Uniting low-scale leptogeneses

TL;DR

This paper unifies two previously distinct low-scale leptogenesis mechanisms, demonstrating they can generate the observed baryon asymmetry across a broad parameter space with experimentally accessible neutrino properties.

Contribution

It shows that leptogenesis via neutrino oscillations and resonant leptogenesis are actually unified mechanisms effective at right-handed neutrino masses above 100 MeV.

Findings

Baryon asymmetry can be generated for all allowed right-handed neutrino masses above 100 MeV.

Leptogenesis is effective with mass splitting up to 10% between neutrinos.

Large mixing angles between heavy and light neutrinos are compatible with successful leptogenesis.

Abstract

In this work we demonstrate that what was previously considered as different mechanisms of baryon asymmetry generation involving two right-handed Majorana neutrinos with masses far below the GUT scale -- leptogenesis via neutrino oscillations and resonant leptogenesis -- are actually united. We show that the observed baryon asymmetry can be generated for all experimentally allowed values of the right-handed neutrino masses above $M_N \gtrsim 100$ MeV. Leptogenesis is effective in a broad range of the parameters, including mass splitting between two right-handed neutrinos as big as $\Delta M_N/M_N \sim 0.1$, as well as mixing angles between the heavy and light neutrinos large enough to be accessible to planned intensity experiments or future colliders.