Neutrino Masses and Mixings from Quark Mass Hierarchies

TL;DR

This paper explores how neutrino masses and mixings can naturally arise from quark mass hierarchies within SO(10) models featuring a fourth generation, highlighting the connection between quark and neutrino mass structures.

Contribution

It demonstrates that in SO(10) models with a vectorial fourth generation, neutrino mass hierarchies emerge naturally from quark mass hierarchies, providing a novel explanation for the normal hierarchy.

Findings

Neutrino mass hierarchy is linked to quark mass hierarchy mismatch.

Effective CP phases in quarks and neutrinos are unrelated.

Model accommodates a natural normal neutrino hierarchy.

Abstract

In SO(10) models with a vectorial fourth generation of down quarks and leptons, the structure of the neutrino Majorana and Dirac mass matrices generically coincide with those of up- and down-quarks, respectively. Then the small neutrino mass hierarchy follows from the mismatch of the up and down quark mass hierarchies and we can accommodate naturally a normal hierarchy. The effective CP violating phases in the quark sector, neutrino oscillations and leptogenesis are unrelated.