Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: X-ray Lines from Dark Matter: The Good, The Bad, and The Unlikely   We consider three classes of dark matter (DM) models to account for the
recently observed 3.5 keV line: metastable excited state DM, annihilating DM,
and decaying DM. We study two examples of metastable excited state DM. The
first, millicharged composite DM, has both inelasticity and photon emission
built in, but with a very constrained parameter space. In the second example,
up-scattering and decay come from separate sectors and is thus less
constrained. The decay of the excited state can potentially be detectable at
direct detection experiments. However we find that CMB constraints are at the
border of excluding this as an interpretation of the DAMA signal. The
annihilating DM interpretation of the X-ray line is found to be in tension with
CMB constraints. Lastly, a generalized version of decaying DM can account for
the data with a lifetime exceeding the age of the Universe for masses $\lesssim
10^{6}$ GeV.

18
The categories of this paper are: econ
17
The categories of this paper are: q-fin
29
The categories of this paper are: funct-an
37
The categories of this paper are: supr-con
2
The categories of this paper are: math
15
The categories of this paper are: nucl-ex
28
The categories of this paper are: alg-geom
33
The categories of this paper are: plasm-ph
9
The categories of this paper are: nlin
14
The categories of this paper are: math-ph
30
The categories of this paper are: q-alg
27
The categories of this paper are: comp-gas
11
The categories of this paper are: hep-lat
8
The categories of this paper are: hep-ex
32
The categories of this paper are: atom-ph
1
The categories of this paper are: cs