No Arabic abstract
Bose-Einstein correlations of pairs of identical charged pions produced in hadronic Z decays are analyzed in terms of various parametrizations. A good description is achieved using a Levy stable distribution in conjunction with a model where a particles momentum is correlated with its space-time point of production, the taumodel. Using this description and the measured rapidity and transverse momentum distributions, the space-time evolution of particle emission in two-jet events is reconstructed. However, the elongation of the particle emission region previously observed is not accommodated in the taumodel, and this is investigated using an adhoc/ modification.
Bose-Einstein correlations of pairs of identical charged pions produced in hadronic Z decays are analyzed in terms of various parametrizations. A good description is achieved using a Levy stable distribution in conjunction with a hadronization model having highly correlated configuration and momentum space, the tau-model. Using these results, the source function is reconstructed.
Bose-Einstein correlations in pairs of identical particles were analyzed in e+ e- multihadron annihilations at ~91.2 GeV at LEP. The first studies involved identical charged pions and the emitting source size was determined. Then the study of charged kaons suggested that the radius depends on the mass of the emitted particles. Subsequenty the dependence of the source radius on the event multiplicity was analyzed. The study of the correlations in neutral pions and neutral kaons extended these concepts to neutral particles. The shape of the source was analyzed in 3 dimensions and was found not to be spherically symmetric. In recent studies at LEP the correlations were analyzed in intervals of the average pair transverse momentum and of the pair rapidity to study the correlations between the pion production points and their momenta (position-momentum correlations). The latest e+ e- data are consistent with an expanding source.
Bose-Einstein correlations of pairs of identical charged pions produced in hadronic Z decays and in 7 TeV pp minimum bias interactions are investigated within the framework of the tau-model.
An overview of measurements of Bose-Einstein correlations in W-pair events at LEP is given. The results presented are based on data collected at centre-of-mass energies between 172 and 202GeV. The review concentrates on the search for Bose-Einstein correlations between pions from different Ws in e+e- -> W+W- -> qqbarqqbar events. No agreement is reached in the results of the four experiments.
The mean charge multiplicity in hadronic three-jet Z decays has been measured with the DELPHI detector as a function of the event topology and compared with recent theoretical calculations. The QCD colour factor ratio C_A/C_F was determined, and the gluon contribution to this multiplicity was extracted giving a measurement of the mean charge multiplicity of a two-gluon colour-singlet system as a function of the effective c.m. energy covering the range from 16 to 52 GeV.