-MC)/MC

DATACC 1CC coherent-

Preliminary

q2rec (GeV/c)2

q2rec (GeV/c)2


4.3 Near Detector Spectrum Measurements

1KT Fully Contained 1 ring (FC1R) sample.

SciBar 1 track, 2 track QE (p≤25), 2 track nQE 2 track nQE

((pp>25>25)) where one track is SciFi

1 track, 2 track QE (p≤25), 2 track nQE (p>30) where one track is

After applying the low q2 suppression of nQE observed in SciBar, the angular distributions of all other samples are reasonably reproduced.


1KT: momentum and angular distributions.

with measured spectrum

(deg.)0 20 90

flux measurement

low q2 corr.

p (MeV/c)0 1600800

1Kt -like sampleQuasi elasticSingle pion


4.4 Near Detectors combined measurements

(p) for 1track, 2trackQE and 2track nQE samples (E), nQE/QE

Fitting parameters (E), nQE/QE ratio Detector uncertainties on the energy scale and the track

counting efficiency. The change of track counting efficiency by nuclear effect

uncertainties; proton re-scattering and interactions in a nucleus …

Strategy① Measure (E) in the more relevant region of 20 for 1KT

and 10 for SciFi and SciBar. ② Apply a low q2 correction factor to the CC-1 model (or

coherent ). ③ Measure nQE/QE ratio for the entire range.


0-0.5 GeV

0.5-0.75GeV

0.75-1.0GeV

1.0-1.5GeV

E QE (MC) nQE(MC)

MC templatesKT data

P (MeV/c)

(M

eV/c

)

• flux KEK(E) (8 bins)• interaction (nQE/QE)


Flux measurements

2=638.1 for 609 d.o.f

( E< 500) = 0.78 0.36 ( 500 E < 750) = 1.01 0.09 ( 750 E <1000) = 1.12 0.07 (1000 E <1500) = 1.00 (1500 E <2000) = 0.90 0.04 (2000 E <2500) = 1.07 0.06 (2500 E <3000) = 1.33 0.17 (3000 E ) = 1.04 0.18 nQE/QE = 1.02 0.10

The nQE/QE error of 10% is assigned based on the sensitivity of thefitted nonQE/QE value by varying the fit criteria.

>10(20 ) cut: nQE/QE=0.95 0.04 standard(CC-1 low q2 corr.):

nQE/QE=1.02 0.03 No coherent: =nQE/QE=1.06 0.03

(E) at KEK

E

preliminary


SciFi (K2K-IIa with measured spectrum)

P 1trk

P 2trkQE

P 2trknon-QE

1trk

2trkQE

2trknon-QE

0 2 (GeV/c) 0 40 (degree)

flux measurement

10


SciBar (with measured flux)

P 1trk

P 2trk QE

P 2trk nQE

1trk

2trk QE

2trk nQE

flux measurement

10


5. Super-K oscillation analysis

Total Number of events E

rec spectrum shape of FC-1ring- events Systematic error term

)(),2sin,(),2sin,(

),2sin,(22

2

xsyst

xshape

xnorm

x

fLfmLfmL

fmL

f x : Systematic error parameters

Normalization, Flux, and nQE/QE ratio are in fx

Near Detector measurements, Pion Monitor constraint, beam MC estimation, and Super-K systematic uncertainties.


K2K-SK events

K2K-all(K2K-I, K2K-II)

DATA(K2K-I, K2K-II)

MC(K2K-I, K2K-II)

FC 22.5kT 107(55, 52)

150.9(79.1*, 71.8)

1ring 67 (33, 34)

93.7(48.6, 45.1 )

-like 57(30, 27)

84.8(44.3, 40.5)

　　 e-like 10(3, 7)

8.8(4.3, 4.5)

Multi Ring 40(22, 18)

57.2(30.5, 26.7)

for Efor Erecrec

(56)

*Updated from the previous analysis


)( xnorm fL

150.9107

#SK Events

)( xshape fL

Expected shape(No Oscillation)

Erec[GeV]

KS probability=0.08%

cos)(

22)( 22

pEVmVVmmEVm

EN

NNrec

V: Nuclear potential

Toy MCToy MC

CC-QE assumption


Best fit values. sin221.51 m2 [eV2] = 2.1910-3

Best fit values in the physical region. sin221.00 m2 [eV2] = 2.7910-3

logL=0.75

6. Results

sin22=1.51 can occur due to a a statistical fluctuation with 12.6%.

