Asymmetric Dark Matter and Sommerfeld Enhancement

Abstract: We show that the relic density of asymmetric dark matter with long-range interactions is affected by the Sommerfeld enhancement. The annihilation cross section of asymmetric dark matter is enhanced due to the Sommerfeld effect. It results the relic density is decreased. Using the Planck date, the constraints on the asymmetry factor and coupling required to attain the observed dark matter density are obtained. We derive the upper bounds on the mass for asymmetric dark matter in s-wave and p-wave annihilation cases.