Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Strongly-interacting massive particle and dark photon in the era of
  intensity frontier   A strongly interacting massive particle (SIMP) is an interesting candidate
for dark matter (DM) because its self-interaction cross section can be
naturally strong enough to address the astrophysical problem of small-scale
structure formation. A simple model was proposed by assuming a monopole
condensation, where composite SIMP comes from a "strongly interacting"
U(1)$_{\rm d}$ gauge theory. In the original model, the DM relic abundance is
determined by the $3\to2$ annihilation process via the Wess-Zumino-Witten term.
In this letter, we discuss that the DM relic abundance is naturally determined
also by a semi-annihilation process via a kinetic mixing between the
hypercharge gauge boson and the dark U(1)$_{\rm d}$ gauge boson (dark photon).
The dark photon can be discovered by LDMX-style missing momentum experiments in
the near future.

7
The categories of this paper are: hep-th
13
The categories of this paper are: quant-ph
8
The categories of this paper are: hep-ex
35
The categories of this paper are: mtrl-th
1
The categories of this paper are: cs
11
The categories of this paper are: hep-lat
23
The categories of this paper are: solv-int
36
The categories of this paper are: cmp-lg
30
The categories of this paper are: q-alg
14
The categories of this paper are: math-ph
34
The categories of this paper are: chem-ph
32
The categories of this paper are: atom-ph
20
The categories of this paper are: acc-phys
21
The categories of this paper are: adap-org
25
The categories of this paper are: patt-sol
4
The categories of this paper are: cond-mat