Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Sommerfeld enhancement for scalar particles and application to
  sfermion co-annihilation regions   We study the impact of the Sommerfeld enhancement on the thermal relic
density of the lightest neutralino in the case of large co-annihilation effects
with a scalar particle. The proper way of including the Sommerfeld effect in
this case is discussed, and the appropriate formulas for a general scenario
with a set of particles with arbitrary masses and (off-)diagonal interactions
are provided. We implement these results to compute the relic density in the
neutralino sfermion co-annihilation regions in the mSUGRA framework. We find
non-negligible effects in whole sfermion co-annihilation regimes. For stau
co-annihilations the correction to the relic density is of the order of several
per cent, while for stop co-annihilations is much larger, reaching a factor of
5 in some regions of the parameter space. A numerical package for computing the
neutralino relic density including the Sommerfeld effect in a general MSSM
setup is made public available.

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The categories of this paper are: alg-geom
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The categories of this paper are: acc-phys
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The categories of this paper are: math
3
The categories of this paper are: physics
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The categories of this paper are: chem-ph
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The categories of this paper are: mtrl-th
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The categories of this paper are: funct-an
4
The categories of this paper are: cond-mat
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The categories of this paper are: nucl-ex
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The categories of this paper are: chao-dyn
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The categories of this paper are: nucl-th
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The categories of this paper are: supr-con
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The categories of this paper are: ao-sci
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The categories of this paper are: gr-qc
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The categories of this paper are: q-fin
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The categories of this paper are: comp-gas