R. P. Hamilton

Measurement of the Branching Fractions for D0 ---> pi- e+ electron-neutrino and D0 ---> K- e+ electron-neutrino and Determination of (V (c d) / V (c s))**2

Measurements of the exclusive branching fractions B(D^0→π^-e^+ν_e) and B(D^0→K^-e^+ν_e), using data collected at the ψ(3770) with the Mark III detector at the SLAC e^+e^- storage ring SPEAR, are used to determine the ratio of the Kobayashi-Maskawa matrix elements │V_(cd)/V_(cs)│^2 =0.057_(-0.015)^(+0.038)±0.005.

Resonant substructure in Kππ decays of charmed D mesons

Abstract Dalitz plot analyses of four Kππ decays of the D 0 and D + mesons are presented. The relative amounts of K ∗ π, Kϱ and non-resonant Kππ in each decay mode are determined, and isospin amplitudes and phases are derived. These results are compared with predictions from QCD. The K − π + π + mode has a non-uniform, non-resonant contribution; attempts to fit this distribution are described.

Measurement of the

We report a new measurement of the D∗ branching ratios, using data obtained with the Mark III detector at the e^+e^− storage ring SPEAR at s=4.14GeV. A fit to the recoil mass squared spectrum of D mesons reconstructed through the decay modes K^−π^+π^+ and K^−π^+ is used to extract the D^(∗+) → γD^+, π^0D^+, π^+D^0 and D^(∗0) → γD^0, π^0D^0 branching ratios.

D^*

Abstract This paper describes the design, construction and performance of the Mark III, a new general purpose large solid angle spectrometer at SPEAR, the SLAC 2–8 GeV e+e− storage ring. The detector has been designed for the study of exclusive final states in e+e− annihilation, which requires large solid angle coverage combined with charged particle momentum resolution, particle identification, and photon detection efficiency at low energies.

Branching Ratios

Abstract A search for the lepton family number violating decay D 0 → μ e is reported. No signal is observed in a data sample of 9.3 pb −1 collected at the ζ (3770) resonance with the MARK III detector, where 0.18±0.06±0.05 background events are expected. A 90% confidence level upper limit on the branching fraction B (D 0 → μ e) of 1.5 × 10 −4 is obtained.

The Mark III spectrometer

Abstract We describe below the design, construction and performance of the end cap shower counters of the MARK III detector. These counters, made up of layers of aluminum proportional tubes sandwiched between lead sheets, achieve a position resolution for electrons or photons of about 7 mm × 9 mm using charge division for the position measurement along the wire direction. The energy resolution for fully contained electron and photon showers is σ E E = 17% √E . The counters are segmented into twelve individual readouts in depth, allowing the very good pattern recognition needed for the separation of nearby showers. The total depth of the counter, twelve radiation lengths, is adequate for the SPEAR energy range. Good photon detection efficiency extends to energies below 100 MeV.

A search for the lepton family number violating decay D0→μe

Measurements of the exclusive branching fractions B(D^0→π^-e^+ν_e) and B(D^0→K^-e^+ν_e), using data collected at the ψ(3770) with the Mark III detector at the SLAC e^+e^- storage ring SPEAR, are used to determine the ratio of the Kobayashi-Maskawa matrix elements │V_(cd)/V_(cs)│^2 =0.057_(-0.015)^(+0.038)±0.005.

The endcap shower counters for the MARK III detector

Measurements of the exclusive branching fractions B(D^0→π^-e^+ν_e) and B(D^0→K^-e^+ν_e), using data collected at the ψ(3770) with the Mark III detector at the SLAC e^+e^- storage ring SPEAR, are used to determine the ratio of the Kobayashi-Maskawa matrix elements │V_(cd)/V_(cs)│^2 =0.057_(-0.015)^(+0.038)±0.005.

Measurement of the branching fractions forD0→π−e+νeandD0→K−e+νeand determination of ‖Vcd/Vcs‖2

A search for the decay of the charmed meson /ital D//sup 0//r arrow//bar K//sup 0/e/sup +/e/sup /minus// is presented, based on data collected at the /psi/(3770) resonance with the Mark III detector at the SLAC storage ring SPEAR. No evidence for this process is found, resulting in an upper limit on the decay branching ratio of 1.7/times/10/sup /minus/3/ at the 90% confidence level.

Measurement of the branching fractions for D0--> pi -e+ nu e and D0-->K-e+ nu e and determination of ||Vcd/Vcs||2.

A search for the decay of the charmed meson /ital D//sup 0//r arrow//bar K//sup 0/e/sup +/e/sup /minus// is presented, based on data collected at the /psi/(3770) resonance with the Mark III detector at the SLAC storage ring SPEAR. No evidence for this process is found, resulting in an upper limit on the decay branching ratio of 1.7/times/10/sup /minus/3/ at the 90% confidence level.