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

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.