A toy MC

sin22

m2

1.00

2.79

1.51

12.6%


NSKobs=107

NSKexp (best fit)=150.9

Erec[GeV]

Best FitKS prob.=36%

m2 [

eV2 ]

sin22

Data are consistent with the oscillation.

Based on lnL

preliminary


Log Likelihood difference from the minimum.

mm22<(1.87~3.58)×10<(1.87~3.58)×10-3-3 eV eV22 at sin at sin2222=1.0 (90% =1.0 (90% C.L.)C.L.)

lnL lnL

- 68%- 90%- 99%

- 68%- 90%- 99%

m2[eV2] sin22


disappearance versus E shape distortion

sin22sin22

m2 [

eV2 ]

m2 [

eV2 ]

NSK (#) E shape

Both disappearance of Both disappearance of and the distortion of and the distortion of EE spectrum have the consistent result. spectrum have the consistent result.


K2K-I vs K2K-II


Null oscillation probability

K2K-I K2K-II K2K-all disappearance 2.0% 3.7% 0.26%(3.0)E spectrum distortion 19.5% 5.4% 0.74% (2.6)Combined 1.3%*

(2.5)0.56%(2.8)

0.0050%(4.0)

K2K K2K confirmsconfirms neutrino oscillationneutrino oscillation discovered in Super-K atmospheric neutrinos.discovered in Super-K atmospheric neutrinos.

Disappearance of Disappearance of and distortion of the energy and distortion of the energy spectrum as expected in neutrino oscillation.spectrum as expected in neutrino oscillation.

The null oscillation probabilities are calculated based on lnL.

*: The value is changed from the previous one.


8. Summary With 8.91019 POT, K2K has confirmedhas confirmed neutrino

oscillations at 4.04.0(hep-ex/0411038)(hep-ex/0411038). Disappearance of 3.03.0 Distortion of E spectrum 2.62.6

- 68%- 90%- 99%

K2K new resultsK2K new resultspreliminary

0.006

0.0 0.2 0.4 0.6 0.8 1.0

0.002

0.004

m2[eV2]

sin22


Backup slide


Additional Error on nonQE

nonQE value depends on fitting condition. Small angle cut: 0.979 CC1 re-weighting: 1.056 No coherent : 1.093 CC1 re-weighting factor +/– 0.03 (1)

(SciBar only fit): +/– 4% In total, ~10% uncertainty exists.

Fitting error is ~5% add 10% to nonQE error.

Official value8%

3.5%


7. Other Physics in K2K (K2K-I data only)

CCall

NC

01

M(MeV)

+H2ONC10

sin22em

2 [eV

2 ]

90%CL limit

90%CL sensitivity

e search

PRL 93 (2004) 051801 =0.064 (our MC)=0.0650.0010.007

not NC10

1KT


NEUT: K2K Neutrino interaction MC

CC quasi elastic (CCQE) Smith and Moniz with

MA=1.1GeV CC (resonance) single (CC-1)

Rein and Sehgal’s with MA=1.1GeV

DIS GRV94 + JETSET with Bodek and

Yang correction. CC coherent

Rein&Sehgal with the cross section rescale by J. Marteau

NC+ Nuclear Effects

/E (10-38cm2/GeV)

Total (NC+CC)

CC Total

CC quasi-elastic

DISCC single

NC single 0

E (GeV)


Overall normalization error on Nsk for Nov99~

(Event)Stat 0.28 0.37%KT 3.32 4.37%SK 2.28 3.00%Flux +2.81

-2.59F/N +4.26

-5.55NC/CC +0.15

-0.23nQE/QE +0.38

-0.61CT 0.46 0.60%Total +6.53

-7.37

Central Value76.05evts

Take errors notconsidered in matrix

5.34%

KT: dominated by FV errorSK: also.

Errors


Null oscillation lnL

K2K-I K2K-II K2K-all disappearance 2.72 2.18 4.55E spectrum distortion 1.63 2.91 4.90Combined 4.33 5.19 9.90

K2K K2K confirmedconfirmed neutrino oscillationneutrino oscillation discovered in Super-K atmospheric neutrinos.discovered in Super-K atmospheric neutrinos.

Disappearance of Disappearance of and distortion of the energy and distortion of the energy spectrum as expected in neutrino oscillation.spectrum as expected in neutrino oscillation.

The null oscillation probabilities are calculated based on lnL.

preliminary

*: The value is changed from the previous one.


The change of NSKexp in K2K-I

(Bugs)

The detector position 295m 294m -1%

MC difference between KT and SK KT; MA(QE)=1.1 (NCel)KT=1.1×(NCel)SK SK; MA(QE)=1.0 Efficiency change! -1%

NSKexp Change ~2%

295m294m


CC-1 suppression versus coherent


Systematic Bias without the MC correction.

