Search for the Lepton-Flavor-Violating Decay ${\ensuremath{\tau}}^{\ensuremath{-}}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{\ensuremath{-}}\ensuremath{\eta}$ at Belle

Search for the Lepton-Flavor-Violating Decay $τ^{-} \to μ^{-} η$ at Belle

Y. Enari et al. (Belle Collaboration)

Phys. Rev. Lett. 93, 081803 – Published 19 August 2004

Abstract

We have searched for the lepton flavor violating decay $τ^{-} \to μ^{-} η$ using a data sample of $84.3 {f b}^{- 1}$ accumulated with the Belle detector at KEK. The $η$ meson was detected through the decay modes: $η \to γ γ$ and $π^{+} π^{-} π^{0}$ . No signal candidates are found, and we obtain an upper limit for the branching fraction $B (τ^{-} \to μ^{-} η) < 3.4 \times 10^{- 7}$ at the 90% confidence level.