Ultra High Energy Cosmic Rays Spectra in Top-Down models
نویسندگان
چکیده
منابع مشابه
Ultra High Energy Cosmic Rays Spectra in Top-Down models
In this work we present a detailed computation of the spectra of UHECR in the top-down scenario. We compare the spectra of hadrons obtained by two different methods in QCD and supersymmetric (SUSY) QCD with large primary energies √ s up to 10 GeV. The two methods discussed are a Monte Carlo (MC) simulation and the evolution of the hadron fragmentation functions as described by the Dokshitzer-Gr...
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The origin of Ultra–High Energy (E ∼ 10 20 eV) Cosmic Rays (UHECR) remains mysterious. I discuss “top–down” models, where UHECR originate from the decay of very massive, long–lived particles. I summarize the calculation of the spectrum of decay products, discuss possible problems with this scenario, and describe ways to test it by searching for very energetic neutrinos and neutralinos. The obse...
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The current status of Ultra High Energy Cosmic Rays (UHECR) is reviewed, with emphasis given to theoretical interpretation of the observed events. The galactic and extragalactic origin, in case of astrophysical sources of UHE particles, have the problems either with acceleration to the observed energies or with the fluxes and spectra. Topological defects can naturally produce particles with ene...
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The origin of the particles in the highest energy end of the cosmic ray spectrum is discussed in the context of the wider problem of the origin of the whole cosmic radiation as observed at the Earth. In particular we focus our attention on the acceleration problem and on the transition from galactic to extragalactic cosmic rays.
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We discuss theoretical issues and experimental data that brought the ultra high energy cosmic rays in the list of Nature’s greatest puzzles. After many years of research we still do not know how astrophysical acceleration processes can reach energies exceeding 10 GeV. The main alternative top-down mechanism postulates the existence of super massive X-particles that create a particle spectrum ex...
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ژورنال
عنوان ژورنال: Nuclear Physics B - Proceedings Supplements
سال: 2004
ISSN: 0920-5632
DOI: 10.1016/j.nuclphysbps.2004.10.023