Measurement of the topological branching fractions of the τ lepton at LEP

Abstract Using data collected with the L3 detector at LEP from 1992 to 1995 on the Z peak, we determine the branching fractionsof the τ lepton into one, three and five charged particles to be: B (τ→( 1-prong ))=85.274±0.105±0.073%, B (τ→( 3-prong ))=14.556±0.105±0.076%, B (τ→( 5-prong ))=0.170±0.022±0.026%. The first uncertainties are statistical and the second systematic. The accuracy of these measurements alone is similar to that of the current world average.