Dark C P violation through the Z portal

Despite great agreement with experiment, the Standard Model (SM) of particle physics lacks a viable dark matter (DM) candidate and sufficient amount of C P violation to account for the observed baryon excess in the universe. Nonminimal Higgs frameworks are economic extensions of the SM which could remedy these shortcomings. Within the framework of a three Higgs doublet model, we introduce an extended dark sector which accommodates both DM and C P violation. Such dark sources of C P violation do not contribute to the electric dipole moments and are therefore unconstrained. We present a novel mechanism in which the C P -violating dark particles only interact with the SM through the gauge bosons, primarily the Z boson. Such Z -portal dark C P violation is realized in the regions of the parameter space where Higgs-mediated (co)annihilation processes are subdominant and have negligible contributions to the DM relic density. We show that such Z -portal C P -violating DM can still thermalize and satisfy all experimental and observational bounds and discuss the implications of such phenomena for electroweak baryogenesis. Figure Figure