Electron electric dipole moment in Inverse Seesaw models

TL;DR

This paper investigates how sterile neutrinos in the Inverse Seesaw model can significantly contribute to the electron's electric dipole moment, potentially detectable in future experiments, and explores leptogenesis compatibility.

Contribution

It provides a minimal realisation of the Inverse Seesaw model showing substantial contributions to the electron EDM from heavy pseudo-Dirac neutrinos, linking neutrino physics with CP violation.

Findings

Heavy pseudo-Dirac neutrinos can induce electron EDM near experimental sensitivity

Two-loop diagrams dominate the EDM contribution

Leptogenesis can be compatible with large electron EDM in this framework

Abstract

We consider the contribution of sterile neutrinos to the electric dipole moment of charged leptons in 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 if their masses are above the electroweak scale. The major contribution comes from two-loop diagrams with pseudo-Dirac neutrino states running in the loops. In our analysis we further discuss the possibility of having a successful leptogenesis in this framework, compatible with a large electron electric dipole moment.