相关论文: Magnetic Monopoles as the Highest Energy Cosmic Ra…
We suggest that the highest energy $ \gsim 10^{20}$ eV cosmic ray primaries may be relativistic magnetic monopoles. Motivations for this hypothesis are twofold: (i) conventional primaries are problematic, while monopoles are naturally…
It is proposed that the highest energy $\sim 10^{20}$eV cosmic ray primaries are protons, decay products of a long-lived progenitor whose high kinetic energy arises from decay of a distant (cosmological) superheavy particle, G. Such a…
It is proposed that the highest energy $\sim 10^{20}$eV cosmic ray primaries are protons, decay products of a long-lived progenitor which has propagated from typically $\sim 100$Mpc. Such a scenario can occur in e.g. SU(15) grand…
Cosmic rays with energies exceeding $10^{20}\eV$ have been detected. The origin of these highest energy cosmic rays remains unknown. Established astrophysical acceleration mechanisms encounter severe difficulties in accelerating particles…
In this article we examine the question of whether the highest energy cosmic ray primaries could be ultra relativistic magnetic monopoles. The analysis is performed within the framework of large compact dimensions and TeV scale quantum…
We argue that magnetic monopoles can not be associated to the highest energy cosmic rays as recently suggested. Both the observed spectrum and the arrival direction disagree with observation.
Ultra-high energy (UHE) photons above 10^{18} eV serve as valuable probes of fundamental physics. While typically produced in interactions involving charged particles, they could also originate from exotic sources such as annihilations of…
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 $\Delta$…
Ultra high energy cosmic rays have been see coming from the direction of the local cosmic void. We use this fact to argue that at least some of these these cosmic rays are relatively light magnetic monopoles and that their relative fraction…
It is commonly accepted that high energy cosmic rays up to $10^{19}$ eV can be produced in catastrophic astrophysical processes. However the source of a few observed events with higher energies remains mysterious. We propose that they may…
The electromagnetic decay and final annihilation of magnetic monopole-antimonopole pairs formed in the early universe has been proposed as a possible mechanism to produce the highest energy cosmic rays. We show that for a monopole abundance…
This talk explores the possibility that the Universe may be populated with relic magnetic monopoles. Observations of galactic and extragalactic magnetic fields, lead to the conclusion that monopoles of mass < 10^{14} GeV are accelerated in…
We give a summary of the theoretical attempts to make sense of the observational data concerning the highest energy cosmic rays, (E > 3x10^{19} eV).
The observation of twenty cosmic-ray air-showers at and above 10^{20} eV poses fascinating problems for particle astrophysics: how the primary particles are accelerated to these energies, how the primaries get here through the 2.7K…
The existence of cosmic rays of energies exceeding 10^20 eV is one of the mysteries of high energy astrophysics. The spectrum and the high energy to which it extends rule out almost all suggested source models. The challenges posed by…
The detection of cosmic rays with energy around and in excess of $10^{20}$ eV raises many questions that future experiments will help answering to. I address here my view of some of these open issues, as they are now and as they might be…
Considerations of the collision losses for protons traversing the 2.7 K black body microwave radiation field have led to the conclusion that the highest energy cosmic rays, those observed at $\geq 10^{20}$ eV, must come from sources within…
Recent measurements of the properties of cosmic rays above 10^17 eV are summarized and implications on our contemporary understanding of their origin are discussed. Cosmic rays with energies exceeding 10^20 eV have been measured, they are…
A sufficiently magnetized Local Supercluster can explain the spectrum and angular distribution of ultra-high energy cosmic rays. We show that the spectrum of extragalactic cosmic rays with energies below $\sim 10^{20}$ eV may be due to the…
The origin of cosmic ray events with $E \gsim 10^{11}$ GeV remains mysterious. In this talk I briefly summarize several proposed particle physics explanations: a breakdown of Lorentz invariance, the ``$Z-$burst'' scenario, new hadrons with…