Limits on<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>τ</mml:mi></mml:math>lepton-flavor violating decays into three charged leptons

Abstract

A search for the neutrinoless, lepton-flavor violating decay of the $\ensuremath{\tau}$ lepton into three charged leptons has been performed using an integrated luminosity of $468\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ collected with the BABAR detector at the PEP-II collider. In all six decay modes considered, the numbers of events found in data are compatible with the background expectations. Upper limits on the branching fractions are set in the range $(1.8--3.3)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}8}$ at 90% confidence level.