Similar dark matter and baryon abundances with TeV-scale leptogenesis

Abstract

We estimate the Baryon Asymmetry of the Universe (BAU) produced in an inverse seesaw model containing extra light singlets, and with lepton number conservation prior to the electroweak phase transition. A CP asymmetry ε ∼ O(1) is required to obtain a large enough BAU. We discuss the relation between the baryon and WIMP relic densities in baryogenesis scenarios using the out-of-equilibrium decay of a baryon-parent of mass M : when baryon number violation freezes out, the remaining density of baryon-parents is ∼ M/m W× the WIMP relic density. So the baryon/WIMP ratio is ∼ εM/m W. A natural explanation of the similar WIMP and baryon densities could be that CP violation is of order the ratio m W/M.