Confronting the prediction of leptonic Dirac CP-violating phase with experiments

TL;DR

This paper updates models predicting the leptonic Dirac CP-violating phase by applying perturbations to mixing patterns, deriving relations with oscillation angles, and analyzing experimental constraints and future prospects.

Contribution

It introduces a systematic approach to relate perturbed mixing matrices to the CP-phase and provides a model with $A_4$ modular symmetry consistent with current data.

Findings

Constraints on the CP-phase from current experiments.

Relations between CP-phase and oscillation angles.

A viable $A_4$ modular symmetry model.

Abstract

We update and improve past efforts to predict the leptonic Dirac CP-violating phase with models that predict perturbatively modified tribimaximal or bimaximal mixing. Simple perturbations are applied to both mixing patterns in the form of rotations between two sectors. By translating these perturbed mixing matrices to the standard parameterization for the neutrino mixing matrix we derive relations between the Dirac CP-phase and the oscillation angles. We use these relations together with current experimental results to constrain the allowed range for the CP-phase and determine its probability density. Furthermore, we elaborate on the prospects for future experiments probing on the perturbations considered in this work. We present a model with $A_4$ modular symmetry that is consistent with one of the described perturbed scenarios and successfully predicts current oscillation parameter data.