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 update our previous analysis of the 3±01/2 decay mode by the addition of new data to obtain an improved upper limit on the 1/2 mass of 143 MeV/c2 at the 95% confidence level. © 1985 The American Physical Society.

We have set an upper limit on the mass from a study of the four-pion invariant-mass distribution in the decay 3 0. We obtain the limit m <164 MeV/c2 at 95% confidence level. © 1984 The American Physical Society.

The average lifetime of bottom hadrons was measured with the Mark II vertex detector at the storage ring PEP. The lifetime was determined by measuring the impact parameters of leptons produced in bottom decays. τb=(12.0-3.6+4. 5±3.0)×10-13 sec was found. © 1983 The American Physical Society.

This paper presents a study of events produced in 29-GeV electron-positron annihilation in which there are just two noncollinear charged particles, no detected photons, and two or more undetected particles. These events can be explained by attributing them primarily to the reactions e+e-'e+e-e+e- and e+e-'e+e-+- where just two particles appear in the Mark II detector. There is no evidence for unconventional sources for such events. © 1986 The American Physical Society.

A search has been made for the inclusive production of J ψ (3.1) and Υ{hooked} (9.4) mesons in e+e- interactions at 29 GeV, via their decay into two leptons. No signal is observed in the J ψ region, nor in the Υ{hooked} region. The limits on the cross sections are σ(e+e- → ψX) < 4.4 × 10-36cm2, and σ(e+e- → Υ{hooked}X) < 4.7 × 10-36 cm2. The same data yield limits on the branching ratios for the b quark BR (b → ψX) < 4.9% and BR (b → ℓ+ℓ-X) < 0.8%. © 1983.

A measurement of jet energy spread in the reaction e+e- → hadrons is presented. Using a jet calculus model for the jet development we determine the variation of the strong coupling constant with respect to momentum transfer. The observed variation is consistent with that expected for QCD over a wide range of momentum transfers. This method alone is not sufficient to distinguish QCD from simple limited transverse momentum models. © 1983.

With use of three-prong τ decays observed by the Mark II detector at the Stanford Linear Accelerator Center (PEP), the τ lifetime is measured to be (4.6±1.9)×10-13 sec. © 1982 The American Physical Society.

The charged-particle multiplicities of hadronic events deriving from produced bottom or charm quarks have been measured in the Mark II detector at PEP in e+e- annihilation at 29 GeV. For events containing one semileptonic and one hadronic weak decay, we find multiplicities of 15.20.50.7 for bottom and 13.00.50.8 for charm. The corresponding multiplicities of charged particles accompanying the pair of heavy hadrons are 5.20.50.9 for bottom, and 8.10.50.9 for charm. © 1985 The American Physical Society.