The Minimal Type-I Seesaw Model and Flavor-dependent Leptogenesis

TL;DR

This paper explores a minimal type-I seesaw model with two nearly degenerate TeV-scale right-handed neutrinos, proposing a specific Yukawa texture that explains neutrino mixing and baryon asymmetry via flavor-dependent resonant leptogenesis.

Contribution

It introduces a novel neutrino Yukawa texture within the minimal seesaw framework that accounts for neutrino mixing patterns and baryon asymmetry through flavor-dependent leptogenesis mechanisms.

Findings

Predicts specific neutrino mixing angles and CP phase in different mass scenarios.

Shows that resonant leptogenesis can generate the observed baryon asymmetry.

Highlights the importance of flavor effects in leptogenesis calculations.

Abstract

In this talk, we first give a brief review of the so-called minimal seesaw models and then concentrate on the minimal type-I seesaw model with two almost degenerate right-handed Majorana neutrinos of ${\cal O}(1 {\rm TeV})$. A specific texture of the neutrino Yukawa coupling matrix is proposed to achieve the nearly tri-bimaximal neutrino mixing pattern. This ansatz predicts (1) $\theta^{}_{23} = \pi/4$, $|\delta| = \pi/2$ and $\sin^2 \theta^{}_{12} = (1 - 2 \tan^2 \theta^{}_{13})/3$ in the $m^{}_1 = 0$ case; and (2) $\theta^{}_{23} =\pi/4$ and $\theta^{}_{13} = \delta = 0$ in the $m^{}_3 = 0$ case. In both cases, the cosmological baryon number asymmetry can be explained via the resonant leptogenesis mechanism. Finally, we demonstrate the significance of flavor-dependent effects in our leptogenesis scenario.