Search for Lepton-Flavor and Lepton-Number Violation in the Decay τ−→ℓ∓h±h'−

Abstract

A search for lepton-flavor and lepton-number violation in the decay of the tau lepton into one charged lepton and two charged hadrons is performed using 221.4 fb − 1 of data collected at an e + e − center-of-mass energy of 10.58 GeV with the BABAR detector at the SLAC PEP-II storage ring. In all 14 decay modes considered, the observed data are compatible with background expectations, and upper limits are set in the range B ( τ → ℓ h h ′ ) < ( 0.7 − 4.8 ) × 10 − 7 at 90% confidence level.