Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On heavy Majorana neutrinos as a source of the highest energy cosmic
  rays   Cosmic ray events beyond the Greisen-Zatsepin-Kuzmin cut-off represent a
great challenge for particle physics and cosmology. We show that the physics of
heavy Majorana neutrinos, well defined by their masses, cross sections and
lifetimes, could explain the highest energy cosmic rays as a consequence of the
galactic annihilation of heavy neutrinos as cold dark matter particles.
Galactic nuclei accelerators, colliding neutron stars (black holes) or shocks
from the collapsed objects could produce ultra high energy cosmic rays as heavy
neutrinos beyond the mass threshold at an arbitrary cosmic distance. We comment
and also analyse the DAMA results with regard to heavy neutrinos as galactic
halo CDM particles.

14
The categories of this paper are: math-ph
34
The categories of this paper are: chem-ph
30
The categories of this paper are: q-alg
20
The categories of this paper are: acc-phys
22
The categories of this paper are: chao-dyn
32
The categories of this paper are: atom-ph
17
The categories of this paper are: q-fin
19
The categories of this paper are: eess
26
The categories of this paper are: bayes-an
25
The categories of this paper are: patt-sol
36
The categories of this paper are: cmp-lg
6
The categories of this paper are: astro-ph
13
The categories of this paper are: quant-ph
35
The categories of this paper are: mtrl-th
16
The categories of this paper are: stat
4
The categories of this paper are: cond-mat