A STUDY OF B(0)-(B)OVER-BAR(0) MIXING USING SEMILEPTONIC DECAYS OF B-HADRONS PRODUCED FROM Z(0)

The B0-B0BAR mixing was studied by using about '50000 hadronic decays of the Z0, collected with the DELPHI detector at LEP. With 1665 dilepton events, the probability for a b quark to become a bBAR before decaying was found to be chi = 0.121(-0.040)+0.044 +/- 0.017. The semileptonic branching ratio of the b was measured from the dilepton and single lepton events and found to be Br(b --> l) = (10.0 +/- 0.7 +/- 0.7)%.