Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Probing Grand Unified Theories with Cosmic Ray, Gamma-Ray and Neutrino
  Astrophysics   We explore scenarios where the highest energy cosmic rays are produced by new
particle physics near the grand unification scale. Using detailed numerical
simulations of extragalactic nucleon, gamma-ray, and neutrino propagation, we
show the existence of an interesting parameter range for which such scenarios
may explain part of the data and are consistent with all observational
constraints. A combination of proposed observatories for ultra-high energy
cosmic rays, neutrino telescopes of a few kilometer scale, and gamma-ray
astrophysics instruments should be able to test these scenarios. In particular,
for neutrino masses in the eV range, exclusive neutrino decay modes of
superheavy particles can give rise to neutrino fluxes comparable to those
predicted in models of active galactic nuclei.

24
The categories of this paper are: dg-ga
27
The categories of this paper are: comp-gas
10
The categories of this paper are: q-bio
33
The categories of this paper are: plasm-ph
35
The categories of this paper are: mtrl-th
7
The categories of this paper are: hep-th
12
The categories of this paper are: nucl-th
5
The categories of this paper are: gr-qc
28
The categories of this paper are: alg-geom
29
The categories of this paper are: funct-an
37
The categories of this paper are: supr-con
32
The categories of this paper are: atom-ph
15
The categories of this paper are: nucl-ex
31
The categories of this paper are: ao-sci
14
The categories of this paper are: math-ph
8
The categories of this paper are: hep-ex