Properties of the proposed τ charged lepton

Abstract

The anomalous eμ and 2-prong μx events produced in e +e − annihilation are used to determine the properties of the proposed τ charged lepton. We find the τ mass is 1.90 ± 0.10 GeV/ c 2; the mass of the associated neutrino, ν τ , is less than 0.6 GeV/ c 2 with 95% confidence; V - A coupling is favored over V + A coupling for the τ − ν τ current; and the leptonic branching ratios are 0.186 ± 0.010 ± 0.028 from the eμ events and 0.175 ± 0.027 ± 0.030 from the μx events where the first error is statistical and the second is systematic.