Abstract
The relic abundance of particle and antiparticle dark matter (DM) need not be vastly different in thermal asymmetric dark matter (ADM) models. By considering the effect of a primordial asymmetry on the thermal Boltzmann evolution of coupled DM and anti-DM, we derive the requisite annihilation cross section. This is used in conjunction with cosmic microwave background and Fermi-LAT gamma-ray data to impose a limit on the number density of anti-DM particles surviving thermal freeze-out. When the extended gamma-ray emission from the Galactic Center is reanalyzed in a thermal ADM framework, we find that annihilation into leptons prefer anti-DM number densities 1%–4% that of DM while the -quark channel prefers 50%–100%.
- Received 2 September 2014
DOI:https://doi.org/10.1103/PhysRevD.91.023505
© 2015 American Physical Society