Related papers: Highest Energy Cosmic Rays
Ultra high energy gamma rays produce electron--positron pairs in interactions on the geomagnetic field. The pair electrons suffer magnetic bremsstrahlung and the energy of the primary gamma ray is shared by a bunch of lower energy…
The highest energy cosmic rays, above the Greisen-Zatsepin-Kuzmin cut-off of cosmic ray spectrum, may be produced in decays of superheavy long-living X-particles. We conjecture that these particles may be produced naturally in the early…
A brief review about the chemical composition of cosmic rays in the energy range 10^15 < E < 10^20 eV is given. While there is convincing evidence for an increasingly heavier composition above the knee, no clear picture has emerged at the…
We demonstrate by numerical flux calculations that neutrino beams producing the observed highest energy cosmic rays by weak interactions with the relic neutrino background require a non-uniform distribution of sources. Such sources have to…
A complete model for the origin of high-energy >~10^{14} eV) cosmic rays from gamma-ray bursts (GRBs) and implications of this hypothesis are described. Detection of high-energy neutrinos from GRBs provide an unambiguous test of the model.…
Cosmic-ray protons with energies above $10^{16}$ eV passing near the Sun may interact with photons emitted by the Sun and be excited to a $\Delta^+$ resonance. When the $\Delta^+$ decays, it produces pions which further decay to muons and…
Very high energy gamma-rays probe the long-standing mystery of the origin of cosmic rays. Produced in the interactions of accelerated particles in astrophysical objects, they can be used to image cosmic particle accelerators. A first…
We investigate the proposal that primary cosmic rays of energy above the Greisen-Zatsepin-Kuzmin cutoff are exotic massive strongly interacting particles (uhecrons). We study the properties of air showers produced by uhecrons and find that…
Our Galaxy is the largest nuclear interaction experiment which we know, because of the interaction between cosmic ray particles and the interstellar material. Cosmic rays are particles, which have been accelerated in the Galaxy or in…
The origin and composition of ultra-high energy cosmic rays (UHECRs) remain a mystery. The common lore is that UHECRs are deflected from their primary directions by the Galactic and extragalactic magnetic fields. Here we describe an…
The spectrum of ultrahigh energy (above \approx 10^{9} GeV) cosmic rays is consistent with the decay of GUT scale particles. The predicted mass is m_X=10^b GeV, where b=14.6_{-1.7}^{+1.6}.
In this Letter we examine the arrival directions of the most energetic cosmic rays (E > 2 * 10^19 eV) detected by several air shower experiments. We find that data taken by different air shower arrays show positive correlations, indicating…
We review the hypothesis that the acceleration of protons at internal shocks in Gamma Ray Bursts (GRB) could be the origin of the ultra-high energy cosmic rays (UHECR) observed at earth, E_max > 10^19 eV. We find that, even though protons…
The energetics, spectrum, and composition of cosmic rays with energies below about $10^{15}$ eV are fairly well explained by models involving supernova shocks. In contrast, no widely accepted theory exists for the origin of ultra-high…
Extragalactic background of high energy neutrinos arising from the interactions of cosmic ray protons with far-infrared extragalactic background radiation is calculated. The main assumption is that the cosmic ray spectrum at energies higher…
It is argued that there are three `origins' of cosmic rays; the origin of the particles, the origin of the energy, and the site of the acceleration. The evidence for each origin is discussed and a plausible synthesis outlined for the…
In light of the mounting evidence that the highest energy cosmic rays are dominated by protons and not gamma-rays, we discuss the prospect that these cosmic rays are generated in the decay or annihilation of superheavy relic particles. We…
We study the large-scale distribution of the arrival directions of the highest energy cosmic rays observed by various experiments. Despite clearly insufficient statistics, we find a deficit of cosmic rays at energies higher than 10^{20} eV…
Ultra High Energy Cosmic Rays (UHECR) can be a signal from very early (post-inflationary) Universe. At this cosmological epoch Topological Defects (TD) and long-lived suprheavy (SH) particles are expected to be naturally and effectively…
Stable, quantized gravitational bound states of primordial black holes called Holeums could have been produced in the early universe and could be a component of the Super Heavy Dark Matter (SHDM) present in galactic halos. We show that…