EVIDENCE FOR CHAIN-LIKE PRODUCTION OF STRANGE BARYON PAIRS IN JETS

The production dynamics of baryon-antibaryon pairs are investigated using hadronic Z0 decays, recorded with the OPAL detector, which contain at least two identified A baryons. The rapidity difference for AA pairs shows the correlations expected from models with a chain-like production of baryon-antibaryon pairs. If the baryon number of a LAMBDA is compensated by a LAMBDABAR, the LAMBDABAR is found with a probability of 53% in an interval of +/-0.6 around the LAMBDA rapidity. This correlation strength is weaker than predicted by the Herwig Monte Carlo and the Jetset Monte Carlo with a production chain of baryon-antibaryon, and stronger than predicted by the UCLA model. The observed rapidity correlations can be described by the Jetset Monte Carlo with a dominant production chain of baryon-meson-antibaryon, the popcorn mechanism. In addition to the short range correlations, one finds an indication of a correlation of LAMBDALAMBDABAR pairs in opposite hemispheres if both the LAMBDA and the LAMBDABAR have large rapidities. Such long range correlations are expected if the primary quark flavours are compensated in opposite hemispheres and if these quarks are found in energetic baryons. Rates for simultaneous baryon and strangeness number compensation for LAMBDALAMBDABAR, SI-Xi+BAR and XI-LAMBDA+BAR (XI+BAR LAMBDA) are measured and compared with different Monte Carlo models.