We measure the correlation between sky coordinates of the Swift BAT catalogue of active galactic nuclei with the arrival directions of the highest energy cosmic rays detected by the Auger Observatory. The statistically complete, hard X-ray catalogue helps to distinguish between AGN and other source candidates that follow the distribution of local large-scale structure. The positions of the full...

We present results of numerical simulations of the propagation of ultra high energy cosmic rays (UHECRs) over cosmological distances, aimed at quantifying the statistical significance of the highest energy data on the spectrum and small scale anisotropies as detected by the AGASA experiment. We assess the significance of the lack of a GZK feature and its compatibility with the reported small sc...

We calculate low scale gravity effects on the cross section for neutrino-nucleon scattering at center of mass energies up to the Greisen-Zatsepin-Kuzmin (GZK) scale, in the eikonal approximation. We compare the cases of an infinitely thin brane embedded in n = 5 compactified extra-dimensions, and of a brane with a physical tension MS = 1 TeV and MS = 10 TeV. The extra dimensional Planck scale M...

Decaying superheavy particles can be produced by Topological Defects or, in case they are quasistable, as relics from the early Universe. The decays of these particles can be the sources of observed Ultra High Energy Cosmic Rays (E ∼ 10 − 10 GeV ). The Topological Defects as the UHE CR sources are critically reviewed and cosmic necklaces and monopole-antiminopole pairs are identified as most pl...

A simple model of a homogeneous population of cosmic accelerators injecting protons following a unique power law has long been shown to fit the HiRes monocular data very well. The model evolves the sources with redshift and adjusts both the redshift evolution and the exponent in the injecting power law to fit the data. At lower energies galactic iron is added in as suggested by composition meas...

We study the proposal that the cosmic ray primaries above the Greisen-ZatsepinKuzmin (GZK) cutoff are gluino-containing hadrons (g̃-hadrons). We describe the interaction of g̃-hadrons with nucleons in the framework of the Gribov-Regge approach using a modified version of the hadronic interaction model QGSJET for the generations of Extensive Air Showers (EAS). There are two mass windows marginally...

In interactions of ultra-high-energy cosmic ray (UHECR) protons with microwave background photons, we focus in this work on photopion production reactions and the effects measured, broad, energy-loss distributions these evolution protons' density functions energy space. We rely a Fokker–Planck transport equation space whose coefficients are calculated using laboratory measurements. also derive ...