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TAUP 2003. GZK EHE n detection. What is the GZK mechanism? EHE n/m/t Propagation in the Earth Expected intensities at the IceCube depth Atmospheric m – background Event rate. GZK Neutrino Production. 0.6 x 10 -27 cm 2. 2.725 K. 411 photons / cm 3. π. ν. +. +. γ. μ. +. ν. e.
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TAUP 2003 GZK EHEn detection • What is the GZK mechanism? • EHE n/m/t Propagation in the Earth • Expected intensities at the IceCube depth • Atmospheric m – background • Event rate
GZK Neutrino Production 0.6 x 10-27 cm2 2.725 K 411 photons / cm3 π ν + + γ μ + ν e p γ p n E = 10 20 eV Conventional Mechanism of EHE neutrinos!! E 0.8 x 10 20 eV ~
Note: The oscillations convert ne, nm to ne,nm, nt Yoshida and Teshima 1993 Yoshida, Dai, Jui, Sommers 1997 TAUP 2003
t/m propagation in Earth TAUP 2003
Products ne nm nt m t p e/g ne Weak Weak nm Weak Weak nt Weak Weak Incoming e/g Cascades Decay Weak Pair/decay Bremss Decay m Pair Pair PhotoNucl. DecayPair Decay Pair Bremss Decay Decay Weak t Pair PhotoNucl. p Cascades
Suppression By t decay Muon(Neutrinos) from nm nt Tau(Neutrinos) from nm nt Nadir Angle TAUP 2003
ν Downward lepton γ γ ± π + + e e - - e e 1.4km 1km Ice γ ν lepton 1km Rock ν Upward
Atmospheric muon! – a major backgrond But so steep spectrum Upward-going Downward going!! TAUP 2003
11000m 2800 m 1400 m Down-going events dominates… Atmospheric m is strongly attenuated… Up Down TAUP 2003
Flux as a function of energy deposit in km3 • dE/dX~bE DE~DXbE
Up Down TAUP 2003
Intensity of EHE m and t [cm-2 sec-1] TAUP 2003
How EHE events look like Eµ=10 TeV ≈ 90 hits Eµ=6 PeV ≈ 1000 hits 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.
Conclusion t/m appeared in 10 PeV- EeV are our prime target on GZK n detection. 1/100-1/500 of primary n intensity! Downwardt and m make main contributions in PeV -EeV Energy Estimation would be a key for the bg reduction Because atmospheric m spectrum ~ E-3.7 TAUP 2003 IceCube has great capability for TeV-PeV n-induced muons taking advantage of long range in the clear ice. For EHE n like the GZK…. GZK n is DETECTABLE by IceCube 0.2-40 events/year (BG 0.05 events/year)