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

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 $\mathcal{B}\mathcal{R}\left(\mu \to e\gamma \right)$, which depends on the mass of the heavy neutrinos, shows that both current and future experimental facilities might be sensitive to these effects.

Comments: 18 pages, 12 figures. References added, typos corrected, discussion added, main results unchanged. Version accepted in JPhysG