We consider the possibility that ultra-high energy cosmic rays originate from the annihilation of relic superheavy darkmatter.We find that a cross section of 〈σAv〉 ∼ 10cm(MX/10 GeV)3/2 is required to account for the observed rate of super-GZK events if the superheavy dark matter follows a Navarro–Frenk–White density profile. This would require extremely large-l contributions to the annihilation...

Ultra high energy cosmic rays (UHECR) pose a problem either for particle physics or for astrophysics (or for both) by the unexpectedly high number of cosmic ray showers observed with energy above ≈ 5 × 10 19 eV , the Greisen-Zatsepin-Kuzmin (GZK) cutoff [1]. Our emphasis is on those possible solutions of the puzzle which assume that ultra high energy neutrinos travel cosmic distances. We presen...

In a recently proposed model the cosmic rays spectrum at energies above 10 eV can be fitted with a minimal number of unknown parameters assuming that the extragalactic cosmic rays are only protons with a power law source spectrum ∼ E and α ≃ 2.6 [1]. Within this minimal model, after fitting the observed HiRes spectrum with four parameters (proton injection spectrum power law index and maximum e...

An initial study of the extremely high energy (EHE) physics capability of the IceCube neutrino observatory is demonstrated by considering a GZK mechanism neutrino production model, which is a guaranteed source for EHE neutrinos. We study EHE event properties in the energy range 10 < E < 10 GeV observed by IceCube using detailed Monte Carlo simulation. Results of a simulation study show that abo...

The angular clustering of 5 Ultrahigh Energy Cosmic Rays (UHECRs) in the combined published AGASA-HiRes data has a probability of ∼ 2×10 of occurring by chance. A first analysis of the implications of the event energies and angular spreading is presented, which is applicable if the source is close enough that GZK losses can be ignored. Under this assumption, the observed energies of the events ...

Large scale airshower simulations around the GZK cutoff are performed. An extensive analysis of the behaviour of the various subcomponents of the cascade is presented. We focus our investigation both on the study of total and partial multiplicities along the entire atmosphere and on the geometrical structure of the various cascades, in particular on the lateral distributions. The possibility of...

It is difficult for conventional sources to accelerate cosmic ray particles to the highest energies that have been observed. Topological defects such as monopoles and strings overcome this difficulty, because their natural energy scale is at or above the observed energies. Monopoles connected by strings are a particularly attractive source, because they would cluster in the galactic halo and th...

On the analogy with the Lamb shift, we study the vacuum effect that proton’s electric field interacts with virtual particles in the vacuum. We find a possible quantum instability that triggered by an external force, proton’s electric field interacting with virtual particles spontaneously induces a quantum force that back reacts on the proton in the direction of the external trigger force. Such ...

The supersymmetric evolution of the fragmentation functions (or timelike evolution) within N = 1 QCD is discussed and predictions for the fragmentation functions of the theory (into final protons) are given. We use a backward running of the supersymmetric DGLAP equations, using a method developed in previous works. We start from the usual QCD parameterizations at low energy and run the DGLAP ba...