Electric Dipole Moments of Charged Leptons with Sterile Fermions
SPEAKER
Takashi Toma, Laboratoire de Physique Theorique d'Orsay
PLACE
Seminar room, Kenkyu honkan 3F
We address the impact of sterile fermions on charged lepton electric dipole moments. In this work, we consider a minimal extension of the Standard Model via the addition of sterile fermions which mix with active neutrinos. Our study reveals that, in order to have a non-vanishing contribution in this framework, the minimal extension necessitates the addition of at least 2 sterile fermion states. Sterile neutrinos can give significant contributions to the charged lepton electric dipole moments if the masses of the non-degenerate sterile states are both above the electroweak scale. In addition, the Majorana nature of neutrinos is also important for the charged lepton electric dipole moments. Furthermore as a more concrete model, we consider the most minimal realisation of the Inverse Seesaw mechanism, in which the Standard Model is extended by two right-handed neutrinos and two sterile fermion states. Our study shows that the two pairs of (heavy) pseudo-Dirac mass eigenstates can give significant contributions to the electron electric dipole moment, lying close to future experimental sensitivity. In our analysis we further discuss the possibility of having a successful leptogenesis in this framework, compatible with a large electron electric dipole moment.