A study of two-particle momentum correlations in hadronic Z0 decays

Abstract We report on a measurement of two-particle momentum correlations in hadronicdecays of the Z 0 at LEP. These data are compared with recent analytic QCD calculations based on the summation of leading and next-to-leading logarithms, and with QCD Monte Carlo simulations. We find that the analytic calculations show the same general features as the data, but that the overall level of the correlations is not reproduced, suggesting that higher order or hadronizationeffects are significant. This contrasts with the success of similar QCD calculations in describing single-particle momentum distributions. QCD Monte Carlo models are found to give a reasonable level of correlation, with parton showermodels incorporating string hadronizationgiving the best description of the data.