Recent Results from the ANTARES Neutrino Experiment

1. http://antares.in2p3.fr Recent Results from the ANTARES Neutrino Experiment P.Vernin CEA Saclay, IRFUOn behalf of the Antares collaboration

2. ANTARES shore station 40 km submarine cable 22 Institutes from7 European countries -2500m ANTARES Collaboration & detector site Bucarest

3. Understanding production mechanism (‘cosmic accelerators’) of HE cosmic rays • Study very energetic objects: • galactic: SN remnants, microquasars, ... • extragalactic: GRB, AGN,… • Search for Dark matter (wimps) • Exotic (magnetic monopoles, ...) Binary systems Micro-quasars The ANTARES Physics Goals SNR GRB AGN Neutralino Annihilation

4. Neutrino detection principle m (~ n) trajectory ANTARES detection principle 3D PMT array nm p, a p m Cherenkov light from m gč nm g 43° 2500 m depth Measurement : Time, position & amplitude of hits m interaction n

5. ~70 m The 12 string Antares Telescope • 25 storeys / line • 3 PMTs / storey • 900 PMTs 450 m 14.5 m 40 km to shore 100 m Junction Box Interlink cables Anchor/line socket

6. Basic detector element: storey Optical Beacon for timing calibration (blue LEDs) 1/4 floors 17” glass sphere 10” PMT Ham. R7081-20 14 stages Local Control Module (in the Ti-cylinder) Hydrophone RX

7. m n ANTARES Expected performance labs ~ 60 m (26 m) @ 470 nm (379 nm) leff (scattering)~ 300 m (100 m) @ 470 nm (370 nm)

8. 2001 – 2003: Main Electro-optical cable in 2001 Junction Box in 2002 Prototype Sector Line (PSL) & Mini Instrumentation Line (MIL) 2003 ANTARES Construction Milestones • 2005 – 2006: • Mini Instrumentation Line + OMs (MILOM)running since 12 April 2005 • Line 1 running since March 2006,first complete detector line 2006Line 1 • 2006-2007 • Lines 2 to 10 + instrumented lines deployed and connected. Start to take physics data • Mid-2008+: Physics with full detector !

9. Field view of  telescopes Mediterranean Sea, 43o North 2/3 of time: Galactic Centre AMANDA/IceCube South Pole 0.5  sr instantaneous common view 1.5  sr common view per day M. Circella – Status of ANTARES 9

10. Counting rate of a single PMT (median rate) 15 min. integration time

11. Acoustic positioning system 25 Position of hydrophone relative to line base location 20 14 8 20 day period March 2007 1 AutonomousTransponders Measured position resolution < 10 cm

12. Coincidence rates from 40K decays 10.5 ± 0.4 Hz 40K coincidence rate from Gaussian fit: 13.0 ± 0.5 Hz 13.0 ± 0.5 Hz Simulation: 12 Hz ± 4 Hz (sys)

13. LED Beacon measurements of OM timing resolution Time of signal in OMs relative to reference PMT 3 OMs Time difference between signals from 2 OMs in a storey (0.52 = 0.75 ns) • Electronics + calibration  < 0.5 ns - TTS in photomultipliers  ~ 1.3 ns - Light scattering + chromatic dispersion in sea water  ~ 2 ns  Limitation for angular resolution  0.2o – 0.3o 36 LEDs + reference PMT

14. Muon Signals This plot shows absorption of atmospheric muons in water and provides a major cross-check of the apparatus calibration

15. Atmospheric muon tracks • Run 21240 / Event 12505 • Zenith θ= 101o • P(c2,ndf) = 0.88 • Triggered hits • Hits used in fit • Single hits + Reconstruction with 1 line (poor sensitivity to azimut ): Altitude vs Time Hyperbola Algorithm minimizes χ2to find zenith angle of track Antarespreliminary μ Hit altitude (relative to mid detector) [m] Hit time [ns]

16. Atmospheric muon tracks • Triggered hits • Hits used in fit • Single hits + Antarespreliminary • 22753 / 3880 • q= 180o z [m] • P(c2,ndf) = 0.35 μ t [ns]

