Effects of virtual Majorana neutrinos on charged Lepton Flavor Violation decays from a seesaw variant with radiatively induced light neutrino masses

TL;DR

This paper explores how virtual Majorana neutrinos in a radiative seesaw model can induce charged lepton flavor violation decays, with potential detectability at current and future experiments.

Contribution

It introduces a radiative seesaw variant linking neutrino masses to lepton flavor violation, analyzing parameter space and experimental prospects for detecting these effects.

Findings

$ ext{BR}(oldsymbol{ ext{mu} o e ext{ gamma}})$ depends on heavy neutrino mass

Non-unitary effects constrained to $|oldsymbol{ exteta_{ ext{mu} e}}| extless 10^{-6}$

Current and future experiments could observe these lepton flavor violating decays

Abstract

Lepton flavor violating decays $\ell_{\alpha} \to \ell_{\beta} \gamma$, being forbidden in the Standard Model framework, provide a sensitive probe for new physics. We study these processes in a seesaw variant in which small neutrino masses are generated radiatively. By analyzing the parameter space constrained by electroweak precision data, we investigate the correlation between these decays and non-unitary effects from TeV-scale heavy neutrinos. According to our results, $\mu \to e \gamma$ is the most promising channel for new physics searches, with the bound $|\eta_{\mu e}| \lesssim 10^{-6}$ obtained for non-unitary effects in this radiative seesaw variant. Our estimations of $\mathcal{BR} \left( \mu \to e \gamma \right)$, which depends on the mass of the heavy neutrinos, shows that both current and future experimental facilities might be sensitive to these effects.