The τ lifetime was measured with the Mark II vertex detector at the storage ring PEP. ττ=(3.20±0.41±0.35)×10-13 sec was found, which agrees well with e-μ-τ university. © 1983 The American Physical Society.

We present a high statistics measurement of the branching ratio for the decay τ-→π-μτ using data obtained with the Mark II detector at the SLAC e+e- storage ring SPEAR. We have used events from the center-of-mass energy region 3.52 to 6.7 GeV to determine that B(τ-→π-μτ)=0.117±0.004±0.018. From electron-muon events in the same data sample, we have determined that B(τ-→π-μτ) B(τ-→e--μeμτ)=0.66±0.03±0.11. We present measurements of the mass and spin of the τ and the mass of the τ neutrino based, for the first time, on a hadronic decay mode of the τ. © 1982.

Energy correlations have been measured with the MARK II detector at the PEP storage ring (Stanford Linear Accelerator Center) at c.m. energy of 29 GeV and are compared to first-order QCD predictions. Fragmentation processes are significant and limit the precision with which the first-order strong-coupling constant can be determined. © 1982 The American Physical Society.

The Mark II detector at SPEAR has been used to study D-meson production in e+e- annihilation at center-of-mass energies between 3.8 and 6.7 GeV. The neutral and charged D mesons are identified from their K and K decay modes. Measurements of RD and of the inclusive differential cross section s ddz are presented. The quasi-two-body cross sections DD, D*D, and D*D* are derived from an overall fit to the D recoil spectra. No evidence was found for the associated production of charmed mesons and charmed baryons. © 1982 The American Physical Society.

The differential cross sections for lepton pair production in e+e- annihilation at 29 GeV have been measured and found to be in good agreement with the standard model of the electroweak interaction. With the assumption of e-μ-τ universality, the weak neutral-current couplings are determined to be ga2=0.23±0.05 and gv2=0.03±0.04. © 1983 The American Physical Society.

The D Cabibbo-suppressed decay modes -+ and K-K+ have been observed and the following ratios of D partial decay widths have been measured: (D-+)(DK-+)=0.0330.015 and (DK-K+)(DK-+)=0.1130.030. © 1979 The American Physical Society.

The prompt photon decay (3095)+-+- has been studied with the Mark II detector at SPEAR. This channel is found to contain a 00 component with 00 masses concentrated between 1.4 and 2.0 GeV/c2. The branching fraction for the 00 decay with masses less than 2.0 GeV/c2 is measured to be (1.25±0.35±0.40)×10-3. © 1982 The American Physical Society.

This Letter presents a measurement of the decay τ-→ρ-ντ using data obtained with the Mark II detector at SPEAR. In the center-of-mass energy region 4.5<~Ec.m.<~6.0 GeV 85 events are observed in which a charged ρ was found in coincidence with either an electron or a muon. It was determined that B(τ-→ρ-ντ)=(20.5±4.1)% and the ratio B(τ-→ρ-ντ)B(τ-→e-ντν̄e)=1.11± 0.23. © 1979 The American Physical Society.

Direct electrons are observed in baryon events produced in e+e- annihilation at center-of-mass energies above the c»c threshold. These events are attributed to charmed-baryon pair production and subsequent c semileptonic decay. Various semileptonic branching ratios of the c are determined, including B(ce+X)=(4.5 1.7)%. © 1982 The American Physical Society.

The production of the charmed meson state D*+ has been observed in e+e- annihilation at 29 GeV. The fragmentation function for charmed quarks appears to be peaked about z=0.5. © 1982 The American Physical Society.