Leptogenesis from a $U(1)_D$ resonance

Abstract: We propose a novel mechanism to realize leptogenesis through the Breit-Wigner resonance of a dark $U(1)_D$ gauge boson $Z_D$, which mediates lepton number violating annihilations of dark matter (DM) in the context of the scotogenic model with a $U(1)_D$. The processes occur out of equilibrium and the DM freezes out lately giving rise to the observed abundance. The CP violation required for leptogenesis can be achieved by the interference between tree-level t-channel scattering of DM and the subsequent 1-loop mediated by $Z_D$, which arises due to the unremovable imaginary part of either the $Z_D$ propagator coming from its self-energy correction or the 1-loop giving rise to the effective coupling of $Z_D\bar{\nu}\nu$.