Baryon Asymmetry, Dark Matter and the Hidden Sector

Abstract

We propose a mechanism in which the baryon asymmetry of the Universe is produced in out-of-equilibrium, B — L and CP violating scattering processes that convert ordinary particles into particles of some hidden sector. The same mechanism should produce a non-zero asymmetry also in the hidden sector particles and thus the latter could provide a natural candidate for the dark matter. We discuss the example of the hidden mirror sector, which also provides a natural framework for the sterile neutrinos, and consider the processes lϕ → l′ϕ′, mediated by the heavy Majorana neutrinos N of the seesaw mechanism, where l and ϕ are ordinary lepton and Higgs doublets and l′, ϕ′ their hidden counterparts.