Speaker
Hidenaga Watanabe
Description
In standard leptogenesis, several conditions must be satisfied to produce the observed baryon asymmetry: weak wash-out, CP violation in the neutrino Yukawa couplings, and a heavy Majorana mass.
We propose a new mechanism for leptogenesis that relaxes these conditions by employing three-Higgs-doublet models. The non-thermal decay of an additional heavy Higgs generates a charge asymmetry, which remains conserved in the early universe. This asymmetry is subsequently converted into a lepton asymmetry through thermal processes involving neutrino Yukawa interactions.
Our results indicate that the Majorana mass scale can be reduced to as low as 10^5GeV.
