Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Additional bounds on the pre Big--Bang--Nucleosynthesis Expansion by
  means of $\gamma$-rays from the Galactic Center   The possibility to use $\gamma$--ray data from the Galactic Center (GC) to
constrain the cosmological evolution of the Universe in a phase prior to
primordial nucleosyntesis, namely around the time of cold dark matter (CDM)
decoupling, is analyzed. The basic idea is that in a modified cosmological
scenario, where the Hubble expansion rate is enhanced with respect to the
standard case, the CDM decoupling is anticipated and the relic abundance of a
given dark matter (DM) candidate enhanced. This implies that the present amount
of CDM in the Universe may be explained by a Weakly Interacting Massive
Particle (WIMP) which possesses annihilation cross section (much) larger than
in standard cosmology. This enhanced annihilation implies larger fluxes of
indirect detection signals of CDM. We show that the HESS measurements can set
bounds for WIMPs heavier than a few hundreds of GeV, depending on the actual DM
halo profile. These results are complementary to those obtained in a previous
analysis based on cosmic antiprotons. For a Moore DM profile, $\gamma$--ray
data limit the maximal Hubble rate enhancement to be below a factor of 100.
Moreover, a WIMP heavier than 1 TeV is not compatible with a cosmological
scenario with enhanced expansion rate prior to Big Bang Nucleosynthesis (BBN).
Less steep DM profiles provide less stringent bounds, depending of the
cosmological scenario.

2
The categories of this paper are: math
27
The categories of this paper are: comp-gas
24
The categories of this paper are: dg-ga
32
The categories of this paper are: atom-ph
18
The categories of this paper are: econ
33
The categories of this paper are: plasm-ph
22
The categories of this paper are: chao-dyn
14
The categories of this paper are: math-ph
35
The categories of this paper are: mtrl-th
11
The categories of this paper are: hep-lat
13
The categories of this paper are: quant-ph
10
The categories of this paper are: q-bio
16
The categories of this paper are: stat
17
The categories of this paper are: q-fin
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The categories of this paper are: hep-ex
36
The categories of this paper are: cmp-lg