Phase Separation Unlocks Resonant Leptogenesis

Abstract

Distinct behavior of decaying particles in true and false vacua of the theory can lead to enhanced generation of baryon asymmetry, a scenario we call \textit{phase separation baryogenesis}. We demonstrate that for leptogenesis this naturally allows for right handed neutrinos to generate resonantly-enhanced lepton asymmetry without fine-tuning of their masses as in typical theories. Our mechanism allows for a variety of neutrino mass hierarchies and hence possible novel connections with observations. We present a concrete realization in a minimal model with a scalar field undergoing a phase transition.