neutrinos and z-bursts dmitry semikoz ucla (los angeles) & inr (moscow)

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Neutrino Oscillation Workshop, September 11-17, 2004 The Greisen-Zatsepin-Kuzmin (GZK) effect Nucleons can produce pions on the cosmic microwave background nucleon   -resonance multi-pion production pair production energy loss pion production energy loss pion production rate  sources must be in cosmological backyard within Mpc from Earth (compare to the Universe size ~ 5000 Mpc)

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Neutrinos and Z-bursts Dmitry Semikoz UCLA (Los Angeles) & INR (Moscow) Neutrino Oscillation Workshop, September 11-17, 2004 Overview Introduction: Z-burst model: general idea Problem of gamma-ray flux Production of UHECR neutrinos Neutrino mass and Z-burst Experimental limits on neutrino flux Conclusions Neutrino Oscillation Workshop, September 11-17, 2004 The Greisen-Zatsepin-Kuzmin (GZK) effect Nucleons can produce pions on the cosmic microwave background nucleon -resonance multi-pion production pair production energy loss pion production energy loss pion production rate sources must be in cosmological backyard within Mpc from Earth (compare to the Universe size ~ 5000 Mpc) Neutrino Oscillation Workshop, September 11-17, 2004 AGASA and HiRes experiments HiRes: astro-ph/ AGASA: astro-ph/ Neutrino Oscillation Workshop, September 11-17, 2004 Z-burst mechanism Resonance energy E = (1 eV/m ) eV Cross section Works for UHECR only if m eV T.Weiler, 1982 D.Fargion, B.Mele and A.Salis 1997; T.Weiler, 1997 Neutrino Oscillation Workshop, September 11-17, 2004 Cross sections for neutrino interactions with relict background and Neutrino Oscillation Workshop, September 11-17, 2004 Z-burst mechanism Average cross section Relic neutrino density Mean free path of neutrino is L = 150 Gpc >> L univ T.Weiler, 1982 D.Fargion, B.Mele and A.Salis 1997; T.Weiler, 1997 Neutrino Oscillation Workshop, September 11-17, 2004 Problem of secondary gamma-ray flux Neutrino Oscillation Workshop, September 11-17, 2004 The high energy gamma ray detector on the Compton Gamma Ray Observatory (20 MeV - ~20 GeV) EGRET: diffuse gamma-ray flux Neutrino Oscillation Workshop, September 11-17, 2004 Problem: too high diffuse - ray flux m 1 eV (Yoshida,Sigl,Lee,1998) Neutrino Oscillation Workshop, September 11-17, 2004 Possible solution: local overdensity but at least factor 20 over 5 Mpc is needed Here factor 100 over 20 Mpc Neutrino Oscillation Workshop, September 11-17, 2004 Neutrino overdensity in galaxy clusters S.Singh, C-P.Ma, Phys.Rev.D 67, (2003) Neutrino Oscillation Workshop, September 11-17, 2004 Non-uniform distribution of sources Kalashev, Kuzmin, D.S. and Sigl, hep-ph/ Neutrino Oscillation Workshop, September 11-17, 2004 Production of UHE neutrinos Neutrino Oscillation Workshop, September 11-17, 2004 Neutrinos from pion production in sources p n Conclusion: photon and neutrino fluxes from pion production are connected in well-defined way. If we know one of them we can predict other one. Neutrino Oscillation Workshop, September 11-17, 2004 Sources of both and O.Kalashev, V.Kuzmin, D.S. and G.Sigl, hep-ph/ Neutrino Oscillation Workshop, September 11-17, 2004 X -> only (Gelmini-Kusenko, 2001) Secondary gamma-ray flux in production just 10% of neutrino flux V.Berezinsky, M.Kachelriess and S.Ostapchenko, hep-ph/ Neutrino Oscillation Workshop, September 11-17, 2004 Neutrino mass? Neutrino Oscillation Workshop, September 11-17, 2004 Can we define neutrino mass? Yes ( Z.Fodor, S.Katz andA.Ringwald, hep-ph/ ) Neutrino Oscillation Workshop, September 11-17, 2004 Dependence from m equally good fit at any mass. m =0.1 eV m =1 eV Many free parameters: source distribution, magnetic field, radio background Neutrino Oscillation Workshop, September 11-17, 2004 Dependence on radio background equally good fit at any mass. Z.Fodor, S.Katz and A.Ringwald, hep-ph/ Neutrino Oscillation Workshop, September 11-17, 2004 Experimental constraints on UHE neutrinos Neutrino Oscillation Workshop, September 11-17, 2004 e + n p + e - e - ... cascade relativist. pancake ~ 1cm thick, ~10cm each particle emits Cherenkov radiation C signal is resultant of overlapping Cherenkov cones for >> 10 cm (radio) coherence C-signal ~ E 2 nsec negative charge is sweeped into developing shower, which acquires a negative net charge Q net ~ 0.25 E cascade (GeV). Threshold > eV Experiments: GLUE, RICE, FORTE Neutrino Oscillation Workshop, September 11-17, 2004 Goldstone Lunar UHE Neutrino Search (GLUE) P. Gorham et al., PRL 93, (2004) Two antennas at JPLs Goldstone, Calif. Tracking Station l limits on >10 20 eV s l regolith atten. len. ~20 m l ~123 hours livetime l [V ] eff ~600 km 3 -sr l datataking complete Earlier experiment: 12 hrs using single Parkes 64m dish in Australia: T. Hankins et al., MNRAS 283, 1027 (1996) Neutrino Oscillation Workshop, September 11-17, 2004 FORTE satellite (Fast On-orbit Recording of Transient Events) Main mission: synaptic lightning observation Viewed Greenland ice with appropriate trigger ( ) 1.9 MILLION km 3 38 days 6% Can self-trigger on transient events in 22MHz band in VHF band (from 30 to 300 MHz) Event characterization polarization ionospheric group delay and birefringence timing Log-periodic antennas N. Lehtinen et al., PRD 69, (2004) Neutrino Oscillation Workshop, September 11-17, 2004 FORTE Neutrino Oscillation Workshop, September 11-17, 2004 GLUE, FORTE and WMAP strongly disfavor Z-burst model D.S. and G.Sigl, hep-ph/ Neutrino Oscillation Workshop, September 11-17, 2004 ANITA An tarctic I mpulsive T ransient A rray Flight in 2006 Neutrino Oscillation Workshop, September 11-17, 2004 ANITA will rule out (confirm???) Z-burst model ANITA Neutrino Oscillation Workshop, September 11-17, 2004 CONCLUSIONS Z-burst model can explain UHECR above GZK cutoff, but produce large gamma-ray flux. One can not define neutrino mass from this model: too many unknown parameters. This model is strongly disfavored by limits on neutrino flux from GLUE and FORTE experiments combined with cosmological bound on neutrino mass. Finally this model will be tested in by ANITA experiment.