Cross sections are presented for the inclusive production of Λ hyperons in electron-positron annihilations at s=29 GeV based on the full 291-pb−1 sample of data taken in the High Resolution Spectrometer experiment at the SLAC e+e− storage ring PEP. These results, and the associated correlation analyses, are consistent with the Lund model predictions with the strange diquark suppression ratio δ fixed at 0.59±0.10±0.18, as compared to the standard Lund value of 0.32. The Λ multiplicity has been found to be 0.182±0.020 per event. The opposite-strangeness multiplicity 〈nΛΛ¯〉 has been measured to be 0.046±0.020, whereas the like-strangeness multiplicity 〈nΛΛ+Λ¯Λ¯〉 is 0.009±0.028. A strong correlation is found between Λ's and Λ¯'s; when one is found in an event, the other is found in the same event with a probability that exceeds 50%.
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Extrapolate to full z interval using Lund fit.
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Data from the High Resolution Spectrometer at the SLAC storage ring PEP have been used to study the inclusive production of baryons and mesons. Time-of-flight measurements are used to identify the charged hadrons. Neutral hadrons are identified from effective-mass peaks associated with their decay into two charged particles. Cross sections and other inclusive production characteristics are presented for π±, K±, and K0 (K¯0) mesons, and for the baryons (antibaryons) p (p¯) and Λ (Λ¯). The ratio of the inclusive cross section to the point cross section for the K0 and K¯0 mesons is R(K0,K¯0)=6.15±0.13±0.25, and for Λ and Λ¯, R(Λ,Λ¯)=0.846±0.036±0.085. The neutral-hadron differential cross sections are compared with the predictions of the Lund string model.
Charged particle fractions. Errors contain systematic uncertainties.
Charged particle invariant cross sections. Errors contain systematic uncertainties.
Charged particle invariant cross sections. Errors contain systematic uncertainties.
Total and differential K0 corss sections are presented from e+e− collisions at s=29 GeV in the High Resolution Spectrometer detector. K0 and charged-particle distributions are compared in a study of the hadronization of quarks of known flavor. Ecents of the reaction e+e−→cc¯ are tagged by identifying D*'s while uu¯, dd¯, or ss¯ events are tagged through the identification of a charged particle with fractional momentum near 1. Parton-shower models with cluster and string fragmentation are compared with these data. Also, certain particle scaling tests are performed using the quark-flavor tags. In addition, K0 production in two- and three-jet events is compared to these models.
Corrected Cross Sections (Lund MC used to extrapolate).
R value for K0 production.
K0 differential cross section as function of the fractional energy.
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