Leptogenesis, dark matter and gravitational waves from discrete symmetry breaking

We analyse a model that connects the neutrino sector and the dark sector of the universe via a mediator Φ, stabilised by a discrete 𝒵 4 symmetry that breaks to a remnant 𝒵 2 upon Φ acquiring a non-zero vacuum expectation value ( v ϕ ). The model accounts for the observed baryon asymmetry of the universe via additional contributions to the canonical Type-I leptogenesis. The 𝒵 4 symmetry breaking scale ( v ϕ ) in the model not only establishes a connection between the neutrino sector and the dark sector, but could also lead to gravitational wave signals that are within the reach of current and future experimental sensitivities.