MEASUREMENTS OF B(0)-(B)OVER-BAR(0) MIXING, GAMMA(Z(0)-]B(B)OVER-BAR)/GAMMA(Z(0)-]HADRONS) AND SEMILEPTONIC BRANCHING RATIOS FOR B-FLAVORED HADRONS IN HADRONIC Z(0) DECAYS

From a sample of about 450 000 hadronic Z0 decays, measurements of the average B0 - B0BAR mixing parameter, chi, the branching fraction of Z0 bosons into hadrons containing bottom quarks, GAMMA(Z0-->bbBAR)/GAMMA(Z0-->hadrons), the average semileptonic branching ratios for such hadrons, B(b-->l) and B(b-->c-->l), and the mean scaled energy of these hadrons, [x(E)], are presented. The measurements were obtained using a simultaneous fit to single-lepton and dilepton events collected with the OPAL detector at LEP, including both electrons and muons. The results are chi = 0.143(+0.022/0.021)+/-0.007 GAMMA(Z0-->bbBAR)/GAMMA(Z0-->hadrons) = 0.222+/-0.011+/-0.007 B(b-->l) = (10.5+/-0.6+/-0.5)% B(b-->c-->l) = (7.7+/-0.4+/-0.7)% [x(E)] = 0.697+/-0.006+/-0.011 where the errors are statistical and systematic, respectively, in each case. The result for B (b-->c-->l) excludes decays of the type b-->cBAR-->l.