2 research outputs found
Ultra High Energy Cosmic Rays
The current status of Ultra High Energy Cosmic Rays (UHECR) is reviewed, with
emphasis given to theoretical interpretation of the observed events. The
galactic and extragalactic origin, in case of astrophysical sources of UHE
particles, have the problems either with acceleration to the observed energies
or with the fluxes and spectra. Topological defects can naturally produce
particles with energies as observed and much higher, but in most cases fail to
produce the observed fluxes. Cosmic necklaces and monopole-antimonopole pairs
are identified as most plausible sources, which can provide the observed flux
and spectrum. The relic superheavy particles are shown to be clustering in the
Galactic halo, producing UHECR without Greisen-Zatsepin-Kuzmin cutoff. The
Lightest Supersymmetric Particles are discussed as UHE carriers in the
Universe.Comment: 10 pages text, 6 ps figures, 1 jpeg figure. Invited talk at TAUP-9
Ultra High Energy Cosmic Rays from Cosmological Relics
The current status of origin of Ultra High Energy Cosmic Rays (UHECR) is
reviewed, with emphasis given to elementary particle solutions to UHECR
problem, namely to Topological Defects and Super-Heavy Dark Matter (SHDM)
particles. The relic superheavy particles are very efficiently produced at
inflation. Being protected by gauge discrete symmetries, they can be long
lived. They are clustering in the Galactic halo, producing thus UHECR without
Greisen-Zatsepin-Kuzmin cutoff. Topological Defects can naturally produce
particles with energies as observed and much higher, but in most cases fail to
produce the observed fluxes. Cosmic necklaces, monopoles connected by strings
and vortons are identified as most plausible sources. The latter two of them
are also clustering in the halo and their observational predictions are
identical to those of SHDM particles.Comment: Invited talk at TAUP-99, Paris, September 6 - 10, 1999. Several
references are adde