2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/206093A 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.7 pages, 2 encapsulated postscript figures, submitted to PRLHigh Energy Physics - Experimenttext