Leptonic Sum Rules from Flavour Models with Modular Symmetries

TL;DR

This paper derives new leptonic sum rules in models with modular symmetries, linking neutrino masses, phases, and mixing parameters, and explores their experimental implications.

Contribution

It introduces novel sum rules in modular symmetry models that connect neutrino masses, phases, and mixing angles, providing analytical expressions and testable predictions.

Findings

Neutrino mass sum rules involving Majorana phases.

Mixing sum rules connecting angles and CP phase.

Predictions for neutrino experiments based on derived sum rules.

Abstract

Sum rules in the lepton sector provide an extremely valuable tool to classify flavour models in terms of relations between neutrino masses and mixing parameters testable in a plethora of experiments. In this manuscript we identify new leptonic sum rules arising in models with modular symmetries with residual symmetries. These models simultaneously present neutrino mass sum rules, involving masses and Majorana phases, and mixing sum rules, connecting the mixing angles and the Dirac CP-violating phase. The simultaneous appearance of both types of sum rules leads to some non-trivial interplay, for instance, the allowed absolute neutrino mass scale exhibits a dependence on the Dirac CP-violating phase. We derive analytical expressions for these novel sum rules and present their allowed parameter ranges as well as their predictions at upcoming neutrino experiments.