1. SUSY06, June 14th, 20061 The IceCube Neutrino Telescope and its capability to search for EHE neutrinos Shigeru Yoshida The Chiba University (for the IceCube collaboration)

2. SUSY06, June 14th, 20062 The IceCube Detector IceTop ~1 km 60 DOMs 2450m 1450m IceTop AMANDA Digital Optical Module 400ns/6.4  s time range 400 photoelectron/15ns measure individual photon arrival time 1~2ns time resolution

3. SUSY06, June 14th, 20063 The IceCube collaboration Antarctica

4. SUSY06, June 14th, 20064 This year’s strings deep in ice AMANDA 9 strings and 16 ice-top stations have been deployed Toward 70 strings - km 3 detector and more ~125m

5. SUSY06, June 14th, 20065 Where Are EHE Neutrinos From? GZK neutrino  e  e Beyond the Standard Model The standard scenario The standard scenario EHE cosmic-ray induced neutrinos The main energy range: E ~ 10 9-10 GeV  Exotic scenarios Top-Down neutrinos decays/interaction of massive particles (topological defects, SUSY, micro black hole, …) The main energy range: E ~ 10 11-15 GeV  EHE-CR X

6. SUSY06, June 14th, 20066 EHE Events in the Earth General neutrino event ID  through the Earth up-going events Earth is opaque for EHE neutrino EHE neutrino induced events are coming from above as down-going North down-going up-going  < 1PeV > PeV    EHE CR        EHE neutrino mean free path ~ 100 km << R Earth  cc  ~ 10 -6~-4 mb

7. SUSY06, June 14th, 20067 EHE Spectrum in Ice E GZK >> E Atm  GZK neutrino induced lepton and atmospheric muon fluxes at the IceCube depth S. Yoshida et. al. (2004) Phys. Rev. D 69 103004

8. SUSY06, June 14th, 20068 EHE Track in Detection Volume  and  tracks lose there energy by ‘radiative processes’ e+e-    pair-creation bremsstrahlung photo-nuclear e+e-

9. SUSY06, June 14th, 20069 Muon Events 9 EeV 100 TeV     ~17m

10. SUSY06, June 14th, 200610 NPE Number of photo-electrons (NPE) … an integrated waveform charge divided by single pe charge Correlated with number of photons at source  in-ice particle energy

11. SUSY06, June 14th, 200611 Contained or Uncontained Events with the same energy contained High npe: 10 7 npe uncontained Low npe: 1000 npe ~ 30PeV

12. SUSY06, June 14th, 200612   NPE Energy Distribution E -1 fluxes contained GZK  Atmospheric  GZK  10 7 10 10 [GeV] Log Npe

13. SUSY06, June 14th, 200613 NPE Distribution Distribution difference between the signals and background! Distribution difference between the signals and background! GZK  GZK  Atmospheric 

14. SUSY06, June 14th, 200614 Zenith Angle Distribution Signals peak at horizontal direction Background distribute over down-going region GZK  GZK  Atmospheric  up down

15. SUSY06, June 14th, 200615 Preliminary Event Selection GZK  Atmospheric  GZK 

16. SUSY06, June 14th, 200616 Event Rate with completed detector GZK  0.35 events/year GZK  0.31 events/year Atmospheric  0.033 events/year GZK  GZK  Atmospheric  GZK  GZK  Atmospheric  GZK: S. Yoshida et. al. (1997) ApJ 479:547 (m=4, Zmax=4) IceCube Preliminary

17. SUSY06, June 14th, 200617 GZK  0.13 events/year Atmospheric   0.009 events/year Event Rate: 9 strings and more string numbers 9 20 40 60 80 The same cut for all string numbers GZK  GZK  Atmospheric  9 S 80 S 9 string event rate event rate (integrated) GZK  GZK  Atmospheric  10 7 10 9 [GeV] Rate [/year] IceCube Preliminary

18. SUSY06, June 14th, 200618    Effective Area for EHE signals with completed detector 80 S  up-going horizontal down-going Twice larger charged lepton effective area than physical area for >10 10 GeV IceCube Preliminary

19. SUSY06, June 14th, 200619 How Many Photons Are We Seeing? e Standard-Candle - Photon source with known absolute intensity for each pulse - Photon source with known absolute intensity for each pulse Golden-DOMs - Absolute calibrated DOMs near SC SC on s40 GD on s39 The in-ice energy calibration

20. SUSY06, June 14th, 200620 The Absolute Chain: Standard Candle  Golden DOM SC Known position and shape Known position and shape Nitrogen (337 nm) pulsed laser Nitrogen (337 nm) pulsed laser Cone reflected resembles cascades Cone reflected resembles cascades Pointing-up Pointing-up 1-10 PeV n e cascade equiv. 1-10 PeV n e cascade equiv. GD Absolute calibrated with nitrogen 337 nm laser Absolute calibrated with nitrogen 337 nm laser distance from SC distance from SC 132, 233, 248 m relative angle to SC relative angle to SC -11.9, 56.2, 58.4 deg 130.04m GD SC

21. SUSY06, June 14th, 200621 IceTop: Background Tagging Major background is atmospheric (bundled) muons of which in-ice nature still not well known at this energy regime Major background is atmospheric (bundled) muons of which in-ice nature still not well known at this energy regime Tagging on the surface muons with surface array for an additional information Tagging on the surface muons with surface array for an additional information EHE CR    A real event example (E~ 100TeV-10 PeV)

22. SUSY06, June 14th, 200622 Conclusion -outlook- The largest multi-string neutrino detector! The largest multi-string neutrino detector! IceCube is capable of EHE neutrino search with this year’s configuration and the capability is growing with its string array IceCube is capable of EHE neutrino search with this year’s configuration and the capability is growing with its string array The first-level EHE event selection from BG can be achieved using measured number of photo-electrons The first-level EHE event selection from BG can be achieved using measured number of photo-electrons Energy and geometry reconstruction incl. that of uncontained events, technique using photon propagation information in ice (waveforms) to come Energy and geometry reconstruction incl. that of uncontained events, technique using photon propagation information in ice (waveforms) to come Power of subsystems – calibration and background rejection Power of subsystems – calibration and background rejection

23. SUSY06, June 14th, 2006 23 Backup slides

24. SUSY06, June 14th, 200624 Extremely High Energy Neutrino Targets benchmarking model GZK: S. Yoshida et. al. (1997) ApJ 479:547 (m=4, Zmax=4) TD: Sigl et. al.(1999), UHE 2K : S.Yoshida et al.(1998), AGN Jet: K.Mannheim (1995)

25. SUSY06, June 14th, 200625 MC Setup Benchmarking models Benchmarking models GZK muon and tau signals GZK muon and tau signals Atmospheric muon background (no bundle) Atmospheric muon background (no bundle) muon and tau propagation starts from outside of detection volume muon and tau propagation starts from outside of detection volume Event energy range < GeV Event energy range 10 5 < E < 10 11 GeV E -1 and E -2 fluxes (~10k events each)

26. SUSY06, June 14th, 200626 Effective Area: toward 80 strings  : 10 11 GeV 9 S 80 S in-ice  10 8 GeV up-going horizont al down- going in-ice  10 8 GeV  : 10 11 GeV Effective area enlarged with string numbers for every event direction 10 8 GeV10 11 GeV 0.2~0.4 km 2 0.65~0.9 km 2  0.02~0.15 km 2 0.45~0.78 km 2 9 string effective area IceCube Preliminary