Supersymmetric lepton flavor violation in low-scale seesaw models

Abstract

We study a new supersymmetric mechanism for lepton flavor violation in $\ensuremath{\mu}$ and $\ensuremath{\tau}$ decays and $\ensuremath{\mu}\ensuremath{\rightarrow}e$ conversion in nuclei, within a minimal extension of the minimal supersymmetric standard model with low-mass heavy singlet neutrinos and sneutrinos. We find that the decays $\ensuremath{\mu}\ensuremath{\rightarrow}e\ensuremath{\gamma}$, $\ensuremath{\tau}\ensuremath{\rightarrow}e\ensuremath{\gamma}$ and $\ensuremath{\tau}\ensuremath{\rightarrow}\ensuremath{\mu}\ensuremath{\gamma}$ are forbidden in the supersymmetric limit of the theory, whereas other processes, such as $\ensuremath{\mu}\ensuremath{\rightarrow}eee$, $\ensuremath{\mu}\ensuremath{\rightarrow}e$ conversion, $\ensuremath{\tau}\ensuremath{\rightarrow}eee$ and $\ensuremath{\tau}\ensuremath{\rightarrow}e\ensuremath{\mu}\ensuremath{\mu}$, are allowed and can be dramatically enhanced several orders of magnitude above the observable level by potentially large neutrino Yukawa coupling effects. The profound implications of supersymmetric lepton flavor violation for present and future experiments are discussed.