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
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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