Related papers: Loop Quantum Gravity and Ultra High Energy Cosmic …
Ultra-high cosmic rays (UHECRs) with energies >10^19 eV emitted at cosmological distances will be attenuated by cosmic microwave and infrared background radiation through photohadronic processes. Lower energy extra-galactic cosmic rays…
In this study, we investigated the anisotropy of diffusive Ultra-High Energy Cosmic Rays (UHECRs) by employing three cosmological models: two models from the $f(R, T)$ gravity theory and the other is the standard $\Lambda$CDM model. The…
Previous analyses of cosmic rays above 40 EeV observed by the AGASA experiment have suggested that their arrival directions may be clustered. However, estimates of the chance probability of this clustering signal vary from 10^{-2} to…
We investigate the possibility that cosmic rays of energy larger than the Greisen-Zatsepin-Kuzmin cutoff are not nucleons, but a new stable, massive, hadron that appears in many extensions of the standard model. We focus primarily on the…
Arrival directions of cosmic rays with the energy E>4.10^19 eV are analyzed on the basis of the Yakutsk and AGASA extensive air shower arrays. It is supposed that the clusters can be formed as a result of fragmentation of superheavy nuclei.…
The status of the observations of Ultra High Energy Cosmic Rays will be reviewed, focusing on the the latest results of HiRes and Auger observatories. A comprehensive analytical computation scheme to compute the expected UHECR spectrum on…
The fluctuations of $\gamma$ ray families simulated with CORSIKA in the energy region 3$\times10^{15}-10^{17}$eV on the basis of standard $Ln s$ collider physics exhibits alignments of secondaries in the stratosphere and at ground level.…
The majority of the highest energy cosmic rays are thought to be electrically charged: protons or nuclei. Charged particles experience angular deflections as they pass through galactic and extra-galactic magnetic fields. As a consequence…
We explore scenarios where the highest energy cosmic rays (HECR) are produced by new particle physics near the grand unification scale. Using detailed numerical simulations of extragalactic cosmic and gamma-ray propagation, we show the…
We will review the main physical aspects of Ultra High Energy Cosmic Rays. We will discuss in particular their propagation through astrophysical backgrounds, focusing on the latest experimental observations of HiRes, Telescope Array and…
Space-based experiments, either orbiting the Earth or from scientific balloon altitudes, measure high-energy cosmic rays by measuring from above the atmosphere the optical and radio signals generated by extensive air showers (EAS). These…
Gamma-ray bursts (GRBs) are widely suggested as potential sources of ultrahigh-energy cosmic rays (UHECRs). The kinetic energy of the jets dissipates, leading to the production of an enormous amount of $\gamma$-ray photons and possibly also…
We consider various classes of persistent extragalactic astrophysical sources which have been suggested in literature as possible emitters of ultra-high-energy cosmic rays (UHECR). We compare the strength of the claimed correlations by a…
The observed fluxes of cosmic rays and gamma rays are used to infer the maximum allowed high-energy neutrino flux allowed for Gamma Ray Bursts (GRBs), following Mannheim, Protheroe, and Rachen (2000). It is shown that if GRBs produce the…
The XVII International Symposium on Very High Energy Cosmic Ray Interactions, held in August of 2012 in Berlin, was the first one in the history of the Symposium, where a plethora of high precision LHC data with relevance for cosmic ray…
In recent years the Fly's Eye and Akeno groups have presented analyses of the cosmic ray mass composition at energies above 10^17 eV. While the analysis of the Fly's Eye group points to a likely change in mass composition from heavy to…
We shortly discuss several astrophysical scenarios leading to cosmic ray acceleration up to extremely high energies reaching the scale of 10^{20} eV. The processes suggested in the literature include acceleration at relativistic jet…
This is a written version of a series of lectures aimed at graduate students in astrophysics/particle theory/particle experiment. In the first part, we explain the important progress made in recent years towards understanding the…
An anisotropy signal for the arrival directions of ultra-high energy cosmic rays (UHECR) of more than 99% confidence level was established using data collected by the Pierre Auger Observatory. Cosmic rays with energy above $\sim 6 \times…
The two-point autocorrelation function of ultra-high energy cosmic ray (UHECR) arrival directions has a broad maximum around 25 degrees, combining the data with energies above $4\times 10^{19}$ eV (in the HiRes energy scale) of the HiRes…