The correlated production of Lambda and Lambdabar baryons has been studied using 4.3 million multihadronic Zo decays recorded with the OPAL detector at LEP. Di-lambda pairs were investigated in the full data sample and for the first time also in 2-jet and 3-jet events selected with the k_t algorithm. The distributions of rapidity differences from correlated Lambda-Lambdabar pairs exhibit short-range, local correlations and prove to be a sensitive tool to test models, particularly for 2-jet events. The JETSET model describes the data best but some extra parameter tuning is needed to improve agreement with the experimental results in the rates and the rapidity spectra simultaneously. The recently developed modification of JETSET, the MOdified Popcorn Scenarium (MOPS), and also HERWIG do not give satisfactory results. This study of di-lambda production in 2- and 3-jet events supports the short-range compensation of quantum numbers.
Average multipicity of LAMBDA pairs in hadronic events.
Average multipicity of LAMBDA pairs in 2-Jet events.
Average multipicity of LAMBDA pairs in 3-Jet events.
Experimental results on the K L 0 p → K S 0 p reaction at 11 laboratory momenta between 300 and 800 MeV/ c are presented. The data are used to discriminate among the various sets of phase shifts for K + N scattering in the I = 0 state.
STATISTICAL ERRORS ONLY. CROSS SECTIONS ARE NORMALIZED RELATIVE TO THE PI+ LAMBDA EVENTS - SEE THE RECORD OF L. BERTANZA ET AL., NP B110, 1 (1976).
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