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

Abstract Using muon candidates in 133 000 hadronic decays of the Z 0 , 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( Z 0 → b b ) Γ( Z 0 → hadrons ))× Br ( b →μ)=0.0226±0.0007±0.0013 , and also yielded: (Γ( Z 0 → c c ) Γ( Z 0 → 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 Z 0 → b b decays. Without correction for B 0 B 0 mixing, the asymmetry was found to be A b FB = 0.072±0.042±0.010.