Oscillation Results

ND (SciBar) measurement

DATA; MC w/ CC-1 suppressionMC template; Default MC

systematic bias

flux nQE/QE

Toy MC

MC w/o low q2 correction sin22=1.00m2=2.65 ×10-3 eV2

Prob.(null oscillation)=0.0049%

Corrected MC for low q2

sin22=1.00m2=2.73×10-3eV2

Prob.(null oscillation)=0.011%

There is a small bias in nQE/QE There is a small bias in nQE/QE and the low energy flux.and the low energy flux.


Oscillation result with a default MC

Without low q2 MC correction

The result w/o low q2 MC correction gives the better (biased) measurement due to the more low energy flux and the smaller nQE/QE.


K2K-I vs K2K-II

Best fit values. sin221.08, 1.51 m2 [eV2] = 2.7310-3, 2.1910-3

Best fit values in the physical region. sin221.00, 1.00 m2 [eV2] = 2.8610-3 , 2.7910-3 logL=0.02, 0.75 KSK2K-I & K2K-II =77%


Erec for K2K-I and K2K-II

K2K-I K2K-II


K2K-I vs K2K-II


1KT sys error summary and the change. SciBar sys. error …


Systematic error Fiducial: updated +-4.0% (<- 4.0%) : Smy’s analysis Escale : updated +-0.3% FADC (scale) updated +-0.8% FADC(cut position) +-1.5% (New) : Shaomin’s

analysis Background +-0.5% Multi-event +-0.7% Event rate(New) +-2.0% Profile (New) +-0.3% KT origin +-4.9% (Prev. 4.4%) SK efficiency +-3.0% CT norm. +-0.3 % for K2K-II ±0.6% for K2K-I Far/Near +5.6 -7.3%

1KT sys. error


SciBar Systematic Error (2track/1track)

Detector oriented Vertex Matching Efficiency +2.7% -1.0% Threshold Effect (+-15%) +0.7% Xtalk Effect (2%/4%/6%) +1.1% -1.1% Finding Efficiency +0.9% -4.3% Total (Detector) +3.1% -4.5%

Nuclear Effect Proton Re-scattering +2.9% -2.6% Pion Absorption +1.7% -1.7% Pion inelastic scattering +2.3% -2.9% Total (Nuclear) +4.1% -4.2%

Total +5.1% -6.2%


Detector oriented Angle resolution +1.0% X-talk Effect +2.2% -2.9% Momentum scale (+-2.7%) +1.5% -4.3% Total (Detector) +2.8% -5.2%

Nuclear Effect Proton Re-scattering +2.9% -2.8% Pion Absorption -5.4% Pion inelastic scattering +0.3% -4.7% Total (Nuclear Effect) +2.9% -7.7%

Total +4.0% -9.3%

SciBar Systematic Error (2track

QE/2track nQE)


Track finding Efficiency 2nd Track Efficiency (MC)

MC true 2nd Track (NHITX/Y 3Hit)≧

Detected! (= 1. Could Find 2nd Track 2. Rec.track overlap with more than 1 true Hit)

Overall Eff. 59.0% >20Hit 85.3% >40Hit 91.1%

(This can be improved!)

Evaluated DATA/MC w/ Eye scan.

1.00.80.60.40.2

0 20 40 60 80 100 120 140 (NHIT)

Find

ing

Eff

icie

ncy


Eye scan Result

● Data (Eye)□ MC (Eye)

Integrated bin (>40Hits)

Eye scanners (M.Hasegawa ,K.Hiraide Y.Takubo,S.Yamamoto)

1.35 0.93 0.97 1.01 1.00 0.96 0.98 0.98


Entry <5 5 - 9 10 -14 15 -19 20 - 24 25 - 29 30 - 34 35 - 39 40 – (each bin MC) 0 265 2257 3824 3976 3654 3027 2406 8009 27418 DATA/ MC 0 1.35 0.93 0.97 1.01 1.00 0.96 0.98 0.98 0 0.54 0.10 0.06 0.05 0.04 0.03 0.03 0.02 　 (stat.err) Total 0 358 2108 3719 4034 3659 3017 2364 7849 27034 0 143 226 229 199 146 91 72 160 475

2track/1track : 0.5032 (27418/54106) 0.496 +/- 0.013 (27034/54490)

Systematic Error (Track finding Eff.) : + 0.9% , -4.3%

Systematic error (Finding Eff.)

