The High Energy Neutrino Sky as seen by Antares
Dorothea SamtlebenLeiden University / NIKHEF, Amsterdam
New windows to the Universe via high energy neutrinos
Particle Physics Atmosphere acts as ‘beam dump‘ for cosmic rays => Studies for - Prompt production (high energies) - Neutrino oscillations (low energies)
Dark Matter WIMPs accumulate in massive objects (Sun, Earth) => possibly annihilation signals observable,
Astrophysics
Neutrinos are valuable cosmic messengers coming undeflected from cosmic sources
Multimessenger approach exploited together withdetectors for electromagnetic radiation and gravitational waves
Neutrino sources Microquasars
Highly energetic particle acceleration needed to explainobserved cosmic ray energy spectrum
- g from inverse Compton scattering - g from synchrotron radiation of electrons - g from pion decay
Neutrino fluxes can be derived from g emission by assuming pion decay as origin of g
Xpp 0/ g
Xpp g/
gg
ee
SN1006Optical, radio, X-rays
Artist‘s view Artist‘s viewSupernova remnants
Gamma Ray Bursts
- Atmospheric neutrino flux ~ E-3
- Neutrino flux from cosmic sources ~ E-2
Mediterranean Field of View
> 75%> 25%
2 downward sensitivity assumed
5
CPPM, Marseille DSM/IRFU/CEA, Saclay APC, Paris LPC, Clermont-Ferrand IPHC, Strasbourg Univ. de H.-A., Mulhouse LAM, Marseille COM, Marseille GeoAzur Villefranche INSU-Division Technique
Univ./INFN of Bari Univ./INFN of Bologna Univ./INFN of Catania LNS-Catania Univ. Napoli Univ./INFN of Pisa Univ./INFN of Rome Univ./INFN of Genova
IFIC, Valencia UPV, Valencia UPC, Barcelona
NIKHEF, Amsterdam Leiden Utrecht KVI Groningen NIOZ Texel
ITEP,Moscow Moscow State Univ
University of Erlangen• Bamberg Observatory• Univ. of Wurzeburg
ISS, Bucarest
8 countries34 institutes~150 scientists+engineers LPRM, Oujda
The ANTARES Collaboration
42°
interaction
Sea floor
Cherenkov light from
3D PMTarray
p
p, a
Cosmic rays interact with atmosphere => showers, muons, neutrinos
Neutrinos arrive from cosmic sources
Muon neutrino interaction in Earth => Muon passes detector
Also showers reconstructable => sensitive also to e,t
ANTARES detector
40 km toshore
• 12 lines mounted on the sea floor (2475m deep)• 25 storeys / line• 3 Photomultipliers / storey
PMTPMT
Track reconstruction
Quality of track fit can be used to decrease misreconstruction => Use likelihood value and angular error estimate
~105 atmospheric muons per day~5 atmospheric neutrinos per day
Maximum likelihood fit using hit positions and times(nanosecond resolution)
Track reconstruction
Track resolution degrees In point source analysis
Point source analysis
Analysis 2007-2010 data (813 days), 4 108 events, 3058 neutrino candidates
Skymap of p-values in equatorial coordinates
Most significant cluster, p-value=0.026 (α, δ) = (−46.5◦, −65.0◦) 5(9) events are within 1(3) degrees s (2.2s)
Ap J 760:53 (2012)
Flux limit• Study for 51 potential neutrino sources:
• No significant excess => upper limits
• Best limits for d<-30
Diffuse neutrino fluxData 2007-2009, corresponding to 335 active daysDistinction of diffuse flux from atmospheric neutrinos by energy (harder spectrum expected from sources)
Energy estimator R based on hit multiplicityon Photomultipliers
Simulation of energy estimator RDistribution of R in data in comparison to MC expectations
E-2 flux at limit
Prompt neutrinos (RPQM)
Diffuse neutrino flux
E2F(E)90%= 5.3 10-8 GeV cm-2 s-1 sr-1
20 TeV<E<2.5 PeV90% upper limit assuming E-2 flux spectrum
Physics Letters B 696 (2011) 16
Atmospheric neutrino spectrum
PRELIMINARY
E2F(E)90%= 3.2 10-8 GeV cm-2 s-1 sr-1
45 TeV<E<6.3 PeV90% upper limit assuming E-2 flux spectrum
2008-2011 data used
