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Seminar

Electric Dipole Moments of Charged Leptons with Sterile Fermions (in English)

  • SPEAKER: Dr. Takashi Toma (Laboratoire de Physique Theorique d'Orsay)
  • DATE: Oct/25 (Tue) 11:00
  • PLACE: Kenkyu Honkan 3F Meeting Room 322 

  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.