Minimal Textures in Seesaw Mass Matrices and their low and high Energy Phenomenology

TL;DR

This paper explores minimal textures in Dirac and Majorana mass matrices within the type I seesaw mechanism, analyzing their phenomenological implications for neutrino physics, leptogenesis, and lepton flavor violation.

Contribution

It identifies the most minimal texture zero configurations in Dirac and Majorana mass matrices compatible with low energy phenomenology and discusses their implications for high-energy processes.

Findings

Five-zero Dirac textures can successfully reproduce low energy data.

Degenerate eigenvalues arise in minimal non-diagonal textures.

Certain textures have significant implications for leptogenesis and lepton flavor violation.

Abstract

In an attempt to find minimal scenarios we study the implications of Dirac and Majorana mass matrices with texture zeros within the type I seesaw mechanism. For the Dirac mass matrices we consider 5 zero textures which we show to be the most minimal form that can successfully account for low energy phenomenology if the Majorana mass matrices are chosen minimal as well. For those, we consider both diagonal and even more minimal non-diagonal forms. The latter can be motivated e.g. by simple U(1) flavour symmetries and have two degenerate eigenvalues. We classify the allowed textures and discuss the ramifications for leptogenesis and lepton flavour violation.