The hadronic final state in e+e−e^{+}e^{-} annihilation at c.m. energies of 13, 17 and 27.4 GeV

Results on the hadronic final state in e/sup +/e/sup -/ annihilation at 13, 17 and 27.4 GeV are presented. There is no compelling evidence for the existence of the t quark in these data, which are in general agreement with a simple quark parton model. Some tentative indications of QCD effects are observed in the p/sub T//sup 2/ distributions

PRODUCTION AND PROPERTIES OF THE tau LEPTON IN e+ e- ANNIHILATION AT c.m. ENERGIES FROM 12-GeV TO 31.6-GeV

We have observed τ production in e+e− annihilation at centre-of-mass energies between 12 and 31.6 GeV with cross sections in agreement with the QED τ-pair cross section. Branching ratios for τ decay have been measured and are consistent with the world averages. We have determined the cutoff parameters of QED Λ+ (Λ−) to be > 73 GeV (82 GeV) and have obtained an upper limit on the τ lifetime of 1.4 × 10−12 s(95% CL)