The electric dipole moment in a model for neutrino mass, dark matter and baryon asymmetry of the Universe

The electric dipole moment is examined in a three-loop neutrino mass model with dark matter originally proposed in Aoki et al. Phys. Rev. Lett. 102, 051805 (2009). The model contains a CP-violating phase in the Higgs potential which plays an important role in electroweak baryogenesis and is thus expected to explain the baryon asymmetry of the Universe simultaneously. However, such a CP-violating phase is severely constrained by the measurements of the electron electric dipole moment (eEDM), and a suppression mechanism for the eEDM is necessary to explain the observed baryon asymmetry while avoiding the constraint. In this paper, we examine neutrino mass, lepton-flavor-violating processes, dark matter, and the eEDM in the model. We show that the eEDM can be suppressed by destructive interference between the CP-violating phases in the Higgs sector and the dark sector with large CP-violating phases. We propose some benchmark scenarios including O (1) CP-violating phases where tiny neutrino mass and dark matter can be explained while avoiding all current experimental and theoretical constraints. These CP-violating phases are expected to be large enough to generate the observed baryon asymmetry in the electroweak baryogenesis scenario.