Neutrino magnetic moments and electromagnetic leptogenesis

Abstract

We analyze the connection between neutrino magnetic moments and neutrino masses. Electroweak radiative corrections to the neutrino mass are used to derive naturalness upper bounds on neutrino magnetic moments, generated by physics above the electroweak scale. For Dirac (Majorana) neutrinos the bound is several orders of magnitude stronger (weaker) than present experimental limits. The discovery of a neutrino magnetic moment near the present experimental sensitivity would thus suggest that neutrinos are Majorana particles. We also outline a new baryogenesis-vialeptogenesis scenario where the lepton asymmetry is generated by CP violating decays of heavy right handed neutrinos via electromagnet..