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EHE Lepton Propagation in the Earth and Its Implications to the IceCube

EHE Lepton Propagation in the Earth and Its Implications to the IceCube. EHE n/m/t Propagation in the Earth What is the GZK mechanism? Expected intensities at the IceCube depth Atmospheric m – background Event rate IceCube EHE n sensitivity. Shigeru Yoshida Chiba University.

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EHE Lepton Propagation in the Earth and Its Implications to the IceCube

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  1. EHE Lepton Propagation in the Earth and Its Implications to the IceCube • EHE n/m/t Propagation in the Earth • What is the GZK mechanism? • Expected intensities at the IceCube depth • Atmospheric m– background • Event rate • IceCube EHE n sensitivity Shigeru Yoshida Chiba University Mons 2003

  2. UHE (EeV or even higher) Neutrino Events Arriving Extremely Horizontally • Needs Detailed Estimation • Limited Solid Angle Window (srNA)-1 ~ 600 (s/10-32cm2) -1(r/2.6g cm-3) -1 [km] Involving the interactions generating electromagnetic/hadron cascades mN mX e+e- Mons 2003

  3. 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 Decay Decay Weak t Pair PhotoNucl. p Cascades

  4. Suppression By t decay Muon(Neutrinos) from nm nt Tau(Neutrinos) from nm nt Nadir Angle Mons 2003

  5. 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 ~

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

  7. Mons 2003

  8. Atmospheric muon! – a major backgrond But so steep spectrum Upward-going Downward going!! Mons 2003

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

  10. 11000m 2800 m 1400 m Down-going events dominate… Atmospheric m is attenuated faster… Up Down Mons 2003

  11. Mons 2003

  12. Flux as a function of energy deposit in km3 • dE/dX~bE DE~DXbE

  13. Flux as a function of energy deposit in km3 • dE/dX~bE DE~DXbE

  14. Intensity of EHE m and t [cm-2 sec-1] Mons 2003

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

  16. Conclusion t/m appeared in 10 PeV- EeV are our prime target on GZK n detection. 1/1000 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 Mons 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 0.3-40 events/year (BG 0.05 events/year)

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

  18. Backup slides

  19. IceTop AMANDA South Pole Skiway 1400 m 2400 m IceCube • 80 Strings • 4800 PMT • Instrumented volume: 1 km3 (1 Gt) • IceCube is designed to detect neutrinos of all flavors at energies from 107 eV (SN) to 1020 eV

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

  21. Mons 2003

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

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