Search for Lepton Flavor Violation in the Decay tau ->mu gamma

A search for the nonconservation of lepton flavor number in the decay tau ->mu gamma has been performed using 2.07 x 10^8 e+e- ->tau+ tau- events produced at a center-of-mass energy near 10.58 GeV with the BABAR detector at the PEP-II storage ring. We find no evidence for a signal and set an upper limit on the branching ratio of BR(tau ->mu gamma)<6.8 x 10^-8 at 90% confidence level.