Cosmic Topological Defects, Highest Energy Cosmic Rays, and the Baryon Asymmetry of the Universe

In the context of string field theory, the possibility exists for the spontaneous violation of Lorentz invariance and CPT. In this talk, we review its status and some experimental constraints. We discuss the possibility that stringy CPT violation could give rise to a mechanism in which baryogenesis occurs in the early Universe in thermal equilibrium and show that this can produce, under suitable circumstances, a baryon asymmetry equal to the observed value.

The highest energy cosmic rays observed possess macroscopic energies and their origin is likely to be associated with the most energetic processes in the Universe. Their existence triggered a flurry of theoretical explanations ranging from conventional shock acceleration to particle physics beyond the Standard Model and processes taking place at the earliest moments of our Universe. Furthermore, many new experimental activities promise a strong increase of statistics at the h...

Cosmic rays have been observed up to energies $10^8$ times larger than those of the best particle accelerators. Studies of astrophysical particles (hadrons, neutrinos and photons) at their highest observed energies have implications for fundamental physics as well as astrophysics. Thus, the cosmic high energy frontier is the nexus to new particle physics. This overview discusses recent advances being made in the physics and astrophysics of cosmic rays and cosmic gamma-rays at...

In this talk I begin with a brief review of the status of approaches to understanding the origin of the baryon asymmetry of the universe (BAU). I then describe a recent model unifying three seemingly-distict problems facing particle cosmology: the origin of inflation, the generation of the BAU and the nature of dark energy.

The origin of cosmic rays is one of the major unresolved astrophysical questions. In particular, the highest energy cosmic rays observed possess macroscopic energies and their origin is likely to be associated with the most energetic processes in the Universe. Their existence triggered a flurry of theoretical explanations ranging from conventional shock acceleration to particle physics beyond the Standard Model and processes taking place at the earliest moments of our Univers...

We conjecture that the highest energy cosmic rays beyond the Greisen-Zatsepin-Kuzmin cut-off may provide a unique window into the very early epoch of the Universe, namely, that of reheating after inflation, provided these cosmic rays are due to decays of parent superheavy long-living X-particles. These particles may constitute a considerable fraction of cold dark matter in the Universe. We argue that the unconventionally long lifetime of the superheavy particles, which shou...

The phase of inflationary expansion in the early universe produces superheavy relics in a mass window between 10^{12} GeV and 10^{14} GeV. Decay or annihilation of these superheavy relics can explain the observed ultrahigh energy cosmic rays beyond the Greisen-Zatsepin-Kuzmin cutoff. We emphasize that the pattern of cosmic ray arrival directions with energies beyond 20 EeV will decide between the different proposals for the origin of ultrahigh energy cosmic rays.

This paper is devoted to the investigation of connection between two apparent asymmetries of the nature --- time-asymmetry and Baryon Asymmetry of the Universe (BAU). The brief review of this subjects is given. We consider the particle behavior in curved space-time and the possibility of $T$- and $CPT$-violation by the universe expansion. If these symmetries are violated we can dispens with the nonequilibrium condition which is usualy considered as the one of necessary ingred...

In this report I summarize contributions on the highest energy cosmic rays to the 28th International Cosmic Ray Conference in Tsukuba, Japan, Sections HE 1.3, 1.4 and 1.5 involved over 80 oral presentations and about 120 posters. This large body of work attests to the vitality of a field committed to resolving the mystery of the origin of ultra-high energy cosmic rays. These cosmic rays with energies well above $10^{18}$ eV are messengers of an unknown extremely high-energy u...

We present a brief introduction to the physics of Ultra High Energy Cosmic Rays (UHECRs), concentrating on the experimental results obtained so far and on what, from these results, can be inferred about the sources of UHECRs.