A study of heavy flavour production using muons in hadronic Z0 decays

Using muon candidates in 133 000 hadronic decays of the Z0, recorded by the OPAL detector at LEP, we have measured the fraction of events containing semi-leptonic decays of b flavoured hadrons. An analysis based on fitting the shape of the momentum and transverse momentum distributions of the muon candidates gave the result: (Γ(Z0→bb)Γ(Z0→hadrons))×Br(b→μ)=0.0226±0.0007±0.0013, and also yielded: (Γ(Z0→cc)Γ(Z0→hadrons))×Br(c→μ)=0.0176±0.0025±0.0042. Using the charge of the muon and the angle of the event thrust axis with respect to the electron beam, in a b-enriched event sample, we measured the forward-backward asymmetry for Z0 → bb decays. Without correction for B0B0 mixing, the asymmetry was found to be AbFB = 0.072±0.042±0.010.