Upper Bound on the Decay τ→μγ from the Belle Detector

We have performed a search for the lepton-flavor-violating decay τ → μγ using a data sample of 86.3 fb - 1 accumulated by the Belle detector at KEK. No evidence for a signal is seen, and we set an upper limit for the branching fraction of B(τ → μγ) < 3.1 × 10 - 7 at the 90% confidence level.