Related papers: Ultra-high energy cosmic rays without GZK cutoff
Our Universe is described jointly by Einstein's relativity principle and the quantum principle; there the existence of the smallest units of matter, such as electrons, neutrinos, quarks, and photons, is well established and the smallest…
We consider the possibility that ultra-high energy cosmic rays originate from the annihilation of relic superheavy dark-matter particles. We find that a cross section of <sigma_A v> ~ 10^{-26}cm^2 (M_X/10^{12}GeV)^{3/2} is required to…
We propose a formula for flux of extremely high energy cosmic rays (EHECR) through decay of superheavy particles. It is shown that EHECR spectrum reported by AGASA is reproduced by the formula. The presence of EHECR suggests, according to…
We consider the advantages of and the problems associated with hypotheses to explain the origin of ulthrahigh energy cosmic rays (UHECR: E > 10 EeV) and the "trans GZK" cosmic rays (TGZK: E > 100 EeV), both through "old physics"…
The origin of ultrahigh-energy cosmic rays (UHECRs) is a half-century old enigma (Linsley 1963). The mystery has been deepened by an intriguing coincidence: over ten orders of magnitude in energy, the energy generation rates of UHECRs, PeV…
A model is proposed for the origin of cosmic rays (CRs) from ~10^14 eV to the highest energies, >10^20 eV. Gamma-Ray Bursts (GRBs) are assumed to inject CR protons and ions into the interstellar medium of star-forming galaxies--including…
We conjecture that the highest energy cosmic rays beyond the Greisen-Zatsepin-Kuzmin cut-off may provide a unique window into the very early epoch of the Universe, namely, that of reheating after inflation, provided these cosmic rays are…
Ultra-high energy cosmic rays (UHECRs) have been studied with the data of the Pierre Auger Observatory for more than fifteen years. An essential feature of the Observatory is its hybrid design: UHECRs are detected through the observation of…
We revisit constraints on decaying very heavy dark matter (VHDM) using the latest ultrahigh-energy cosmic-ray (UHECR; $E\gtrsim 10^{18}$ eV) data and ultrahigh-energy (UHE) $\gamma$-ray flux upper limits, measured by the Pierre Auger…
The decay of very heavy metastable relics of the Early Universe can produce ultra-high energy cosmic rays (UHECRs) in the halo of our own Galaxy. In this model, no Greisen-Zatsepin-Kuzmin cutoff is expected because of the short propagation…
We re-examine collisional annihilation of superheavy dark matter particles in dark matter density spikes in the galactic halo as a possible source of ultrahigh energy cosmic rays. We estimate the possible flux in a way that does not depend…
Ultra-high energy cosmic rays (UHECRs) are the highest energy messengers of the present universe, with energies up to $10^{20}$ eV. Studies of astrophysical particles (nuclei, electrons, neutrinos and photons) at their highest observed…
Understanding the origins of ultrahigh energy cosmic rays (UHECRs) - which reach energies in excess of $10^{20}~{\rm eV}$ - stretches particle acceleration physics to its very limits. In this review, we discuss how such energies can be…
We consider the recent results on UHECR (Ultra High Energy Cosmic Ray), clustering, composition, distribution in the sky, from the energy of several EeV with the dipole anisotropy up to the highest ones. We have suggested since 2008 and we…
It is pointed out that the observed extremely high energy cosmic rays (EHECR) above $10^{11}$ GeV and the observed baryon asymmetry of the Universe (BAU), both may have a common origin in baryon number violating decays of supermassive ``X''…
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…
In this thesis, I describe in great detail the physics of the decay of any Super-Heavy X particle (with masses up to the grand unification scale ~ 10^16 GeV and possibly beyond), and the computer code I developed to model this process -…
``Top--down'' models explain the observation of ultra high energy cosmic rays (UHECR; $E \gsim 5 \cdot 10^{19}$ eV) through the decay of very massive, long--lived ``$X$ particles''. If superparticles with masses near a TeV exist, $X$ decays…
A checklist of criteria is presented to help establish the sources of ultra-high energy cosmic rays (UHECRs). These criteria are applied to long-duration GRBs in order to determine if they are UHECR sources. The evidence seems to favor…
In a letter with the above title, published some time ago in PRL, Waxman made the interesting suggestion that cosmological gamma ray bursts (GRBs) are the source of the ultra high energy cosmic rays (UHECR). This has also been proposed…