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.

The decay modes with multiple neutral mesons in the final states have been studied with the Mark II detector at the SLAC storage ring PEP. The branching ratio for the decay mode - 20 is found to be consistent with the theoretical expectation. However, the branching ratio for - 30 is found to be inconsistent with the theoretical prediction unless there are other decay modes with multiple neutral mesons in the final states. © 1987 The American Physical Society.

We have searched for the lepton-flavor-violating decay D0e in 204 pb-1 of e+e- annihilation data at Ec.m.=29 GeV from the Mark II detector. No candidates were found; we estimate an upper limit on the cross section times branching ratio of (e+e-D0,D0; inclusive)B(D0e)<0.35 pb at the 90% confidence level. Simple assumptions yield the rough limit B(D0e)<2.1×10-3. AE. © 1987 The American Physical Society.

We use data taken by the Mark II detector at the SLAC storage ring PEP to study inclusive lepton production in e+e- annihilation at 29 GeV. From fits to the inclusive lepton momentum and transverse-momentum spectra we measure the semileptonic branching ratios for charm and bottom hadrons. We also determine with good precision the mean value of the bottom fragmentation function using both electron and muon samples. © 1988 The American Physical Society.

Inclusive - production in e+e- annihilation at 29 GeV has been measured with the Mark II detector. From an integrated luminosity of 207 pb-1, we determine a production rate of 0.0170.0040.004 -++ per hadronic event. A search for *0(1530)-+ leads to an upper limit of N(*0)/N(-)<0.35 at a 90% confidence level. © 1987 The American Physical Society.

We have measured the K0+K0 inclusive cross section in e+e- annihilation at 29 GeV with the Mark II detector SLAC PEP. We find 1.270.030.15 K0+K0 per hadronic event. We have also used time-of-flight particle identification to measure the K rate over the momentum range 300900 MeV/c. © 1985 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.

The process e+e-e+e-(), where one electron scatters at a small angle, is studied with data from the Mark II detector at the SLAC storage ring PEP. The data are in excellent agreement with a Monte Carlo calculation and include a large contribution from order 4. The ratio of measured to calculated cross sections is R=0.9930.0170.015, where the first error is statistical and the second systematic. This is a sensitive test of the calculation of the dominant background for neutrino-counting experiments. © 1989 The American Physical Society.

A search for single electrons from the decay of singly produced scalar electrons has been made at the PEP storage ring at SLAC. No events of this type have been found in 123 pb-1 of data, resulting in a cross-section limit of less than 2.4×10-2 pb within the detector acceptance, and a 95%-confidence-level lower limit on the scalar-electron mass of 22.2 GeV/c2. © 1983 The American Physical Society.

We have studied several features of the production of charged-hardon pairs by γγ collisions. We have measured the f0 partial width Γf0→γγ(Q2) for Q2 in the range 0