BUSKULIC, D (reprint author), CNRS, IN2P3, PHYS PARTICULES LAB, F-74019 ANNECY LE VIEUX, FRANCE.
The branching fraction of Z --> bbBAR relative to all hadronic decays of the Z has been measured using event shape variables to preferentially select Z --> bbBAR events. The method chosen applies a combination of shape discriminators and the selection of high transverse momentum leptons to event hemispheres. From a sample of 440000 hadronic Z decays collected with the ALEPH detector at LEP, the ratio GAMMA(bbBAR)/GAMMA(had) = 0.228+/-0.005(stat.)+/-0.005(syst.) is measured.