Sommerfeld Enhancements for Asymmetric Dark Matter

Abstract

We extend the analysis of asymmetric Dark Matter relic density with Sommerfeld enhancement to the case where the mediator is massive. In asymmetric Dark Matter models, the asymmetric Dark Matter is assumed to couple to light scalar or vector boson. Asymmetric Dark Matter annihilation cross section is enhanced by the Sommerfeld effect which exists due to the distortion of wavefunction of asymmetric Dark Matter particle and anti--particle by long--range interactions. The impacts of Sommerfeld enhancement on the relic densities of asymmetric Dark Matter particle and anti--particle are discussed. The effect of kinetic decoupling on the relic density is also probed when the annihilation cross section is enhanced by Sommerfeld enhancement. Finally, the constraints on the parameter space is given by using the observational data of Dark Matter.