Related papers: Hadron-gamma discrimination from an orbital UHECR …
The field of ultra-high energy cosmic rays made a lot of progresses last years with large area experiments such as the Pierre Auger Observatory, HiRes and the Telescope Array. A suppression of the cosmic ray flux at energies above…
Interactions of ultra-high energy cosmic rays (UHECRs) accelerated in specific astrophysical environments have been shown to shape the energy production rate of nuclei differently from that of the secondary neutrons escaping from the…
We propose a method to extract high-energy hadronic interaction properties from the distributions of two of the main observables of proton extensive air showers: the depth of maximum shower development, $X_\mathrm{max}$, and the number of…
Cosmic-rays with energies exceeding 10^{19} eV are referred to as Ultra High Energy Cosmic Rays (UHECRs). The sources of these particles and their acceleration mechanism are unknown, and for many years have been the issue of much debate.…
Ultra high energy (UHE) photons can initiate electromagnetic showers in magnetic field. We analyze the two processes that determine the development of the shower, $e^+ e^-$ pair creation and synchrotron radiation, and derive formulae for…
Production of ultra-high-energy (UHE) particles in astrophysics should not be different from the hadron production at the contemporary proton colliders. LHC experiments are providing us with the proton spectra at very high energy (VHE) that…
In the present work we carry out a study of the high energy cosmic rays mass identification capabilities of a hybrid detector employing both fluorescence telescopes and particle detectors at ground using simulated data. It involves the…
JEM-EUSO is a space science mission to explore extreme energies and physics of the Universe. Its instrument will watch the dark-side of the earth and will detect UV photons emitted from the extensive air shower caused by an Ultra-High…
From deflections in galactic and extragalactic magnetic fields energy dependent structures in the arrival directions of ultra-high energy cosmic rays (UHECR) are expected. We propose to characterize these structures by the strength of…
We study the production of cosmogenic neutrinos and photons during the extragalactic propagation of ultra-high-energy cosmic rays (UHECRs). For a wide range of models in cosmological evolution of source luminosity, composition and maximum…
The High-Altitude Water Cherenkov experiment (HAWC) observatory is located 4100 meters above sea level. HAWC is able to detect secondary particles from extensive air showers (EAS) initiated in the interaction of a primary particle (either a…
Background showers triggered by hadrons represent over 99.9% of all particles arriving at ground-based gamma-ray observatories. An important stage in the data analysis of these observatories, therefore, is the removal of hadron-triggered…
The HiRes and AGASA Collaborations have published contradictory energy spectra for energies above the GZK cut-off. In this article, we investigate the acceptance of fluorescence telescopes to different primary particles at the highest…
The energy density of the Ultra High Energy Cosmic Rays (UHECR) in the Universe is a very important parameter for the solution of the puzzle of their origin. It defines the luminosity of the UHECR sources and thus the type of objects they…
JEM-EUSO is a mission to study ultra-high-energy cosmic rays (UHECRs) by measuring the fluorescence light from giant air showers at the altitude of the International Space Station. In the tilted mode, JEM-EUSO will become very sensitive to…
We discuss that hadron-induced atmospheric air showers from ultra-high energy cosmic rays are sensitive to QCD interactions at very small momentum fractions x where nonlinear effects should become important. The leading partons from the…
We explore particle physics beyond accelerator energies, motivated by questions exposed in astroparticle physics observations: 1) Are there reasonable modifications to the standard extrapolations of LHC-tuned hadronic interaction models, so…
The understanding of the nature of ultra-high-energy cosmic rays is one of the most intriguing open questions for current and future observatories. These particles are expected to be accelerated in extragalactic sources. Because of their…
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…
The origin of ultra-high energy cosmic rays (UHECRs) and neutrinos is still a mystery. Hadronic acceleration theory suggests that they should originate in the same sources (astrophysical or cosmological), together with gamma-rays. While…