Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Monochromatic Gamma Rays from Dark Matter Annihilation to Leptons   We investigate the relation between the annihilation of dark matter (DM)
particles into lepton pairs and into 2-body final states including one or two
photons. We parametrize the DM interactions with leptons in terms of contact
interactions, and calculate the loop-level annihilation into monochromatic
gamma rays, specifically computing the ratio of the DM annihilation cross
sections into two gamma rays versus lepton pairs. While the loop-level
processes are generically suppressed in comparison with the tree-level
annihilation into leptons, we find that some choices for the mediator spin and
coupling structure lead to large branching fractions into gamma-ray lines. This
result has implications for a dark matter contribution to the AMS-02 positron
excess. We also explore the possibility of mediators which are charged under a
dark symmetry and find that, for these loop-level processes, an effective field
theory description is accurate for DM masses up to about half the mediator
mass.

21
The categories of this paper are: adap-org
24
The categories of this paper are: dg-ga
19
The categories of this paper are: eess
7
The categories of this paper are: hep-th
34
The categories of this paper are: chem-ph
32
The categories of this paper are: atom-ph
18
The categories of this paper are: econ
14
The categories of this paper are: math-ph
23
The categories of this paper are: solv-int
22
The categories of this paper are: chao-dyn
2
The categories of this paper are: math
9
The categories of this paper are: nlin
4
The categories of this paper are: cond-mat
36
The categories of this paper are: cmp-lg
1
The categories of this paper are: cs
33
The categories of this paper are: plasm-ph