Inclusive cross sections of η production by e + e - annihilation for c.m. energies between 4.0 and 5.0 GeV are presented. The η production is shown to be correlated with the production of a weakly decaying particle, indicating that its main source is F production. At the 4.42 GeV resonance it is correlated with a low energy photon, suggesting F F ∗ or F ∗ F ∗ production. A mass determination of the F is made at 4.42 GeV using the F → ηπ decay channel.
NUMERICAL VALUES MEASURED FROM GRAPH IN PREPRINT. A CHARM MODEL (METHOD 2) GAVE CONSISTENT RESULTS FOR BACKGROUND SEPARATION.
The production of photons ine+e−→γ+hadrons is investigated at three centre of mass energies around 14, 22 and 34 GeV. On average, photons carry 25% of the total available energy, with a multiplicity similar to the charged multiplicity. The inclusive photon spectra are found to scale with the centre of mass energy as a function of the Feynman variablex. π0 and η mesons are reconstructed from their decay photons. The slopes of the spectra are similar to that for charged pions and approximate scaling is observed for π0 production. The mean π0 and η multiplicities are given. The observed photon yield can be fully accounted for by hadron decays and initial state radiation. However, up to one extra photon per event from other sources cannot be excluded.
No description provided.
No description provided.
No description provided.
η production has been investigated by the Mark II collaboration at the SLAC e+e− storage ring PEP. η particles are reconstructed by their γγ decay mode. The η fragmentation function has been measured and found to be in good agreement with the Lund-model prediction. η′ production has been measured for the first time in high-energy e+e− annihilation. There is evidence at the 3σ level for Ds± decay into ηπ± and η′π±.
Numerical values supplied by G.Wormser.
Z = 0.0 point extrapolated using LUND fragmentation model.
Z = 0.0 point extrapolated using LUND fragmentation model.
None
SEARCH FOR F MESON IN THE INCLUSIVE ETA SPECTRUM.
UPPER LIMIT (95 PCT CL) OF F PRODUCTION FROM THE INCLUSIVE GAMMA SPECTRUM. MASS OF F MESON TAKEN AS 2030 MEV.
UPPER LIMIT (95 PCT CL) OF F PRODUCTION FROM THE INCLUSIVE GAMMA SPECTRUM. MASS OF F MESON TAKEN AS 2030 MEV.
Data from e + e − annihilations at 29 GeV have been used to measure the production cross section and fragmentation function of η mesons. The signal is observed in the η → γγ decay channel. The fragmentation for p η >1.5 GeV/ c agrees well with the prediction of the Lund model, whereas the prediction of the Webber model lies above the data. The mean multiplicity is measured to be 〈 n η 〉=0.58±0.10 η mesons per hadronic event, of which 0.51 represents the direct production of η and η ′ mesons in the fragmentation chain.
Statistical errors only.
Extrapolated to full z range using LUND model.
The decays η → γγ and η ′ → ηπ + π − have been observed in hadronic decays of the Z produced at LEP. The fragmentation functions of both the η and η ′ have been measured. The measured multiplicities for x > 0.1 are 0.298±0.023±0.021 and 0.068±0.016 for η and η ′ respectively. While the fragmentation function for the η is fairly well described by the JETSET Monte Carlo, it is found that the production rate of the η ′ is a factor of four less than the corresponding prediction.
No description provided.
Additional 7 pct systematic error.
Additional 23 pct systematic error.
We present a study of the inclusive η production based on 300 000 hadronic Z 0 decays. The measured inclusive momentum distribution can be reproduced by parton shower Monte Carlo programs and also by an analytical QCD calculation. Comparing our results with low energy e + e − data, we find that QCD describes both the shape and the energy evolution of the η spectrum. The comparison of η production rates in quark- and gluon-enriched jet samples does not show statistically significant evidence for more abundant production of η mesons in gluon fragmentation.
Differential cross section for inclusive eta production, normalized to the total hadronic cross section.
Differential cross section for inclusive eta production, normalized to the total hadronic cross section.
The inclusive production of η mesons at CM energies around 34 GeV has been studied for e + e − annihilation into hadrons. The average number of η-mesons per event is found to be 0.72 ± 0.10 (stat.) ± 0.18 (syst.). The abundance of η's is studied as a function of event shape parameters and it is compared to the corresponding π 0 rates.
No description provided.
DATA REQUESTED FROM AUTHORS.
We have measured the inclusive production of γ, π0 and η ine+e− annihilation at the center of mass energy of 35 GeV. The differential cross sections, extended to the kinematical limit and measured with high accuracy, are found to be in good agreement with previously reported results. Using the measured spectra we determine the average multiplicity for each of these particle species.
No description provided.
Statistical errors only.
Statistical errors only.
We present a study of inclusive π0 and ŋ production ine+e− annihilation at
Particle multiplicities in the continuum.
Particle multiplicities in the UPSILON (1S).
Inclusive pi0 spectra in the continuum.
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