Bose-Einstein correlations and color reconnection in hadronic W

Abstract

We report on studies of Bose-Einstein correlations and color reconnection in hadronic W pair production at LEP. Bose-Einstein correlations between identical particles from the decay of different W's are studied by comparing the particle correlation in hadronic W pair decays to those in events which are constructed from the combination of the hadronic parts of two events where one of the Ws decays leptonicaly. The LEP combined result of the strength of the effect is consistent with zero and can be used to limit the systematic uncertainty due to Bose-Einstein correlations on the W mass measurements. Color reconnection is expected to affect the production of particles in hadronic decays of W pairs. Measurements of inclusive charged particle multiplicities, and of their angular distribution with respect to the four jet axes of the events, are used to test models of color reconnection. The results are both consistent with models without color reconnection and models with moderate color reconnection. They can be used to exclude more extreme models of color reconnection and thereby limit the uncertainty due to color reconnection on the W mass measurement.