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Unraveling UHE Neutrinos: Crucial Clues to Cosmic Ray Origins

Explore the significance of >1019eV neutrinos in identifying cosmic ray sources, avoiding absorption, and probing CR accelerators. Learn about energy conversion in sources, spectral cutoffs, and identifying UHECR sources. Discover the implications of EeV neutrinos and essential detection methods.

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Unraveling UHE Neutrinos: Crucial Clues to Cosmic Ray Origins

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  1. 1018eV Neutrinos associated with UHECR (>1019eV) sources Zhuo Li (黎卓) Peking University, Beijing Collaborators:Eli Waxman & Liming Song Li & Waxman, arXiv:0711.4969

  2. Why EeV neutrino • To directly identify CR sources • Neutrino • Pointing to the source • Avoiding absorption • 1018eV • Primary >1019eV

  3. HE Neutrinos from CR accelerators • -production in accelerators: • acc. p’s; acc. e’s : synchrotron/IC photons • If all p energy converted to  (in the source) • Waxman-Bahcall Bound for sources optically thin to p: Waxman & Bahcall 1999

  4. UHECR source: acceleration

  5. GRB HE n’s: pg interaction p+→ m+ + nm (~10-8s) m+→ e+ + ne+ nm(~10-6s) _ e=0.05ep eg ep=0.2GeV2G2 • D-resonance: • eg~1 MeV en~1014eV.

  6. Spectral cutoff: EM cooling • For >10PeV protons, the fraction of total energy loss • Suppressed by pi+/mu+ EM energy loss • life, tcool1/ en2n(en) f=0.2 [Waxman & Bahcall 1997] ~1PeV 100TeV Neutrino energy No UHE neutrinos, how to identify UHECR sources? [Kashiti & Waxman 2005; Rachen & Meszaros 1998]

  7. EeV neutrinos: 0-induced en2n WB bound: f=1 f=0.2 No cooling suppression; 3% WB bound Prompt ~10sec 100TeV 1PeV 1EeV en

  8. HE ’s from neutral 0 production p0 • Processes g CMB EM cooling suppression m n no cooling suppression [Li & Waxman 2007b]

  9. q n lm g CMB peak n+2 • Q1: suppressed by e+- production? • Q2: deflected by IGM field (hence delayed)? cross section -1, similar above  threshold e+- thr. +-thr. =1019-20eV, /e=(3-10)% [Li & Waxman 2007b]

  10. Q3: HE ’s escape from source? • Attenuated by e+- production in source • low energy break • KN suppression of cross section • Strong synchrotron absorption below keV • Conclusion: >10PeV photons don’t suffer attenuation dn/de [Li & Waxman 2007b] ~1MeV ~1keV e [Li & Waxman 2007a] [Li & Song 2004]

  11. EeV neutrinos: a new channel en2n WB bound 1 0.2 20/km2yr 1km2 experiment 0.03 100TeV 1PeV 1EeV en n-g association (time/direction): directly identify sources [Li & Waxman 2007b]

  12. Coherence radio Cerenkov: • ANITA (balloon) • ARIANNA (array) • ~1/yr expected [Barwick 2007]

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