Gravitationally Induced Dark Matter Asymmetry and Dark Nucleon Decay

Abstract: The "gravitational baryogenesis" scenario is extended to generate both baryon and dark matter asymmetries, in the matter dominated era corresponding to post-inflationary reheating. A minimal extension requires a singlet fermion X for dark matter and a singlet scalar S. With two or more hidden sector fermions, the scenario can lead to nucleon decay into dark matter with a lifetime of order 10^{34-36} yr, which is relevant for current or future experiments. The correct multi-component relic density can be obtained if dark matter fermions couple to a sub-GeV vector boson that weakly interacts with the Standard Model through mixing. The typical inflationary scale in the scenario is of order 10^{16} GeV which suggests that tensor mode perturbations could potentially be within observational reach.