Speaker
Description
In this talk I will start by considering a question which curiously had not been properly considered so far: in the standard seesaw model what is the minimum value the mass of a right-handed (RH) neutrino must have for allowing successful leptogenesis via CP-violating decays? I show that, for low RH neutrino masses and thanks to thermal effects, leptogenesis turns out to proceed efficiently from the decay of the Standard Model scalar doublet components into a RH neutrino and a lepton. If the RH neutrino has thermalized prior from producing the asymmetry, this mechanism turns out to lead to the bound mN>2 GeV. If, instead, the RH neutrinos have not thermalized, leptogenesis from these decays is enhanced further and can be easily successful, even at lower scales. This Higgs-decay leptogenesis new mechanism works without requiring an interplay of flavor effects and/or cancellations of large Yukawa couplings in the neutrino mass matrix. Last but not least, such a scenario turns out to be testable, from direct production of the RH neutrino(s).
