Flavoured Resonant Leptogenesis at Sub-TeV Scales

TL;DR

This paper explores flavoured resonant leptogenesis at sub-TeV scales within a minimal type-I seesaw model, demonstrating that successful baryon asymmetry generation is possible for neutrino masses between 0.3 and 100 GeV, with flavour effects significantly enhancing the asymmetry.

Contribution

It provides a detailed analysis of flavoured leptogenesis at low scales, highlighting the importance of flavour effects and identifying the mass range where successful leptogenesis can occur.

Findings

Successful leptogenesis for neutrino masses 0.3-100 GeV.

Flavour effects can enhance baryon asymmetry by up to 300 times.

Leptogenesis can occur even with vanishing initial right-handed neutrino abundance.

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.