Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Diffuse MeV Gamma-rays and Galactic 511 keV Line from Decaying WIMP Dark
  Matter   The origin of both the diffuse high-latitude MeV gamma-ray emission and the
511 keV line flux from the Galactic bulge are uncertain. Previous studies have
invoked dark matter physics to independently explain these observations, though
as yet none has been able to explain both of these emissions within the
well-motivated framework of Weakly-Interacting Massive Particles (WIMPs). Here
we use an unstable WIMP dark matter model to show that it is in fact possible
to simultaneously reconcile both of these observations, and in the process show
a remarkable coincidence: decaying dark matter with MeV mass splittings can
explain both observations if positrons and photons are produced with similar
branching fractions. We illustrate this idea with an unstable branon, which is
a standard WIMP dark matter candidate appearing in brane world models with
large extra dimensions. We show that because branons decay via three-body final
states, they are additionally unconstrained by searches for Galactic MeV
gamma-ray lines. As a result, such unstable long-lifetime dark matter particles
provide novel and distinct signatures that can be tested by future observations
of MeV gamma-rays.

32
The categories of this paper are: atom-ph
5
The categories of this paper are: gr-qc
2
The categories of this paper are: math
23
The categories of this paper are: solv-int
11
The categories of this paper are: hep-lat
14
The categories of this paper are: math-ph
1
The categories of this paper are: cs
27
The categories of this paper are: comp-gas
29
The categories of this paper are: funct-an
37
The categories of this paper are: supr-con
24
The categories of this paper are: dg-ga
28
The categories of this paper are: alg-geom
16
The categories of this paper are: stat
9
The categories of this paper are: nlin
34
The categories of this paper are: chem-ph
7
The categories of this paper are: hep-th