Testable Flavored TeV-scale Resonant Leptogenesis with MeV-GeV Dark Matter in a Neutrinophilic 2HDM

Abstract

We explore flavored resonant leptogenesis embedded in a neutrinophilic 2HDM. Successful leptogenesis is achieved by the very mildly degenerate two heavier right-handed neutrinos (RHNs), $N_2$ and $N_3$, with mass splitting of only $\Delta M_{32}/M_2 \sim \mathcal{O}(0.1\%-1\%)$. The lightest RHN, with MeV-GeV-scale mass, lies below the sphaleron freeze-out temperature and remains stable, serving as a dark matter candidate. The model enables TeV-scale leptogenesis while avoiding the extreme mass degeneracy plagued conventional resonant leptogenesis. Baryon asymmetry, neutrino masses, and potentially the dark matter relic density can be addressed within a unified and experimentally testable framework.