Search for Lepton-Flavor Violation in the Decay<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>ℓ</mml:mi><mml:mo>−</mml:mo></mml:msup><mml:msup><mml:mi>ℓ</mml:mi><mml:mo>+</mml:mo></mml:msup><mml:msup><mml:mi>ℓ</mml:mi><mml:mo>−</mml:mo></mml:msup></mml:math>

A search for the lepton-flavor-violating decay of the tau into three charged leptons has been performed using 91.5 fb(-1) of data collected at an e(+)e(-)center-of-mass energy around 10.58 GeV with the BABAR detector at the SLAC storage ring PEP-II.

Abstract

A search for the lepton-flavor-violating decay of the tau into three charged leptons has been performed using $91.5\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of data collected at an ${e}^{+}{e}^{\ensuremath{-}}$center-of-mass energy around $\mathrm{10.58}\text{ }\text{ }\mathrm{GeV}$ with the BABAR detector at the SLAC storage ring PEP-II. 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 $(1--3)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}7}$ at 90% confidence level.