Measurement of the tau lifetime

We have used a high-resolution drift chamber in the Mark II detector at the SLAC storage ring PEP to measure the lifetime of {τ} leptons produced in e⁺{e}^{{{-}}}$ annihilations at 29 GeV. Based on the flight-path distribution of 807 three-prong {τ} decays, the lifetime is found to be (2.88±{}0.16 ±{}0.17)×{}10^-13 sec, in agreement with expectations for e-{μ}-{τ} universality.