Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Early-Universe Constraints on Dark Matter-Baryon Scattering and their
  Implications for a Global 21cm Signal   We present and compare several cosmological constraints on the cross section
for elastic scattering between dark matter (DM) and baryons, for cross sections
with a range of power-law dependences on the DM-baryon relative velocity $v$,
especially focusing on the case of $\sigma \propto v^{-4}$. We study
constraints spanning a wide range of epochs in cosmological history, from
pre-recombination distortions to the blackbody spectrum and anisotropies of the
cosmic microwave background (CMB), to modifications to the intergalactic medium
temperature and the resulting 21cm signal, and discuss the allowed signals in
the latter channels given the constraints from the former. We improve previous
constraints on DM-baryon scattering from the CMB anisotropies, demonstrate via
principal component analysis that the effect on the CMB can be written as a
simple function of DM mass, and map out the redshifts dominating this signal.
We show that given high-redshift constraints on DM-baryon scattering, a
$v^{-4}$ scaling of the cross section for light DM would be sufficient to
explain the deep 21cm absorption trough recently claimed by the EDGES
experiment, if 100% of the DM scatters with baryons. For millicharged DM models
proposed to explain the observation, where only a small fraction of the DM
interacts, we estimate that a PIXIE-like future experiment measuring CMB
spectral distortion could test the relevant parameter space.

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The categories of this paper are: eess
1
The categories of this paper are: cs
7
The categories of this paper are: hep-th
16
The categories of this paper are: stat
24
The categories of this paper are: dg-ga
25
The categories of this paper are: patt-sol
37
The categories of this paper are: supr-con
31
The categories of this paper are: ao-sci
29
The categories of this paper are: funct-an
4
The categories of this paper are: cond-mat
18
The categories of this paper are: econ
27
The categories of this paper are: comp-gas
34
The categories of this paper are: chem-ph
23
The categories of this paper are: solv-int
22
The categories of this paper are: chao-dyn
10
The categories of this paper are: q-bio