Studies on Bose-Einstein correlations in W-pair decays

Bose-Einstein correlations in W-pair decays are studied using data collected by the ALEPH detector at centre-of-mass energies up to 209 GeV. The analysis presented is based on the comparison of selected WW-->qqqq events to ``mixed'' events constructed from the hadronic parts of selected WW-->qqlnu events. Data are in good agreement with the hypothesis where Bose-Einstein correlations are present only for pions coming from the same W, while the JETSET model with Bose-Einstein correlations between pions from different Ws is disfavoured.