A search for neutrinoless tau decays to three leptons

Using approximately 350 million tau+tau- pair events recorded with the BaBar detector at the Stanford Linear Accelerator Center between 1999 and 2006, a search has been made for neutrinoless, lepton-flavor violating tau decays to three lighter leptons. All six decay modes consistent with conservation of electric charge and energy have been considered. With signal selection efficiencies of 5--12%, we obtain 90% confidence level upper limits on the branching fraction B(tau → ℓℓℓ) in the range (4--8) x 10-8.