Darkogenesis: A baryon asymmetry from the dark matter sector

Abstract

In standard models of baryogenesis and of dark matter, the mechanisms which generate the densities in both sectors are unrelated to each other. In this paper we explore models which generate the baryon asymmetry through the dark matter sector, simultaneously relating the baryon asymmetry to the dark matter density. In the class of models we explore, a dark matter asymmetry is generated in the hidden sector through a first-order phase transition. Within the hidden sector, it is easy to achieve a sufficiently strong first-order phase transition and large enough CP violation to generate the observed asymmetry. This can happen above or below the electroweak phase transition, but in both cases significantly before the dark matter becomes nonrelativistic. We study examples where the asymmetric dark matter density is then transferred to the baryons both through perturbative and nonperturbative communication mechanisms, and show that in both cases cosmological constraints are satisfied while a sufficient baryon asymmetry can be generated.

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