Radiative seesaw corrections and charged-lepton decays in a model with soft flavour violation

TL;DR

This paper analyzes how one-loop radiative corrections significantly impact the predictions of lepton-flavour-violating decay rates in a two-Higgs-doublet model with the type-I seesaw mechanism, emphasizing their importance in accurate modeling.

Contribution

It demonstrates the crucial role of one-loop radiative corrections in accurately predicting lepton-flavour-violating decay branching ratios in a specific extended Higgs model.

Findings

Radiative corrections can change branching ratios by several orders of magnitude.

They may explain the suppression of $ ext{BR}(\mu^- o e^- e^+ e^-)$ compared to tau decays.

Accounting for these corrections is essential for reliable numerical predictions.

Abstract

We consider the one-loop radiative corrections to the light-neutrino mass matrix and their consequences for the predicted branching ratios of the five lepton-flavour-violating decays $\ell_1^- \to \ell_2^- \ell_3^+ \ell_3^-$ in a two-Higgs-doublet model furnished with the type-I seesaw mechanism and soft lepton-flavour violation. We find that the radiative corrections are very significant; they may alter the predicted branching ratios by several orders of magnitude and, in particular, they may help explain why $\mbox{BR}(\mu^- \to e^- e^+ e^-)$ is strongly suppressed relative to the branching ratios of the decays of the $\tau^-$. We conclude that, in any serious numerical assessment of the predictions of this model, it is absolutely necessary to take into account the one-loop radiative corrections to the light-neutrino mass matrix.