Neutrino astronomy and massive longlived particles from big bang

Jul, 1991
29 pages
Published in:
  • Nucl.Phys.B 380 (1992) 478-506
  • Published: 1992
Report number:
  • LNGS-91-02

Citations per year

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Abstract: (Elsevier)
We consider the neutrino flux from the decay of long-lived big-bang particles. The red-shift z tr at which the neutrino transparency of the universe sets in is calculated as a function of neutrino energy: z tr ≅ 1 × 10 5 for TeV neutrinos and z tr ≅ 3 × 10 6 for 10 MeV neutrinos. One might expect the production of detectable neutrino flux at z ⪅ z tr , but, as demonstrated in this paper, the various upper limits, most notably due to nucleosynthesis and diffuse X- and gamma-rays, preclude this possibility. Unless the particle decay is strongly dominated by the pure neutrino channel, observable neutrino flux can be produced only at the current epoch, corresponding to red-shift z ≈ 0. For the thermal relics which annihilate through the gauge bosons of SU(3)×SU(2)×U(1) group, the neutrino flux can be marginally detectable at 0.1 < E v < 10 TeV. As an example of non-thermal relics we consider gravitinos. If gravitinos are the lightest supersymmetric particles (LSP) they can produce the detectable neutrino flux in the form of a neutrino line with energy E v = 1 2 M G , where M G is the gravitino mass. The flux strongly depends on the mechanisms of R -parity violation. It is shown that heavy gravitinos ( M G ⪅ 100 GeV) can make up the dark matter in the universe.
  • neutrino: cosmic radiation
  • neutrino: flux
  • flux: neutrino
  • energy dependence
  • upper limit
  • cosmological model
  • neutrino neutrino: elastic scattering
  • elastic scattering: neutrino neutrino
  • photon: cosmic radiation
  • cosmic background radiation