The multiplicities per event of π ± and K ± are measured separately for e + e - annihilation into c c , b b , and light quark pairs at E cm=29 GeV. The K ± multiplicity is higher for heavy quark events than for light quark events. The π ± multiplicity and the π ± scaled differential cross section at low x = E beam/ E beam are found to be higher for b b events than for other events.
Numerical values requested from authors. Data given separately for (b bbar), (c cbar) and light quark jets.
Measured multiplicities for (b bbar) jets.
Measured multiplicities for (c cbar) jets.
The n̄p total and annihilation cross section have been measured from near N̄N threshold (1880 MeV) to 1940 MeV with RMS resolution ranging from 0.08 MeV (1880 MeV) to 6.7 MeV (1940 MeV). No significant narrow meson structures were seen, with 90% CL upper limits of 40–180 mb-MeV on σΓ for states with width less than our resolution. Combined with increasing unitarity bounds on σ as one approaches threshold, these limits confine widths of possible predicted states below 1900 MeV to less than ∼ 1 MeV.
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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.
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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 analysing powers in free →n p forward elastic scattering have been measured for incident neutron energies of 633, 784, 834, 934 and 985 MeV, and for momentum transfer 0.01 < ‖ t ‖ < 0.10 ( GeV / c ) 2 . The experiment used a recoil detector ionisation chamber which served at the same time as a gas target, and scintillation counters to measure the asymmetry of the scattered neutrons.
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Results are presented on inclusive production of ∑+(1385) and ∑−(1385) inK−p interactions at 110 GeV/c. The inclusive and topological cross sections have been estimated and compared with published results at lower energies. The inclusive cross section of ∑+(1385) seems to decrease with c.m. energy, while that of the ∑−(1385) is nearly constant. The mean charged multiplicity associate to Σ(1385) increases with c.m. energy. The ∑+(1385) is produced both in the target fragmentation region and in the central region where ∑−(1385) is predominantly produced in the central region. Approximately 16% of the Λ's stem from the decay of ∑±(1385) and the kinematic distributions of these Λ's are not very different from the inclusive Λ's.
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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.
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Accurate measurements of the left-right asymmetry in π−p→γn at pπ=427−625 MeV/c with a transversely polarized target are reported. Results are compared with the predictions from the Arai and Fujii single-pion photoproduction partial-wave analysis and with data on the inverse process measured with a deuterium target. The agreement is poor, casting doubt on the correctness of the value for the radiative-decay amplitude of the neutral Roper resonance now in use.
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We present data on inclusive production ofK+ andKS0 mesons in a 70 GeV/cK+p experiment performed in BEBC filled withH2. Cross sections and inclusive Feynman-x distributions for identifiedK+'s andKS0's are presented. The spectra of “prompt” non-diffractiveKS0 are determined by subtraction of the decay products of prominent resonances and diffractive contributions. These data, contrary to the overall inclusive spectra, allow to differentiate between some fragmentation models for soft hadron-hadron interactions.
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