2Track/1Track (default MC) vs 2Track/1Track (MC* )DATA

MC

Compared


Same as previous one except binning size is 125/2 nsec that is a half of intervals of two bunches.


Residual of K2K-SK event timing relative to neutrino beam bunches. Timing correlation is clearly seen and a sigma is obtained as about 30nsec.


Number of observed events (F.C. in fid. vol.) as a function of integrated CT


Number of observed events (F.C. in all inner volume) as a function of integrated CT


Results (without small angle) 1kt > 20deg., SciFi and SciBar > 10deg. In each E bin, fitted flux is consistent each other.

C.Mariani@XLth Rencontres de Moriond (6th March 2005)A

A=0.10 +/– 0.03

CC1q2/0.10

(Data–MC)/MCAgree quite well

By using SciBar 2track-nonQE and fitted flux, I looked for the best value of CC1 suppression.

Suppression factorq2/A (q2>A)

Scan A value and calculate 2 of distribution.

Calculate

2

SciBar 2track nonQE

CC1 suppression factor tuning


Results (CC1 re-weighted) CC1 re-weighting factor : q2/0.10 (q2<0.10) Flux is fixed nonQE value : 0.979( cut) 1.056(this result) (+8%)


Results (no coherent ) for comparison Coherent production removed.

Flux is fixed. nonQE value: 1.093(this results)

(CC1 re-weighting : 1.056 3.5% difference)


Results (no cut, no re-weighting)for comparison

Flux is consistent with cut results. nonQE is significantly small, and 2 is bad. nonQE : 0.856, 2 / dof = 773.8 / 595 = 1.30


Flux v.s. fitting condition

Official fluxFor comparison

For comparison

Fitted flux from cut, CC1 re-weighting and no coherent are consistent each other.


NonQE v.s. CC1 re-weighting factor (SciBar

only fit) CC1 re-weighting factor +/– 0.03 (1)

nonQE +/– 4%SciBar Only Fit


Likelihood for Oscillation analysis

2 2 2 2 2 2norm shape syst( ,sin 2 ; ) ( ,sin 2 ; ) ( ,sin 2 ; ) ( )x x xL m f L m f L m f L f

obsexpexp

obs

( ) exp( )!

N

normNL N

N

Poisson prob. for FC events

obs obs obs

exp e

obs

ep x px e xp

II

II

Ia Ib

Ia Ib

N N N

N

N

NN N

: # of observed events

: # of expected events

Period flux SK parametersK2K-Ia Ihorn = 200 kA

SK-IK2K-IbIhorn = 250 kAK2K-II SK-II

f x : Systematic error parameters


Likelihood for Normalization

KTobsexp

KT 250kA KT KT KTint

,SK 250kA SK-I 2 2 SKint

,

( )

( ) ( ,sin 2 , )

Ib

IbIb j

i ij ij Ibi j

R ji i ij ij j i Ib

i j

NN f

f f N M CT

f f f N P m E CT

KT 250

KTobsexp

KT

SK-II

kA KT KTint

,SK 250kA 2 2int

,

SK

( )

( ) ( ,sin 2 , )

IIj

i ij iji j

II

IIII

ij IIR j

i i ij j ii j

ff f N M

f f f N P

N

m

C

TE

NT

C

i: energy binj: Interaction mode

KTobsexp

KT 200kA KT KT KTint

,SK 200kA SK-I 2 2 SKint

,

( )

( ) ( ,sin 2 , )

Ia

IaIa j

ij ij Iai j

jij ij j i Ia

i j

NN f

f N M CT

f N P m E CT

Data/MC for# of events in KT

flux

Far/Near

# of interaction in MC

SK efficiency

1 ( )( )

jnQE

j QEf f j nQE

nQE/QE

2 2

2 2 2

( ,sin 2 , )

1 sin 2 sin (1.27 / ) ( )1 ( )

jP m E

m L E j CCj NC

1 ( )( )

( )CCnQE

NC

j CC QEf j CC nQE

j NCf


Likelihood for Spectrum Shape

1

1

2 2

2 2

( ; ,sin 2 ;

( ; ,sin 2 ; , , , ,

, , , , )

)

SK I

SK IIR

SK IISK II

RSK I

SK I

N

NER nQE

sha

ER nQEi

i

pe ii

L P

P E m

E m f f

f f

f f

f f

f

f

N: Normalization factor

?

