We report measurements of single-particle inclusive spectra and two-particle correlations in decays of the Υ(1S) resonance and in nonresonant annihilations of electrons and positrons at center-of-mass energy 10.49 GeV, just below BB¯ threshold. These data were obtained using the CLEO detector at the Cornell Electron Storage Ring (CESR) and provide information on the production of π, K, ρ, K*, φ, p, Λ, and Ξ in quark and gluon jets. The average multiplicity of hadrons per event for upsilon decays (compared with continuum annihilations) is 11.4 (10.5) pions, 2.4 (2.2) kaons, 0.6 (0.5) ρ0, 1.2 (0.8) K*, 0.6 (0.4) protons and antiprotons, 0.15 (0.08) φ, 0.19 (0.07) Λ and Λ¯, and 0.016 (0.005) Ξ− and Ξ¯ +. We have also seen evidence for η and f0 production. The most significant differences between upsilon and continuum final states are (1) the inclusive energy spectra fall off more rapidly with increasing particle energy in upsilon decays, (2) the production of heavier particles, especially baryons, is not as strongly suppressed in upsilon decays, and (3) baryon and antibaryon are more likely to be correlated at long range in upsilon decay than in continuum events.
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VALUES AT X = 0.10 ARE ACTUALLY AP RATES DOUBLED.
Using the ARGUS detector at DORIS we have observed the prediction of the charged D ∗ meson in e + e − annihilation at a center of mass energy of 10 GeV. The D ∗ fragmentation function has been measured using the decay channels D ∗+ → D 0 π + and D 0 → K − π + and K − π + π + π − .
RESULTS EXTRAPOLATED TO X>O. SYSTEMATIC ERRORS INCLUDED.
ERRORS ARE STATISTICAL ONLY.
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The production of collinear muon pairs has been studied using the JADE detector at thee+e− storage ring at PETRA. Results for the total cross section and the angular distribution were obtained at centre of mass (cm) energies ranging from 12 to 46 GeV. The data correspond to an integrated luminosity offLdt>90 pb−1, of which 71.2 pb−1 were taken at\(\left\langle {\sqrt s } \right\rangle \)=34.4 GeV and 17 pb−1 at\(\left\langle {\sqrt s } \right\rangle \)=42.4 GeV. The results are compared to electroweak theories, in particular the “Standard Model”.
QED comparison is to point like cross section.
Angular distributions - data requested from authors.
Forward-backward asymmetry calculated from a fit to the angular distribution of the form 1: + cos(theta)**2 + Bcos(theta).. Asymmetries quoted here are extrapolated to full solid angle. The asymmetry at sqrt(s) = 34.4 is -11.10 +- 1.75 +- 1.0 pct if the end-cap points are included.
The production of Λ hyperons in e+e− annihilation has been measured as a function of their total momenta, transverse momenta, and the event thrust. The total production rate is 0.213±0.012±0.018 Λ or Λ¯ per hadronic event. The observation of correlations in rapidity and angles for events with two detected Λ decays supports fragmentation models with local baryon-number compensation.
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The production of electrons by bottom and charm hadrons has been studied in e + e − annihilation at 34.6 GeV center of mass energy. It is observed that the b quark fragmentation function is peaked at large values of the scaling variable z with 〈 z b 〉 = 0.84 +0.15 + 0.15 −0.10 − 0.11 . For c quarks 〈 z c 〉 = 0.57 +0.10 + 0.05 −0.09 − 0.06 is observed. A forward-backward charge asymmetry of A = −0.25 ± 0.22 was measured in b production.
THE VALUE OF ASYMMETRY WAS DETERMINED USING A SAMPLE OF PROMPT ELECTRONS.
THE VALUE OF ASYMMETRY WAS DETERMINED USING A SAMPLE OF PROMPT ELECTRONS.
UPPER LIMITS FOR DEL(1232)++ PRODUCTION.
UPPER LIMITS FOR SIG(1385)+- PRODUCTION.
The forward-backward charge asymmetry for the process e + e − → b b ̄ → μ ± + hadrons has been measured using the JADE detector at PETRA. An asymmetry of (−22.8 ± 6.0 ± 2.5)% was observed at an average center of mass energy of 34.6 GeV. For comparison, an asymmetry of −25.2% is expected on the basis of the standard Glashow-Salam-Weinberg model.
THE VALUE OF CONST HAVE BEEN RESCALED TO DEFINITION I3(Q) = 1/2 BY OPY.
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The energy-energy correlation cross section for hadrons produced in electron-positron annihilation at a center-of-mass energy of 29 GeV has been measured with the MAC detector at SLAC. The result is corrected for the effects of detector resolution, acceptance, and initial-state radiation. The correlation is measured in two independent ways on the same data sample: the energy weights and angles are obtained either from the energy flow in the finely segmented total absorption calorimeters or from the momenta of charged tracks in the central drift chamber. This procedure helps reduce systematic errors by cross-checking the effects of the detector on the measurement, particularly important because the corrections depend on complex Monte Carlo simulations. The results are compared with the predictions of Monte Carlo models of complete second-order perturbative quantum chromodynamics and fragmentation, with the following conclusions: (1) fitting the asymmetry for large correlation angles gives values for αS of 0.120±0.006 in perturbation theory, 0.185±0.013 in the Lund string model, and values which vary from 0.105 to 0.140 (±0.01) in the incoherent jet models, depending on the gluon fragmentation scheme and the algorithm used for momentum conservation; and (2) the string fragmentation model provides a satisfactory description of the measured energy-energy correlation cross section, whereas incoherent jet formation does not.
VALUES FOR THE ASSYMETRY ARE GIVEN ALSO.
Using the ARGUS detector at DORIS we have obtained evidence for a resonance which decays into an F meson and a photon. The observed mass is 2109 ± 9 ± 7 MeV, which is 144 ± 9 ± 7 MeV greater than the F meson mass. Its properties are consistent with those of the F ∗ meson with J P = 1 − .
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