A Neutrino Mass Matrix with Vanishing $\mu$--$\mu$ and $\tau$--$\tau$ Entries

TL;DR

This paper explores a specific neutrino mass matrix with two zero entries, emphasizing the role of the CP-violating phase, and links it to a symmetry-based see-saw model with three Higgs doublets.

Contribution

It proposes a new two-zero neutrino mass matrix ansatz derived from a softly-broken muon-tau symmetry in a three-Higgs-doublet see-saw model.

Findings

The ansatz predicts observable consequences for neutrino oscillations.

The CP-violating phase δ significantly influences the mass matrix structure.

The model connects symmetry breaking to neutrino mass patterns.

Abstract

We revisit our earlier proposal for the form of the neutrino mass matrix: a two-zero ansatz wherein the CP-violating PMNS phase $\delta$ plays a surprisingly important role. We review its observable consequences and show how our ansatz follows from a softly-broken symmetry (muon number minus tau lepton number) in a see-saw model with three Higgs doublets.