??2 2

rec

2 2true

?rec true

( ; ,sin 2 , , ,

( ,

, , )1 d ( ; ,sin )2 )

S

SK I

KSK

SK

Ei R nQE

Rj true

E ij

j

SKf N f

P E m f f f f f

E f f E EP E mN

1 ( )( )nQE

j QEf j nQE

Nj (Erec,Etrue): Event fraction in MC

flux Far/Near nQE/QESKefficiency

SKEnergy Scale

1 ( )( )

( )CCnQE

NC

j CC QEf j CC nQE

j NCf


Likelihood for Systematic parameters

SK-I

, , 1 , ,, ,

1

1

Ia 2 Ib 2

2 2Ia Ib

E

1

I

2

I 2

2II

exp

exp

exp

( ) ( )exp2 2

( )

exp

( )2

exp2

SK II SSK I SK I

SK I

K II

SK II

t nQE NC nQE NCsyst nQE NC

t R RR

tt f M f

L f M f

f M f

M f

f f

f

f

f

SK-II

SK-IISK-I

2E

E 2

2E

( )2f

Overall Normalization

SK Energy Scale

neutrino flux, nQE/QE,NCFar/Near Ratio

SK efficiency

Systematic parameters for flux are common for SK-Ib and SK-II

# of free parameter in fit: 25 33 34 (fnQE fCC-nQE, fNC)


K2K-1 K2K-2

Reconstructed vertex distribution for r2 vs Z


Visible energy distribution for F.C. events in the fiducial volume in data (closed circle), M.C. expectation with no oscillation (solid histogram), oscillated with sin22=1.0,m2=2.0×10-3eV2 (dashed histogram), and oscillated with sin22=1.0,m2=3.0×10-3eV2 (dotted histogram).


Reconstructed muon momentum distribution for F.C. 1ring mu-like events in the fiducial volume in data (closed circle), M.C. expectation with no oscillation (solid histogram), oscillated with sin22=1.0,m2=2.0×10-3eV2 (dashed histogram), and oscillated with sin22=1.0,m2=3.0×10-3eV2 (dotted histogram).


The distribution of the reconstructed direction of muons relative to the direction from KEK to SK for F.C. 1ring mu-like events in the fiducial volume in data (closed circle), M.C. expectation with no oscillation (solid histogram), oscillated with sin22=1.0,m2=2.0×10-3eV2 (dashed histogram), and oscillated with sin22=1.0,m2=3.0×10-3eV2 (dotted histogram).


Reconstructed neutrino energy distribution for F.C. 1ring mu-like events in the fiducial volume in data (closed circle), M.C. expectation with no oscillation (solid histogram), oscillated with sin22=1.0,m2=2.0×10-3eV2 (dashed histogram), and oscillated with sin22=1.0,m2=3.0×10-3eV2 (dotted histogram).


Reconstructed neutrino energy distribution for F.C. 1ring mu-like events in the fiducial volume in data (closed circle), M.C. expectation with no oscillation (solid histogram), oscillated with sin22=1.0,m2=2.0×10-3eV2 (dashed histogram), and oscillated with sin22=1.0,m2=3.0×10-3eV2 (dotted histogram)


Reconstructed neutrino energy distribution for F.C. 1ring mu-like events in the fiducial volume in data (closed circle), M.C. expectation with no oscillation (solid histogram), oscillated with sin22=1.0,m2=2.0×10-3eV2 (dashed histogram), and oscillated with sin22=1.0,m2=3.0×10-3eV2 (dotted histogram).


Summary of SK-2 absolute energy calibration

• Data agree with MC within +/-1.9%

• Time variation : +/-0.9% total uncertainty : +/- 2.1%


Ring-counting likelihood for SK-2 -

like events

sub-GeV P<400MeV/c sub-GeV P>400MeV/c multi-GeV


PID distributions for SK-2

sub-GeV(Evis<1330MeV)

multi-GeV(Evis>1330MeV)


Systematic error on spectrumK2K-1

ring counting

PID

vertex

E scale

0.-0.51.9%

1.1%

2.0%

0.5-1.02.1%

0.5%

2.0%

1.-1.52.5%

0.7%

2.0%

1.5-2.05.9%

0.6%

2.0%

2.0-2.55.9%

0.7%

2.0%

2.5-5.9%

0.7%

2.0%

2.7%

K2K-2

ring counting

PID

vertex

E scale

0.-0.52.6%

2.5%

2.0%

0.5-1.02.2%

0.9%

2.0%

1.-1.57.9%

0.6%

2.0%

1.5-2.07.5%

0.5%

2.0%

2.0-2.57.1%

0.5%

2.0%

2.5-7.1%

0.5%

2.0%

2.1%

rencontres de moriond (6 th march 2005) c. mariani (infn rome) for k2k collaboration march 6 th,...

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