Flavour-symmetric type-II Dirac neutrino seesaw mechanism

TL;DR

This paper introduces a Standard Model extension with A4 flavour symmetry that generates small Dirac neutrino masses via a Type-II seesaw, predicting specific mass relations and mixing parameters.

Contribution

It presents a novel A4-flavour symmetric model for Dirac neutrino masses using a Type-II seesaw mechanism, with specific predictions for neutrino mass ordering and mixing angles.

Findings

Predicts inverted neutrino mass ordering

Requires non-maximal atmospheric mixing angle

Derives correlations between CP phase and neutrino mass

Abstract

We propose a Standard Model extension with underlying A4 flavour symmetry where small Dirac neutrino masses arise from a Type-II seesaw mechanism. The model predicts the "golden" flavour-dependent bottom-tau mass relation, requires an inverted neutrino mass ordering and non-maximal atmospheric mixing angle. Using the latest neutrino oscillation global fit we derive restrictions on the oscillation parameters, such as a correlation between Dirac CP phase and the lightest neutrino mass.