Two different energy estimators: - dE/dx as evaluated from charge collected in the detector - Combined likelihood for hit/no-hit for all OMs
L: lengthe: efficiency
Atmospheric energy spectrum by unfolding measuredspectrum
New diffuse limit using dE/dx estimator
Neutrinos from Fermi Bubble
15
Fermi Bubbles:• Excess of ɣ-rays seen in Fermi data in extended distinct regions (each ~ 25000 light-years)• Homogenous intensity • Sharp edges• Flat E-2 spectrum (between 1 and 100 GeV)
• Background estimated from average of 3 equivalent regions
• Event selection optimized for best model rejection factor
Galactic coordinates
Good visibility for ANTARES
Upper limits
16
Data 2008-2011 Fermi Bubbles zone: Nobs = 16
Excluding Bubbles zone: <Nbg> = 11 = (9+12+12)/3 No significant excess → set upper limits
50 TeV cutoff100 TeV cutoff500 TeV cutoff No cutoff
Solid: 90% CL limitsDotted: model prediction
ANTARES preliminary
Upper limits with respect to different models
PRELIMINARY
Dotted: different models
Search for Dark Matter
• Dark Matter WIMPs accumulate in heavy objects (Sun, Galactic Center, Earth)
• Capture/Annihilation in equilibrium at the Sun core
• Annihilation e.g. in bb/tt/WW -> +..
• Model-independent event simulation using WIMPSIM
• Interactions in the Sun and flavor oscillation, regeneration of t in the Sun taken into account
c
rc <sv>
Search for Dark Matter
c
rc <sv>
Neutrino candidates in the direction towards the sun (angular distance y)
kinematics
c2 based track reconstruction efficient for low energies
Different detector configurations
Angular resolution (median)
Spin-independent cross-section limit for ANTARES 2007-2008 in CMSSM
Dark Matter limits from the sun
For CMSSM:Branching ratios = 1(for WW, bb, ττ)(Large variation ofbranching ratios overparameter space)
PRELIMINARY
Dark Matter limits from the sunSpin-dependent cross-section limit for ANTARES 2007-2008 in CMSSM
For CMSSM:Branching ratios = 1(for WW, bb, ττ)(Large variation ofbranching ratios overparameter space)
PRELIMINARY
Neutrino oscillation
)cos16200(sin1
)27.1(sin1)(
2322
2322
Em
ELmP
• Low energy atmospheric neutrinos important
• Baseline L from zenith angle
• Energy estimate from track length
• Different track reconstruction using multi-line and single-line events (only zenith reconstructed)
Single LineMulti Line
Dashed: with oscillation
Simulation of reconstructed neutrinos
DataBest FitNo oscillations
Antares, K2K, Minos, SuperK
For maximal mixing
m2=(3.1±0.9) 10-3 eV2
PhysLettB 714, 224 (2012)
KM3NeT
First Funding already available to allowstart of construction
2013-15 Building/Deployment of first batch of detectors2015++ Completion of Detector
Deep Sea Research Infrastructure in the Mediterranean Sea hosting a multi cubic kilometer neutrino telescope
Locations of the three pilot projects:ANTARES: ToulonNEMO: Capo PasseroNESTOR: Pylos
860m
Track resolution 0.1deg @ TeV
New detector concept:Sphere with 31 PMTs - good directionality - single photon counting
Configuration
Multiple building blocks640 strings (in total)20 storeys/string=> 12800 DOMs
1 building block
860m
Track resolution 0.1deg @ TeV
New detector concept:Sphere with 31 PMTs - good directionality - single photon counting
Configuration
Multiple building blocks640 strings (in total)20 storeys/string=> 12800 DOMs
First light of sphere with 31 PMTs in Antares
Rate histogram for multiplicity of coincidences -> seeing first muons!
Neutrino telescope in seawater successfully established with high angular resolution
Variety of physics analyses underway, first results published
Large several cubic kilometer array Km3NeT planned in the Mediterranean Sea
Construction of first KM3NeT detection units underwayFirst light with new optical module in Antares!
=> NEW WINDOW TO THE UNIVERSE BECOMES AVAILABLE