New data are presented on charged particle multiplicity distributions for non single-diffractive events produced at CM energies s = 200 and 900 GeV . The data were obtained at the CERN antiproton-proton collider operated in a new pulsed mode. The multiplicity distributions are very well described by a negative binomial distribution. The highest energy data show no sign of approaching scaling, confirming our earlier results on the breaking of KNO scaling. The energy variation of the average charged multiplicity can be fitted to a quadratic in ln s or a s 0.13 dependence.
Figure gives uncorrected multiplicity distributions. Here we give the corrected distributions. Data supplied by D. Ward.
Results for multiplicity moments based on negative binomial fit to corrected data. Errors reflect both statistical and systematic effects. Results from earlier data at 546 Gev cm energy are also given.
C moments for corrected data where CQ=<N**Q>/<N>**Q.
We have observed decays of the ϒ(1S) into hadronic final states containing high-energy photons. These are interpreted as coming from the decay ϒ(1S)→γ+gluon+gluon. We compare the shape of the observed photon energy spectrum with several theoretical predictions and deduce the value of the strong-coupling constant αs and the QCD scale parameter ΛMS― (MS― denotes the modified minimal-subtraction scheme) associated with each prediction.
DATA TAKEN ON THE PEAK OF THE UPSI(9460).
DATA TAKEN ON THE PEAK OF THE UPSI(9460).
A new technique is applied to data collected at the ψ(3770) resonance to derive charmed-D-meson branching fractions without relying on the measurement of D-production cross sections. Measurements are presented for three decay modes of the D0 (K−π+, D−π−π+π+, and K−π+π0 and four decay modes of the D+ (K−π+π+,K−π+π+π0,KS0π+, and KS0π+π0). The resulting branching fractions are significantly larger than previous measurements.
No description provided.
No description provided.
The polarization of Λ0 hyperons in inclusive production by 12-GeV protons on nuclei has been measured for beryllium, copper, and tungsten targets. Data are obtained at five production angles, 3.5°, 5.0°, 6.5°, 8.0°, and 9.5°, covering the kinematic range 0.26≤xF≤0.77 and 0.4≤pT≤1.5 GeV/c. The dependence of the polarization on target nuclei is investigated by statistical analyses of the data. The polarization at fixed pT increases roughly linearly with xF. The present results are compared with other work at higher energies in terms of the A dependence and the (xF,pT) dependence.
No description provided.
No description provided.
No description provided.
The first data on the production of D ∗ (2010) are presented as observed in π − -proton interactions at √ s = 27 GeV . It is found that D ∗ (2010) dominates the total charm D-meson production, without a significant non-central component.
No description provided.
No description provided.
No description provided.
The first results on inclusive photoproduction of π 0 at transverse momenta up to 4 GeV/ c , using incident γ energies between 50 and 150 GeV are presented. A comparison is made with inclusive π 0 production obtained, in the same experiment, with incident π − . Using the π − data to parametrize the hadronic behaviour of the photon, significant differences are observed in quantitative agreement with QCD Compton scattering and corrections thereof.
FC,IC,BC REFER TO FORWARD,INTERMEDIATE AND BACKWARD CALORIMETERS.
FC,IC,BC REFER TO FORWARD,INTERMEDIATE AND BACKWARD CALORIMETERS.
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 .
KNO charged multiplicity distributions for the Inclusive Data Sample. The numerical values are calculated from the multiplicity distributions given in Derrick et al., PR D34,3304.
Folded rapidity distribution measured along the thrust axis of the event. Errors are dominated by systematics. All charged particles are assigned the pion mass.
KNO charged multiplicity distribution for the Two Jet Data Sample. The numerical values are calculated from the multiplicity distributions given in Derrick et al., PR D34,3304.
None
No description provided.
No description provided.
No description provided.
Interaction cross sections (σI) for all known Li isotopes (Li6-Li11) and Be7, Be9, and Be10 on targets Be, C, and Al have been measured at 790 MeV/nucleon. Root mean square radii of these isotopes as well as He isotopes have been deduced from the σI by a Glauber-type calculation. Appreciable differences of radii among isobars (He6-Li6, He8-Li8, and Li9-Be9) have been observed for the first time. The nucleus Li11 showed a remarkably large radius suggesting a large deformation or a long tail in the matter distribution.
No description provided.
This paper presents measurements of the inclusive production cross sections of Λ baryons in e+e− annihilations at s=29 GeV. The data sample corresponds to an integrated luminosity of 256 pb−1 collected with the High-Resolution Spectrometer at the SLAC storage ring PEP. Comparisons are made to the predictions of the Lund model. The data are well described with use of a strange-diquark suppression parameter, (usud)(sd), of 0.89 ± 0.10−0.16+0.56, and the measured Λc→Λ+X branching ratio of (23 ± 10)%.
No description provided.
Rapidity relative to thrust axis.
Corrected for unobserved moment regions.
Forum