In a study of (3684) radiative decays with the Mark II detector at SPEAR, the decay sequence c (2980) is observed, with the c (2980) decaying into several completely reconstructed hadronic modes. A mass M=29808 MeV/c2 and a width <40 MeV/c2 (90%) confidence level) are obtained, and estimates of some of the decay branching ratios are presented. © 1980 The American Physical Society.

The inclusive and 0 momentum distributions at the have been measured. Using these data and estimates of production, it is found that (4.1 0.8)% of decays contain a direct photon with energy greater than 60% of the beam energy. The expected momentum distribution for direct photons calculated to lowest order in quantum chromodynamics is qualitatively different from that observed in the data. © 1980 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.

We report a measurement of the cross section for the process γγ→π+π- at invariant masses 500 MeV/c2 < mππ<2000 MeV/c2. A value for the radiative width of the f(1270) tensor meson Γf→γγ = 3.6 ± 0.3 ± 0.5 KeV (helicity λ = 2) has been obtained from a fit to the observed ππ mass spectrum. © 1981.

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.

A peak in the pK-+ and p»K+- invariant-mass spectra at 2.2850.006 GeV/c2 is observed, which is associated with the lowest-lying charmed baryon (c). A cross section times branching ratio of 0.0370.012 nb at Ec.m.=5.2 GeV is measured with a substantial fraction of the events produced with an equal recoiling mass. New measurements of inclusive p and cross sections are also presented, allowing an estimate of the branching ratio B(c+pK-+)=0.0220.010. © 1980 The American Physical Society.

Measurements of ψ(3097) and ψ′(3686) branching fractions for selected hadronic decays are presented. The ratio of ψ′ to ψ branching fractions for these decays is consistent with the ratio of branching fractions to lepton pairs, with the exception of the decays to pπ and K*K for which this ratio is substantially smaller. © 1983 The American Physical Society.

This Letter presents a measurement of the branching fraction for the Cabibbo-suppressed decay -K*-(892) with use of data obtained with the Mark-II detector at SPEAR. Eleven events containing a K*(892) in coincidence with a muon or an electron of opposite charge were found in data which span the center-of-mass energy region 4.2

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.

Copious production of S* decaying into π+π- is observed in ψ decay. (974 ± 4 -i14 ± 5) MeV, consistent with the parameters extracted from couplede channel; fits to pheripheral π+π- and K+K- production experiments. The inclusive branching ratio for ψ → S* + X is found to be (0.42 ± 0.08)%. © 1981.