Searches for Lepton Flavor Violation in the Decays<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mi>τ</mml:mi><mml:mo>±</mml:mo></mml:msup><mml:mo>→</mml:mo><mml:msup><mml:mi>e</mml:mi><mml:mo>±</mml:mo></mml:msup><mml:mi>γ</mml:mi></mml:math>and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mi>τ</mml:mi><mml:mo>±</mml:mo></mml:msup><mml:mo>→</mml:mo><mml:msup><mml:mi>μ</mml:mi><mml:mo>±</mml:mo></mml:msup><mml:mi>γ</mml:mi></mml:math>

Searches for lepton-flavor-violating decays of a tau lepton to a lighter mass lepton and a photon have been performed with the entire data set of (963+/-7)x10{6} tau decays collected by the BABAR detector near the Upsilon(4S),upsilon(3S) and Upsilon (2S) resonances.

Abstract

Searches for lepton-flavor-violating decays of a $\ensuremath{\tau}$ lepton to a lighter mass lepton and a photon have been performed with the entire data set of $(963\ifmmode\pm\else\textpm\fi{}7)\ifmmode\times\else\texttimes\fi{}{10}^{6}\text{ }\text{ }\ensuremath{\tau}$ decays collected by the BABAR detector near the $\ensuremath{\Upsilon}(4S)$, $\ensuremath{\Upsilon}(3S)$ and $\ensuremath{\Upsilon}(2S)$ resonances. The searches yield no evidence of signals and we set upper limits on the branching fractions of $\mathcal{B}({\ensuremath{\tau}}^{\ifmmode\pm\else\textpm\fi{}}\ensuremath{\rightarrow}{e}^{\ifmmode\pm\else\textpm\fi{}}\ensuremath{\gamma})&lt;3.3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}8}$ and $\mathcal{B}({\ensuremath{\tau}}^{\ifmmode\pm\else\textpm\fi{}}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{\ifmmode\pm\else\textpm\fi{}}\ensuremath{\gamma})&lt;4.4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}8}$ at 90% confidence level.