GZK EHE detection What is the GZK mechanism? EHE  Propagation in the Earth Expected intensities at the IceCube depth Atmospheric  – background Event rate TAUP 2003

GZK Neutrino Production K 411 photons / cm x cm 2 γ p n p π ＋ μ ＋ ν e ＋ ν γ E = eV E 0.8 x eV ~ Conventional Mechanism of EHE neutrinos!!

TAUP 2003 Yoshida and Teshima 1993 Yoshida, Dai, Jui, Sommers 1997 Note: The oscillations convert e,  to e, , 

TAUP 2003  /  propagation in Earth

e e      e/     Weak Incoming Products Weak Cascades Decay Weak Pair/decay Bremss Pair PhotoNucl. Decay Pair Pair Bremss Decay Weak Decay

TAUP 2003 Tau(Neutrinos) from    Suppression By  decay Muon(Neutrinos) from   Nadir Angle

１．４ ｋｍ １ｋｍ Upward Ice Rock ν ± π γ ν + e － e １ｋｍ Downward ν γ γ + e － e lepton

TAUP 2003 Upward-goingDownward going!! Atmospheric muon! – a major backgrond But so steep spectrum

TAUP 2003 Down-going events dominates… 1400 m 2800 m 11000m UpDown Atmospheric  is strongly attenuated…

Flux as a function of energy deposit in km 3 dE/dX~  E  E~  XbE

TAUP 2003 UpDown

TAUP 2003 Intensity of EHE  and  GZK m=4 Z max =4 I  (E>10PeV)I  (E>10PeV) RATE [/yr/ km 2 ] Down Up I  (E>10PeV) Energy Deposit I  (E>10PeV) Energy Deposit Down m=7 Z max =5 Down Atm  [cm -2 sec -1 ]

E µ =10 TeV ≈ 90 hitsE µ =6 PeV ≈ 1000 hits How EHE events look like The typical light cylinder generated by a muon of 100 GeV is 20 m, 1PeV 400 m, 1EeV it is about 600 to 700 m.

TAUP 2003 Conclusion  appeared in 10 PeV- EeV are our prime target on GZK detection. 1/100-1/500 of primary  intensity! Downward  and  make main contributions in PeV -EeV Energy Estimation would be a key for the bg reduction Because atmospheric  spectrum ~ E -3.7 GZK is DETECTABLE by IceCube events/year (BG 0.05 events/year) IceCube has great capability for TeV-PeV -induced muons taking advantage of long range in the clear ice. For EHE like the GZK….