The inclusive production of η mesons has been studied using 1.6 million hadronic Z decays collected with the L3 detector. The η multiplicity per event, the multiplicity for two-jet and three-jet events separately, and the multiplicity in each jet have been measured and compared with the predictions of different Monte Carlo programs. The momentum spectra of η in each jet have also been measured. We observe that the measured η momentum spectrum in quark-enriched jets agrees well with the Monte Carlo prediction while in gluon-enriched jets it is harder than that predicted by the Monte Carlo models.
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We present a study of the inclusive production of π 0 , η, K s 0 and Λ based on 929,000 hadronic Z decays recorded with the L3 detector at LEP. The measured inclusive momentum distributions have been compared with predictions from parton shower models as well as an analytical Quantum Chromodynamics calculation. Comparing to low energy e + e - data, we find that QCD describes the energy evolution of the hadron spectrum.
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We present a study of the inclusive production of neutral pions and charged particles from 112 000 hadronic Z 0 decays. The measured inclusive momentum distributions can be reproduced by parton shower Monte Carlo programs and also by an analytical QCD calculation. Comparing our results to e + e − data between √ s = 9 and 91 GeV, we findfind that the evolution of the spectra with center of mass energy is consistent with the QCD predictions.
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Error is dominated by systematic uncertainties.
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Inclusive production cross sections for photons and π0's ine+e− annihilation at a center of mass energy of 29 GeV have been measured. The π0 production spectrum agrees with a corresponding measurement for π±. The ratio of the π0 inclusive rate to the average for π± is 0.92±0.14. The fractions of the total energy carried by photons and π0's are 0.244±0.016 and 0.217±0.033, respectively. The fraction of total energy carried by all stable hadrons, prompt leptons and photons is determined to be 0.938±0.045, leaving 0.062±0.045 for neutrinos.
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The inclusive γ and π0 momentum spectra from ψ(3100) decay have been measured in e+e− annihilation at SPEAR. When the γ spectrum is compared with that expected from π0 decay, an excess of high-momentum γ's is observed. This excess is compared with that predicted by quantum chromodynamics for the decay of the ψ into a γ and two gluons.
THE STATISTICAL AND SYSTEMATIC ERRORS ARE GIVEN SEPARATELY AS WELL AS COMBINED IN QUADRATURE FOR THE QUOTED TOTAL ERROR.
THE STATISTICAL AND SYSTEMATIC ERRORS ARE GIVEN SEPARATELY AS WELL AS COMBINED IN QUADRATURE FOR THE QUOTED TOTAL ERROR. SYSTEMATIC ERROR IS 17 PCT.
QUOTED ERRORS ARE STATISTICAL. SYSTEMATIC ERROR IS 20 PCT. ONLY HALF THE SUM OF THE PI+ AND PI- CROSS SECTIONS IS PLOTTED IN THE FIGURE IN THE JOURNAL.
We have measured inclusive γ and π0 production in multiprong events produced by e+e− annihilation in the center-of-mass energy range 4.9 to 7.4 GeV. We find the π0 inclusive cross section to be consistent in shape and normalization with half the charged-π cross section between x=0.15 and 0.60, with an integrated inclusive cross-section ratio of σ(π0)|σ(π+)+σ(π−)|=0.47±0.10.
NUMERICAL VALUES OF DATA FROM THIS EXPERIMENT HAVE NOT BEEN KEPT (M. L. PERL, PRIV COMM, 3 MAY 1979).
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