Rescuing leptogenesis in inverse seesaw models with the help of non-Abelian flavor symmetries

Abstract

The inverse seesaw (ISS) model provides an attractive framework that can naturally explain the smallness of neutrino masses while accommodating some sterile neutrinos potentially accessible at present or future experiments. However, in generic ISS models with hierarchical pseudo-Dirac (PD) sterile neutrino pairs, the generation of the observed baryon asymmetry of the Universe via the leptogenesis mechanism is extremely challenging. In this paper, we investigate rescuing leptogenesis in the ISS model with the help of non-Abelian flavor symmetries which have the potential to explain the observed peculiar neutrino mixing pattern: we first implement non-Abelian flavor symmetries to naturally enforce mass degeneracies among different pseudo-Dirac sterile neutrino pairs and then break them in a proper way so that resonant leptogenesis among different PD sterile neutrino pairs can arise, thus enhancing the generated baryon asymmetry. To be specific, we have considered the following two well-motivated approaches for generating the tiny mass splittings among different PD sterile neutrino pairs: one approach makes use of the renormalization-group corrections to the sterile neutrino masses, while the other approach invokes non-trivial flavor structure of the $\mu_{\rm s}$ matrix. For these two scenarios, we aim to explore the viability of leptogenesis and to identify the conditions under which the observed baryon asymmetry can be successfully reproduced.