Lepton flavor violation in minimal flavor violation extensions of the seesaw

TL;DR

This paper explores two minimal flavor violation frameworks compatible with the seesaw mechanism, analyzing their implications for lepton flavor violation observables and their predictive power.

Contribution

It compares two minimal flavor violation schemes in the seesaw context, highlighting their differences and implications for LFV observables.

Findings

Two distinct MFV implementations compatible with seesaw are identified.

The schemes differ in CP violation allowance and flavor group structure.

Implications for LFV observables vary between the two frameworks.

Abstract

A minimal flavour violation hypothesis for leptons can be implemented essentially in two ways that are compatible with a type-I seesaw structure with three heavy singlet neutrinos $N$, and that satisfy the requirement of being predictive, in the sense that all lepton flavor violating (LFV) effects can be expressed in terms of low energy observables. The first realization is CP conserving and is based on the flavor group $SU(3)_e\times SU(3)_\ell\times O(3)_N$ (being $e$ and $\ell$ the SU(2) singlet and doublet leptons). The second realization allows for CP violation and is based on $SU(3)_e\times SU(3)_{\ell+N}$. I review the main features of the two schemes and point out their different implications for LFV observables.