https://doi.org/10.1140/epjc/s10052-018-5555-0
Regular Article - Theoretical Physics
Explanation of the 511 keV line: cascade annihilating dark matter with the 
Be anomaly
School of Science, Southwest University of Science and Technology, Mianyang, 621010, China
* e-mail: jialb@mail.nankai.edu.cn
Received:
22
October
2017
Accepted:
13
January
2018
Published online:
7
February
2018
A possible dark matter (DM) explanation about the long-standing issue of the Galactic 511 keV line is explored in this paper. For DM cascade annihilations of concern, a DM pair 
annihilates into unstable 
, and 
decays into 
with new interactions suggested by the Be anomaly. Considering the constraints from the effective neutrino number 
and the 511 keV gamma-ray emission, a range of DM is obtained, 
MeV. The typical DM annihilation cross section today is about 3.3 
cm
s
, which can give an explanation about the 511 keV line. The MeV scale DM may be searched by the DM-electron scattering, and the upper limit set by the CMB s-wave annihilation is derived in DM direct detections.
© The Author(s), 2018
