Aspects of Leptonic Flavour Mixing

TL;DR

This paper reviews theoretical ideas explaining leptonic flavor mixing, focusing on predictability, fixed-point relations, radiative masses, and flavor symmetries, comparing anarchy-based models with discrete symmetry models.

Contribution

It analyzes the predictability of various models of leptonic mixing, emphasizing fixed-point relations, radiative mass mechanisms, and flavor symmetries, with a focus on two main classes of models.

Findings

Anarchy models can reproduce quark and lepton spectra in GUT frameworks.

Discrete flavor symmetry models offer more predictive power for leptonic mixing.

Fixed-point relations provide insights into mixing angles and phases.

Abstract

Since the discovery of neutrino oscillations many ideas have been put forward to explain the special features of the leptonic mixing and the differences with respect to the quark sector. In this talk I review some of these proposals, emphasizing especially their predictability. In the light of the new data, I first revisit fixed-point relations among mixing angles and phases. Then I briefly comment on radiative neutrino masses. Finally I discuss the role of flavour symmetries. Given the very many existing models I focus on two classes of models. On the one hand I illustrate the ability of models based on a generalization of the anarchy idea in reproducing the main features of both the quark and the lepton spectrum, also in a GUT framework. On the other hand I discuss less ambitious but more predictive models based on discrete flavour symmetries, centered on the properties of the leptonic mixing matrix.