Xiang-Yi Wu | Searcharxiv

arXiv2024

A complete study of RGE induced leptogenesis in flavor symmetry scenarios

In the literature, motivated by the observed peculiar neutrino mixing pattern and a preliminary experimental hint for maximal Dirac CP phase (i.e., $δ\sim 3π/2$), a lot of flavor and CP symmetries have been proposed to help us understand and explain these experimental results. However, for some flavor-symmetry scenarios (see section~3.1), the leptogenesis mechanism is prohibited to work as usual. To tackle this problem, in this paper we have made an exhausitive study on the possibility that the renormalization group evolution effect may induce a successful leptogenesis for these particular scenarios. Our study provides some complementarities to the previous related studies in Refs. [26, 27, 28] (see section~3.2).

hep-ph↗

arXiv2024

Purely flavored leptogenesis from a sudden mass gain of right-handed neutrinos

In this paper, we would like to point out that in the scenario that the right-handed neutrinos suddenly gain some masses much larger than the temperature of the Universe at that time so that the washout effects for the lepton asymmetry generated from their decays can be neglected safely, the purely flavored leptogenesis scenario (in which the total CP asymmetries for the decays of the right-handed neutrinos are vanishing and the successful leptogenesis is realized by virtue of the flavor non-universality of the washout effects) cannot work in the usual way any more. For this problem, we put forward that the flavor non-universality of the conversion efficiencies from the flavored lepton asymmetries to the baryon asymmetry via the sphaleron processes may play a crucial role. And we will study if the requisite baryon asymmetry can be successfully reproduced from such a mechanism in the scenarios that the right-handed neutrino masses are hierarchical and nearly degenerate, respectively. A detailed study shows that this mechanism can be viable in both these two scenarios.

hep-ph↗