Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Cosmological constraints on dark matter models with velocity-dependent
  annihilation cross section   We derive cosmological constraints on the annihilation cross section of dark
matter with velocity-dependent structure, motivated by annihilating dark matter
models through Sommerfeld or Breit-Wigner enhancement mechanisms. In models
with annihilation cross section increasing with decreasing dark matter
velocity, big-bang nucleosynthesis and cosmic microwave background give
stringent constraints.

7
The categories of this paper are: hep-th
13
The categories of this paper are: quant-ph
36
The categories of this paper are: cmp-lg
29
The categories of this paper are: funct-an
35
The categories of this paper are: mtrl-th
9
The categories of this paper are: nlin
17
The categories of this paper are: q-fin
14
The categories of this paper are: math-ph
32
The categories of this paper are: atom-ph
20
The categories of this paper are: acc-phys
26
The categories of this paper are: bayes-an
16
The categories of this paper are: stat
27
The categories of this paper are: comp-gas
10
The categories of this paper are: q-bio
37
The categories of this paper are: supr-con
24
The categories of this paper are: dg-ga