EHE Lepton Propagation in the Earth and Its Implications to the IceCube EHE  Propagation in the Earth EHE  Propagation in the Earth What is the GZK mechanism? What is the GZK mechanism? Expected intensities at the IceCube depth Expected intensities at the IceCube depth Atmospheric  – background Atmospheric  – background Event rate Event rate IceCube EHE  sensitivity IceCube EHE  sensitivity Mons 2003 Shigeru Yoshida Chiba University

UHE (EeV or even higher) Neutrino Events Arriving Extremely Horizontally Needs Detailed Estimation Limited Solid Angle Window (  N A ) -1 ~ 600 (  / cm 2 ) -1 (  /2.6g cm -3 ) -1 [km] Involving the interactions generating electromagnetic/hadron cascades NN  X e + e - Mons 2003

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

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

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!!

Mons 2003 Yoshida and Teshima 1993 Yoshida, Dai, Jui, Sommers 1997

Mons 2003

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

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

Mons 2003 Down-going events dominate… 1400 m 2800 m 11000m UpDown Atmospheric  is attenuated faster…

Mons 2003

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

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

Mons 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 ]

IceCube EHE Sensitivity 90% C.L. for 10 year observation

Mons 2003 Conclusion  appeared in 10 PeV- EeV are our prime target on GZK detection. 1/1000 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….

This Simulator is Open to the IceCube Collaboration. JULIET ver1 (Java-based Ultrahigh-energy Lepton Integral Transporter) e /  /  /  /  Propagator in rock/ice at EHEs (PeV or greater) by numerically calculating the transport equations e /  /  /  /  Propagator in rock/ice at EHEs (PeV or greater) by numerically calculating the transport equations e /  /  /  /  Monte Carlo Event Generator (ignoring the ionization loss) from 100 TeV- 1ZeV e /  /  /  /  Monte Carlo Event Generator (ignoring the ionization loss) from 100 TeV- 1ZeV Downloadable from Downloadable fromwww-ppl.s.chiba-u.jp/research/IceCube/eheSim/ Users Manual will be released within a few months Users Manual will be released within a few months

Backup slides

IceCube 1400 m 2400 m AMANDA South Pole IceTop Skiway 80 Strings 80 Strings 4800 PMT 4800 PMT Instrumented volume: 1 km3 (1 Gt) Instrumented volume: 1 km3 (1 Gt) IceCube is designed to detect neutrinos of all flavors at energies from 10 7 eV (SN) to eV IceCube is designed to detect neutrinos of all flavors at energies from 10 7 eV (SN) to eV

Mons 2003 Cross Sections and the Energy Loss Term CTEQ5 Parton Distribution for the evaluation

Mons 2003

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