Lepton Flavor Violation and the Tau Neutrino Mass

Abstract

We point out that, in the left-right symmetric model of weak interaction, if $ν_τ$ mass is in the keV to MeV range, there is a strong correlation between rare decays such as $τ\rightarrow 3 μ, τ\rightarrow 3 e$ and the $ν_τ$ mass. In particular, we point out that a large range of $ν_τ$ masses are forbidden by the cosmological constraints on $m_{ν_τ}$ in combination with the present upper limits on these processes.