出版社:SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要:The origin of highest energy cosmic rays (UHECR) is yet unknown. In order
to understand their propagation we determine the probability that an ultrahigh energy
(above 5 1019 eV) proton created at a distance r with energy E arrives at earth above
a threshold Ec. The clustering of ultrahigh energy cosmic rays suggests that they might
be emitted by compact sources. A statistical analysis on the source density based on
the multiplicities is presented. The ultrahigh energy cosmic ray spectrum is consistent
with the decay of GUT scale particles. Alternatively, we consider the possibility that a
large fraction of the ultrahigh energy cosmic rays are decay products of Z bosons which
were produced in the scattering of ultrahigh energy cosmic neutrinos on cosmological relic
neutrinos. Based on this scenario we determine the required mass of the heaviest relic
neutrino. The required ultrahigh energy neutrino flux should be detected in the near
future by experiments such as AMANDA, RICE or the Pierre Auger Observatory.