Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Anapole dark matter annihilation into photons   In models of anapole dark matter (DM), the DM candidate is a Majorana fermion
whose primary interaction with standard model (SM) particles is through an
anapole coupling to off-shell photons. As such, at tree-level, anapole DM
undergoes p-wave annihilation into SM charged fermions via a virtual photon.
But, generally, Majorana fermions are polarizable, coupling to two real
photons. This fact admits the possibility that anapole DM can annihilate into
two photons in an s-wave process. Using an explicit model, we compute both the
tree-level and diphoton contributions to the anapole DM annihilation cross
section. Depending on model parameters, the s-wave process can either rival or
be dwarfed by the p-wave contribution to the total annihilation cross section.
Subjecting the model to astrophysical upper bounds on the s-wave annihilation
mode, we rule out the model with large s-wave annihilation.

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The categories of this paper are: patt-sol
16
The categories of this paper are: stat
18
The categories of this paper are: econ
3
The categories of this paper are: physics
31
The categories of this paper are: ao-sci
10
The categories of this paper are: q-bio
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The categories of this paper are: bayes-an
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The categories of this paper are: plasm-ph
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The categories of this paper are: adap-org
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The categories of this paper are: quant-ph
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The categories of this paper are: chem-ph
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The categories of this paper are: supr-con
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The categories of this paper are: q-alg
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The categories of this paper are: chao-dyn
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The categories of this paper are: hep-ex
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The categories of this paper are: alg-geom