High Energy Neutrino Flux studied in the ANTARES Deep-Sea Telescope

1. High Energy Neutrino Flux studied in the ANTARES Deep-Sea Telescope • research goals: deep cosmos • the detector setup: deep sea • status and performance • point-source  flux • diffuse  flux • future aims • summary Herbert Löhner, KVI, University Groningen, The Netherlands on behalf of the ANTARES collaboration http://antares.in2p3.fr H. Löhner, High Energy Neutrino Flux

2. TeV  rays (p+X  0) in centre of our galaxy from supernova remnant RX J1713.7-39. Expect: p+X     n  p neutrino astronomy • intriguing science questions: • origin of cosmic rays  1020 eV ? • astrophysical acceleration mechanism? • origin of relativistic jets? • dark matter? HESS • cosmic sources of neutrinos • Active Galactic Nuclei: super-massive black hole • in center of galaxies • micro quasars: X-ray binaries (in our galaxy) • supernova remnants and shock acceleration neutrinos reach Earth undisturbed: need sensitivity and angular resolution H. Löhner, High Energy Neutrino Flux

3. nm m W - N ν X ν γc µ θc = 43º νμ p,  107 atm. per year  103 atm.  p   cosm.  detection principle neutrinos can interact through charged current interaction in the vicinity of a neutrino telescope up-going neutrinos passing through the Earth are free from atmospheric muon background  track reconstructed from  Cherenkov cone passing 3D grid of PMTs H. Löhner, High Energy Neutrino Flux

4. the telescope setup storey buoy 3 10” PMT/storey 25 storeys/line 12 detection lines: ~900 PMT + acoustic detection 350 m 14.5 m 45 km electro-optical cable to shore Junction box 100 m ~60-75 m readout cables at -2475 m completed May 2008 H. Löhner, High Energy Neutrino Flux

5. up-going muon: neutrino candidate reconstruction of muon trajectory from time, charge and position of PMT hits assuming relativistic muons emitting Cherenkov light: 34.8O up-going muon height (m)  time (ns)  H. Löhner, High Energy Neutrino Flux

6. m n expected performance: 12 lines angular resolution = difference between reconstructed and MC generated angles vs. neutrino energy mrec−mgener. mrec−ngener. dominated by kinematics • angular resolution • < 0.2° above  105 GeV • limited tracking accuracy due to time resolution: • Light scattering s ~ 1.0 ns • TTS in PMT s ~ 1.3 ns • time calibration s < 0.5 ns • OM position s < 10 cm (↔ s < 0.5 ns) dominated by reconstruction H. Löhner, High Energy Neutrino Flux

7. neutrino candidatesfrom track zenith distribution 5-line data (May-Dec. 2007)+ 9-12 line data (2008) 341 days detector live time, reconstruction BBfit v3r2, single- and multi-line fit: 1062 neutrino candidates: 3.1  candidates/day down-going up-going 1062  cand. elevation angle  good agreement with Monte Carlo: atmospheric neutrinos: 916 (30% syst. error) atmospheric muons: 40 (50% syst. error) H. Löhner, High Energy Neutrino Flux

8. neutrino yield per day for some periods: high level of bioluminescence decreases reconstruction efficiency H. Löhner, High Energy Neutrino Flux

9. performance: data rate Median rate of measured single photon counts: typ. 60 – 80 kHz caused by bioluminescence (~ 30 kHz) and 40K decay (~ 40 kHz) with occasional bursts of extreme high rates (~ MHz) caused by macro-organisms (depends on sea current): multidisciplinary research, oceanographic studies H. Löhner, High Energy Neutrino Flux

10. Badly reconstructed Well reconstructed search for point-like  sources data set: 2007-2008 data taken with 5, 9, 10, and 12 operating detector lines uncertainties in angle reconstruction: median: 0.50.1O 12-line data: 0.40.1O absolute orientation: 0.1O H. Löhner, High Energy Neutrino Flux

11. coordinates of 2190 neutrino candidates 24 source candidates Equatorial coordinates most signal-like cluster: occurs in p = 88% of background-only experiments no significant clusters of neutrino candidates H. Löhner, High Energy Neutrino Flux

12. best limits for the Southern sky H. Löhner, High Energy Neutrino Flux

13. search for diffuse  sources • background from • atmospheric : ~ E-3.5 • cosmic • neutrino models: ~ E-2 • search for high-energy diffuse-flux tail energy estimate R based on extra light from • delayed OM hits due to • high-energy EM showers (Physics Letters B 696 (2011) 16 no excess of high-energy events above expected flux from atmospheric  H. Löhner, High Energy Neutrino Flux

14. limits on diffuse neutrino flux competitive new diffuse-flux limit, some models predicting cosmic neutrino flux can be excluded H. Löhner, High Energy Neutrino Flux

15. Multi-Messenger astronomy Strategy: higher discovery potential by observing different probes higher significance by coincidence detection higher efficiency by relaxed cuts MoUs for joint research Alerts TAROT optical follow up: 10 s repositioning Ligo/Virgo Gravitational waves: trigger + dedicated analysis chain GCN GRB Coord. Network: γ satellites H. Löhner, High Energy Neutrino Flux

16. future plans: KM3NeT concept array of multi-PMT optical modules (OM) sensing Cherenkov light instrumented volume several km3 sensitive to all  flavours E > 0.1 GeV angular resolution min 0.1o for E > 10 TeV acceptance: up-going tracks, up to 10o above horizon   H. Löhner, High Energy Neutrino Flux

17. Summary • ANTARES completed since May 2008 • angular resolution < 0.2 degree for energies > 100 TeV • neutrino candidate events selected (3 - 5 events / day) • point sources: best limit for the Southern sky • competitive new diffuse-flux limit • multi-messenger observations on alert • KM3NeT development for several km3 observatory H. Löhner, High Energy Neutrino Flux