Discrete flavour and CP symmetries in light of JUNO and neutrino global fit

TL;DR

This paper tests predictions of non-Abelian discrete flavour and CP symmetries against JUNO and global neutrino data, identifying which symmetry breaking patterns are compatible with current measurements and exploring future experimental constraints.

Contribution

It provides a comprehensive statistical analysis of lepton mixing patterns derived from discrete flavour and CP symmetries using recent neutrino data, highlighting which models are favored or disfavored.

Findings

JUNO data can exclude certain symmetry breaking patterns.

Synergy of JUNO, DUNE, and T2HK enhances tests of flavour symmetry models.

Best fit values and allowed ranges for mixing parameters are established.

Abstract

Working within the reference three-neutrino mixing framework, we confront the lepton mixing predictions derived using non-Abelian discrete flavour and CP symmetries with the first JUNO data on the solar neutrino mixing parameters $\sin^2\theta_{12}$ and with the results of the latest global neutrino data analysis. We focus on symmetry breaking patterns for which the lepton PMNS mixing matrix depends only on one or two free real parameters. Performing a comprehensive statistical analysis in each of the considered cases, we report the best fit values, the $3\sigma$ C.L. allowed ranges and the $\chi^2$-distributions of the lepton mixing observables - the three mixing angles and the three CP-violation phases. We find that the JUNO measurements can disfavour or rule out a number of the mixing patterns associated with specific types of breaking of the discrete flavour and CP symmetries. The synergy of JUNO, DUNE and T2HK data can provide an exhaustive test of the considered approach to lepton mixing based on non-Abelian discrete lepton flavour symmetries combined with the CP symmetry.