Bose-Einstein correlations in e+e- → W+W- at 172 and 183 GeV

Bose-Einstein correlations between like-charge pions are studied in hadronic final states produced by e(+)e(-) annihilations at center-of-mass energies of 172 and 183 GeV. Three event samples are studied, each dominated by one of the processes W+W- --> q (q) over bar l (v) over bar i, W+W- --> q (q) over bar q (q) over bar, or (Z(0)/gamma)* --> q (q) over bar. After demonstrating the existence of Bose-Einstein correlations in W decays, an attempt is made to determine Bose-Einstein correlations for pions originating front the same W boson and from different W bosons, as well as for pions from (Z(0)/gamma)* --> q (q) over bar events. The following results are obtained for the individual chaoticity parameters lambda, assuming a common source radius R:lambda(same) = 0.63+/- 0.19 +/- 0.14lambda(diff) = 0.22 +/- 0.53 +/- 0.14lambda(Z*) = 0.47 +/- 0.11 +/- 0.08R = 0.92 =/- 0.09 +/- 0.09 fmIn each case, the first error is statistical and the second is sq systematic. At the current level of statistical precision it is not established whether Bose-Einstein correlations, between pions from different W bosons exist or not.