Maximal CP violation in lepton mixing from a model with Delta(27) flavour symmetry

TL;DR

This paper introduces a mechanism within models based on Delta(27) flavour symmetry that predicts maximal CP violation and atmospheric neutrino mixing, with implications for neutrino mass scale and neutrinoless double-beta decay.

Contribution

It presents a novel mechanism enforcing specific lepton mixing matrix properties within Delta(27)-based models, leading to maximal CP violation and new predictions for neutrino physics.

Findings

Maximal atmospheric neutrino mixing and CP violation predicted.

Correlation between neutrino mass scale and neutrinoless double-beta decay.

Ambiguous determination of the absolute neutrino mass scale.

Abstract

We propose a simple mechanism which enforces |U_{mu j}| = | U_{tau j}| forall j = 1,2,3 in the lepton mixing matrix U. This implies maximal atmospheric neutrino mixing and a maximal CP-violating phase but does not constrain the reactor mixing angle theta_{13}. We implement the proposed mechanism in two renormalizable seesaw models which have features strongly resembling those of models based on a flavour symmetry group Delta(27). Among the predictions of the models, there is a determination, although ambiguous, of the absolute neutrino mass scale, and a stringent correlation between the absolute neutrino mass scale and the effective Majorana mass in neutrinoless double-beta decay.