Related papers: Loop Quantum Gravity and Ultra High Energy Cosmic …
Contrary to expectations, several cosmic ray events with energies above $10^{20}$ eV have been observed. The flux of such events is well above the predicted Greisen-Zatsepin-Kuzmin cutoff due to the pion production (via the $\Delta$…
Cosmic rays from outer space enter the atmosphere with energies of up to 10^{11} GeV. The initial particle or a secondary hadron inside the shower may then interact with an air nucleon to produce nonstandard particles. In this article we…
The year 2007 has furnished us with outstanding results about the origin of the most energetic cosmic rays: a flux suppression as expected from the GZK-effect has been observed in the data of the HiRes and Auger experiments and correlations…
The HiRes Collaboration has recently announced preliminary measurements of the energy spectrum of ultra-high energy cosmic rays (UHECR), as seen in monocular analyses from each of the two HiRes sites. This spectrum is consistent with the…
We have proposed that the cosmic ray spectrum "knee", the steepening of the cosmic ray spectrum at energy $E \gsim 10^{15.5}$ eV, is due to "new physics", namely new interactions at TeV cm energies which produce particles undetected by the…
We study the proposal that the cosmic ray primaries above the Greisen-Zatsepin-Kuzmin (GZK) cutoff are gluino-containing hadrons ($\tilde g$-hadrons). We describe the interaction of $\tilde g$-hadrons with nucleons in the framework of the…
With the Akeno Giant Air Shower Array (AGASA), 581 cosmic rays above 10^19eV, 47 above 4 x 10^19eV, and 7 above 10^20eV are observed until August 1998. Arrival direction distribution of these extremely high energy cosmic rays has been…
The High Resolution Fly's Eye Experiment (HiRes) measures cosmic rays (CR) at the highest energies using the air fluorescence technique. As data taking on the Dugway Proving Grounds in Western Utah is finished, the HiRes data are relevant…
We consider the propagation of ultra high energy cosmic rays through turbulent magnetic fields and study the transition between the regimes of single and multiple images of point-like sources. The transition occurs at energies around…
A new method to derive an upper limit on photon primaries from small data sets of air showers is developed which accounts for shower properties varying with the primary energy and arrival direction. Applying this method to the…
We reanalyse the prospects for upcoming Ultra-High Energy Cosmic Ray experiments in connection with the phenomenology of Super-heavy Dark Matter. We identify a set of observables well suited to reveal a possible anisotropy in the High…
We present numerical simulations on the propagation of UHE protons with energies of $(10^{19.5}-10^{22})$ eV in extragalactic magnetic fields over 1 Gpc. We use the ORS galaxy sample, which allow us to accurately quantify the contribution…
The paper describes methods used for the detection of cosmic rays with energies above 10^18 eV (UHECR, UltraHigh Energy Cosmic Rays). It had been anticipated there would be a cutoff in the energy spectrum of primary cosmic rays around 3…
Gamma-ray bursts (GRBs) have long been considered as candidates of ultrahigh-energy cosmic rays (UHECRs). We investigate the signatures of CR proton acceleration in the GRBs by consistently taking into account their hadronic and…
Ultra-high energy photons constitute one of the most important pieces of the astroparticle physics problems. Their observation may provide new insight on several phenomena such as supermassive particle annihilation or the GZK effect.…
In the first part of this review we discuss the basic observational features at the end of the cosmic ray energy spectrum. We also present there the main characteristics of each of the experiments involved in the detection of these…
In a recent letter [1] with the same title, Farrar and Piran offered an explanation for the near isotropy of the arrival directions [2] of ultrahigh energy cosmic rays (UHECRs) and the apparent absence [3] of the so called `GZK cutoff' in…
This is an introductory review about the on-going search for a signal of Lorentz Invariance Violation (LIV) in cosmic rays. We first summarise basic aspects of cosmic rays, focusing on rays of ultra high energy (UHECRs). We discuss the…
In the last years a general consensus has emerged on the use of ultra-high energy cosmic rays (UHECR) data as a powerful probe of the validity of special relativity. This applies in particular to the propagation of cosmic rays from their…
Arrival directions of cosmic rays with the energy E>4.10^{19} eV are analyzed by using data of the Yakutsk and AGASA (Japan) extensive air showers (EAS) arrays. It is supposed that the clusters can be formed as a result of decay of…