Flavoured Resonant Leptogenesis at Sub-TeV Scales

Abstract

We consider sub-TeV scale flavoured resonant leptogenesis within the minimal type-I seesaw scenario with two right-handed singlet neutrinos $N_{1,2}$ forming a pseudo-Dirac pair, concentrating on the case of masses of the pseudo-Dirac pair having values $M_{1,2} \lesssim 100$ GeV. The case when the CP violating asymmetries in the individual lepton charges $L_l$, $l=e,\mu,\tau$, and in the total lepton charge $L$ of the Universe are generated in $1 \leftrightarrow 2$ decay processes is investigated. We show that successful leptogenesis is possible for $M_{1,2}$ lying in the interval $M_{1,2} = (0.3 - 100)$ GeV. Our results show also, in particular, that for vanishing initial $N_{1,2}$ abundance, flavour effects can play an important role in the generation of the baryon asymmetry, leading to an enhancement of the asymmetry by a factor up to $\sim 300$ with respect to the "unflavoured" leptogenesis scenario.