Electromagnetic Leptogenesis

TL;DR

This paper proposes a novel leptogenesis mechanism where CP violation in electromagnetic dipole decays of heavy neutrinos generates the lepton asymmetry, offering an alternative to Yukawa-mediated processes.

Contribution

It introduces a new leptogenesis scenario based on electromagnetic dipole moments, with explicit calculations showing its viability and similar scale-mass relationships to standard models.

Findings

Lepton asymmetry can be generated via electromagnetic dipole decay interference.

The leptogenesis scale relates similarly to light neutrino masses as in standard mechanisms.

The proposed mechanism is consistent with existing neutrino mass constraints.

Abstract

We present a new leptogenesis scenario, where the lepton asymmetry is generated by CP violating decays of heavy electroweak singlet neutrinos via electromagnetic dipole moment couplings to the ordinary light neutrinos. Akin to the usual scenario where the decays are mediated through Yukawa interactions, we have shown, by explicit calculations, that the desired asymmetry can be produced through the interference of the corresponding tree-level and one-loop decay amplitudes involving the effective dipole moment operators. We also find that the relationship of the leptogenesis scale to the light neutrino masses is similar to that for the standard Yukawa-mediated mechanism.