Features of Charged Lepton Flavor Violation in an $A_4$ Symmetric Neutrino Mass Model

TL;DR

This paper explores a neutrino mass model based on $A_4$ symmetry, predicting potentially observable meson charged lepton flavor violation decays, contrasting with standard see-saw models where such decays are suppressed.

Contribution

It introduces an $A_4$ symmetric neutrino mass model with tri-bimaximal mixing, showing unique CLFV decay patterns and potential observability of meson CLFV decays.

Findings

Meson CLFV decay amplitudes are uncorrelated with radiative CLFV amplitudes in this model.

Radiative CLFV decay branching ratios are negligibly small.

Meson CLFV decay branching ratios can be large enough for near-future detection.

Abstract

Neutrino flavour oscillations imply that there must be charged lepton flavour violation (CLFV) also. Different neutrino mass models predict different patterns of CLFV decays. Neutrino mass generation through standard see-saw mechanisms leads to the prediction that the branching ratios of meson CLFV decays will always be smaller than the corresponding radiative CLFV decays. In this work, we analyse an interesting neutrino mass model, based on $A_4$ symmetry, in which the symmetry and the symmetry-breaking pattern lead the neutrino mixing matrix to be of tri-bimaximal (TBM) form. In this model, we find that the meson CLFV decay amplitudes are not correlated to the corresponding radiative CLFV amplitudes, unlike in the case of see-saw models. The branching ratios of radiative CLFV decays are predicted to be negligibly small in this model, but those of the meson CLFV decays can be large enough to be observable in the near future.