UV Freeze-in Leptogenesis via Dark Matter Oscillations

Models of freeze-in dark matter (DM) allow for the generation of the observed baryon asymmetry through the production, oscillation, and annihilation of DM particles. In contrast with earlier studies which have focused exclusively on IR-driven freeze-in of DM, we perform the first study of leptogenesis via UV freeze-in. We introduce two DM fermions and two scalars of different masses to consider two models of leptogenesis: in the mixed UV-IR model, DM freeze-in occurs via both decays of the lighter scalar and scattering of SM particles with a heavy virtual mediator; in the fully UV model, DM is produced only through scattering. Perturbatively solving the quantum kinetic equations, we find parameters consistent with the observed baryon asymmetry and DM abundance in both models; however, the fully UV scenario has a much narrower window of viable parameters. Our results afford points of comparison for understanding the different dynamics of IR and UV leptogenesis and point toward tests for their experimental verification.