17. The first neutrino with 10 strings Preliminary

18. Zenith angle distribution Atmospheric muons (0.1 Hz) 5 lines, 120 days With quality cuts 78 neutrinos Atmospheric neutrinos Candidates (0.7/day)

19. 10 lines analysis (new) Data: Dec 2007 – Apr 2008; Ag runs : 100 active days Multi line Single line 88 neutrino 208 neutrino

20. Diffuse neutrino flux sensitivities Bartol2004+Naumov et al (PQPM) W&B limit/2 (transparentsources) W&B W&B

21. Conclusions and Outlook • ANTARES is the largest neutrino telescope in the Northern hemisphere • Detector is working well, within design specifications • Technical challenge successfully mastered • Data collection started • Neutrino candidates detected • 10 detection lines taking data since December 2007 • 12 detection line apparatus to be completed next week • The last two lines already deployed • Operation for science  5 years • R&D for acoustic HE neutrino detection • Multidisciplinary platform for associated sea sciences • Milestone towards a KM3 underwater detector.

22. SPARES

23. Examples of seismic events M. Circella – Status of ANTARES VLVnT08 23

24. Multidisciplinary research activities: sea current recording Data from the ADCP are currently being analyzed by NIOZ 24

25. 10 lines Sci.Linux 4 upgrade & Trigger modification Data quality Trigger rate: ~1 Hz (5 lines) ~2-3 Hz (10 lines) 19106 detected  with the 5 Lines Date (2007) Date (2007) 25

26. Majority Multi-directional efficiency 200 m 200 m 180 m 5 local coincidences or large pulses 350 m log10(E) 100 m Standard trigger… TRIGGER: •  5 L1 • causal connection between L1: • L0: PMT hit above 1/3 p.e. • L1: local coincidence (2 L0 in the OM triplet in t<20 ns) or a large pulse (> 3 p.e.) 26

27. Current status of the site Installed N IL07 L1 L5 L2 L3 L9 L4 L7 L6 L8 L11 • Deployed • Connection May 2008 Submarine cable to shore L10 L12 seismometer 100 m Junction box 27

28. Acoustic positioning system Muon signals Coincidences between signals on adjacent storeys Pedestal = background (including 40K, biolum.) Peak amplitude due to muon flux Peak offset, width and shape = function of muon angular distribution, spectrum, … Data/MC ratio ≈ 1.13

29. Line shape determination using tiltmeter-compasses & acoustic triangulations 5 position sampling points (hydrophones) & 25 gradients (tiltmeter& compass data from each storey) allow reconstruction of line shape Measured position resolution < 10 cm 29

30. upward Event display Characteristic pattern in function of zenith angle and point of closest approach between detection line and track Downward (background) 30

31. Atmospheric muons Rate of reconstructed atmospheric muons: • Agreement between simulations and data is within 10% 31

32. ANTARES effective area Ndet=Aeff × Time × Flux Effective area Effective area • The effective area relates the measured rate to the incoming flux: • Effective area for steady sources (visibility of the detector included). • Energy integration limits from 500 to 107 GeV. • Different spectral indexes for the source emission are considered. 32

33. ANTARES 1y Sensitivity to point sources with energy spectrum E-2 Sensitivity and upper limits for ANTARES compared with other experiments.  andE-2 fluxes from point-like sources versus declination 33

34. Expected sensitivity on diffuse flux of HE  • MACRO: Astropart.Phys.19:1-13,2003. • Baikal Astropart. Phys. 25, 140 (2006). • AMANDA-II (807 d) Phys.Rev.D76:042008,2007 • IceCube: Astrop. Phys. 20 (2004) 507 • WB= Waxman & Bahcall, PRD59 (1999) • MPR98, PRD 63 (2001) • SDSS91: Phys. Rev. Lett. 66(91)2697 MACRO BAIKAL ANTARES (1y) AMANDA II ANTARES (3y) ICECUBE 34