Dark Matter, Shared Asymmetries, and Galactic Gamma Ray Signals

Understand

We introduce a novel dark matter scenario where the visible sector and the dark sector share a common asymmetry.

• The two sectors are connected through an unstable mediator with baryon number one, allowing the standard model baryon asymmetry to be shared with dark matter via semi-annihilation.
• The present-day abundance of dark matter is then set by thermal freeze-out of this semi-annihilation process, yielding an asymmetric version of the WIMP miracle as well as promising signals for indirect detection experiments.
• As a proof of concept, we find a viable region of parameter space consistent with the observed Fermi excess of GeV gamma rays from the galactic center.