Lepton flavor violation from right-handed neutrino thresholds

Abstract

Charged lepton flavor violation is reappraised in the context of a supersymmetric seesaw mechanism. It is pointed out that a nontrivial flavor structure of right-handed neutrinos, whose effect has been thus far less studied, can give rise to significant slepton flavor transitions. Under the premise that the neutrino Yukawa couplings are of $\mathcal{O}(1)$, the right-handed neutrino mixing contribution could form a basis of the $\ensuremath{\mu}\ensuremath{\rightarrow}e\ensuremath{\gamma}$ amplitude, which by itself might lead to an experimentally accessible rate, given a typical low-energy sparticle spectrum. Emphasis is placed on the crucial role of the recently measured lepton mixing angle ${\ensuremath{\theta}}_{13}$ as well as the leptonic $CP$-violating phases.