E. I. Shibata

First measurement of Γ(D* +) and precision measurement of m D*+-m D0

We present the first measurement of the D*+ width using 9/fb of e+ e- data collected near the Upsilon(4S) resonance by the CLEO II.V detector. Our method uses advanced tracking techniques and a reconstruction method that takes advantage of the small vertical size of the CESR beam spot to measure the energy release distribution from the D*+ -> D0 pi+ decay. We find Gamma(D*+) = 96 +- 4 (Statistical) +- 22 (Systematic) keV. We also measure the energy release in the decay and compute Delta m = m(D*+) - m(D0) = 145.412 +- 0.002 (Statistical) +- 0.012 (Systematic) MeV/c^2

Rapidity Dependence of the Charged Particle Multiplicity Distributions in e+ e- Annihilation at 29-GeV

Abstract The charged particle multiplicity distribution for e+e− annihilations at s = 29 GeV has been measured using the High Resolution Spectrometer at PEP. The multiplicity distribution, expressed as a function of the mean, shows KNO scaling when compared to e+e− data at other energies. Multiplicity distributions for particles selected in different central rapidity spans are presented. All of these are well presented by the Negative binomial distribution. As the rapidity span is narrowed, the distributions become broader and approach a constant value of the parameter k.

Performance of multiclad scintillating and clear waveguide fibers read out with visible light photon counters

Abstract Measurements have been made of the performance of scintillating fibers read out with visible light photon counters (VLPCs). The light yields of single-clad and multiclad scintillating fibers have been compared. The experiment consisted of 3 m long scintillating fibers of 830 μm diameter optically coupled to 8 m long waveguide fibers of 965 μm diameter read out with HISTE-IV VLPCs. For the case of multiclad scintillating fiber and waveguide, an average of 6.2 photoelectrons was detected from the far end of the scintillating fiber if the fiber end was unmirrored, and 10.2 photoelectrons if the fiber end was mirrored. With this substantial photoelectron yield, minimum-ionizing tracks can be easily detected in fiber arrays, and excellent performance characteristics are expected for the fiber trackers designed for the D0 experiment at the Fermilab Tevatron Collider and the SDC experiment at the SSC Laboratory.

Production cross section and electroweak asymmetry of D* and D mesons produced in e+e- annihilations at 29 GeV

Abstract The production of D * and D mesons has been studied in e + e − annihilations at √s = 29GeV. The data, corresponding to an integrated luminosity of 300 pb −1 , were obtained using the HRS detector at PEP. The cross section is measured to be R (D 0 + D + ) = 2.40±0.35 and we determine the electroweak asymmetry to be −9.9 ± 2.7%, which corresponds to an axial vector coupling constant product g e g c = 0.26 ± 0.07.

Comparison of charged particle multiplicities in quark and gluon jets produced in e+e- annihilation at 29 GeV

The charged particle multiplicities of the quark and gluon jets in the three-fold symmetric e+e− → qqg events at √s = 29 GeV have been studied using the high resolution spectrometer at PEP. A value of 〈n〉g = 6.7−2.1+1.1±1.0 for gluon jet s with an energy of 9.7−2.0+1.5 GeV is measured. The ratio, 〈n〉g/〈n〉q, is 1.29−0.41+0.21±0.20, which i s significantly lower than the value of 94 naively expected from the ration of the gluon-to-quark color charges.

A search for exclusive penguin decays of B mesons

Abstract We have measured upper limits on branching fractions for rare exclusive decays of B mesons arising from one-loop diagrams in the standard model of electroweak interactions. We also obtain an upper limit for the lepton-number-violating decay B 0 → μ ± e ∓ .

Evidence for the decay τ+→π+ηντ

Abstract The inclusive production of η mesons in tau lepton decay has been studied using the High Resolution Spectrometer at the PEP e + e - facility. The data sample corresponds to an integrated luminosity of 300 pb −1 and the storage ring was operated at GeV. The η production appeaars to be only compatible with the decay τ + →π + η ν , which violates isospin and G -parity conservation. The branching ratio of 5.1±1.5% explains much of the current discrepancy between the one-prong topological branching ratio and the sum of the individual one-prong modes.

Neutral K*(890) and ρ0 meson production in e+e- annihilation at ;s=29GeV

Abstract The production of neutral K∗(890) and ρ0 mesons was studied in e+e− annihilation at s =29 GeV using the High Resolution Spectrometer at PEP. Differential cross sections are presented as a function of the scaled energy variable z and compared to π0 and K0 production. The measured multiplicities are 0.84±0.08 ϱ0 mesons and 0.57±0.09 K ∗0 (890) mesons per event for a meson momentum greater than 725 MeV/c. The ratios of vector meson to pseudoscalar meson production for (u,d), s and c quark are compared to predictions of the Lund model.

Charm Quark Production and Fragmentation in

Abstract The electroweak production asymmetry and the decay fragmentation function for e + e − → c c have been measured at s = 29 GeV using charged D ∗ production over the full kinematic range. The data were taken at PEP using the High Resolution Spectrometer. The measured asymmetry is −0.12 ± 0.08. The total production cross section in units of the point cross section corrected for initial state radiation is R D ∗ = 2.7 ± 0.9 .

e^+ e^-

Abstract Using the CLEO detector, we present a measurement of the mass of the charged charmed strange baryon Ξ + c and its neutral counterpart the Ξ 0 c . The Ξ + c is observed through its decay to Ξ - π + π + , and its mass is measured to be (2467±3±4) MeV. The isospin mass splitting of the Ξ c system is found to be M ( Ξ + c )- M ( Ξ 0 c )=(−5±4±1)MeV.