Description
Authors: Peisi Huang, Tao Xu, Kairui Zhang
Presenter: Peisi Huang
Abstract: In this talk, I will discuss two new mechanisms for leptogenesis. In the first scenario, we introduce a temperature-dependent coupling between the right-handed neutrino and Standard Model parti- cles. This coupling experiences suppression at high temperatures and becomes sizable when the lepton asymmetry washout processes are Boltzmann-suppressed. Such a feature ensures that the washout rates remain consistently below the Hubble expansion rate, preserving all lepton asymme- try generated in the decay of right-handed neutrinos. In the second scenario, 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) N2 and N3 with a level of only ΔM32/M2∼(0.1%−1%). The lightest RHN, with a MeV-GeV mass, lies below the sphaleron freeze-out temperature and is stable, serving as a dark matter candidate. The model enables TeV- scale leptogenesis while avoiding the extreme mass degeneracy typically plagued conventional resonant leptogenesis. Baryon asymmetry, neutrino masses, and potentially dark matter relic den- sity can be addressed within a unified, experimentally testable framework.
