Charged Lepton Flavor Violation in a class of Radiative Neutrino Mass Generation Models

TL;DR

This paper studies charged lepton flavor violation in three-loop radiative neutrino mass models, finding specific suppression patterns among processes that could reveal the neutrino mass generation mechanism.

Contribution

It identifies the suppression of certain LFV processes due to diagram cancellations in a class of three-loop neutrino mass models, providing a potential experimental signature.

Findings

$ ext{BR}(oldsymbol{ ext{mu} o ext{e} ext{gamma}})$ and $ ext{CR}(oldsymbol{ ext{mu-e}})$ are highly suppressed.

$ ext{BR}(oldsymbol{ ext{mu} o ext{e} ext{e} ar{ ext{e}}})$ remains comparatively larger.

Pattern of LFV processes can indicate the radiative origin of neutrino masses.

Abstract

We investigate charged lepton flavor violating processes $\mu\rightarrow e \gamma$, $\mu\rightarrow e e \overline{e}$ and $\mu-e$ conversion in nuclei for a class of three-loop radiative neutrino mass generation models with electroweak multiplets of increasing order. We find that, because of certain cancellations among various one-loop diagrams which give the dipole and non-dipole contributions in effective $\mu e \gamma$ vertex and Z-penguin contribution in effective $\mu e Z$ vertex, the flavor violating processes $\mu\rightarrow e\gamma$ and $\mu-e$ conversion in nuclei become highly suppressed compared to $\mu\rightarrow e e \overline{e}$ process. Therefore, the observation of such pattern in LFV processes may reveal the radiative mechanism behind neutrino mass generation.