Speaker
Description
In this talk, we will present a possibility of realising successful cogenesis of baryon asymmetry of the Universe, dark matter and neutrino masses within the minimal scotogenic model with low-mass right handed neutrinos (RHN). In the conventional thermal scotogenic leptogenesis setup, there exists a viable parameter space with smaller masses for RHNs as compared to Type-I seesaw case, because the Yukawa couplings for RHNs can be stronger for the same neutrino masses. However, the thermal leptogenesis in the minimal case with two hierarchical RHNs is limited due to the interplay between CP asymmetry generation and washout effects, which typically leads to relatively heavy RHNs. We will show that the presence of a time-dependent Majoron background originating from a global symmetry breaking through its associated Majoron velocity, provides an effective chemical potential that significantly alters the leptogenesis dynamics. This mechanism revives a previously inaccessible low-mass RHN regime while remaining consistent with radiative neutrino mass generation and weakly interacting dark matter. We will discuss the parameter space that successfully reproduces both the observed baryon asymmetry of the Universe and the dark matter relic abundance, highlighting the prospects for low-scale leptogenesis in the minimal scotogenic framework.