Study of heavy flavour production in events with a muon accompanied by jet(s) at the CERN proton-antiproton collider

Abstract

We present a study of heavy flavour (charm and beauty) production using data collected with the UA1 detector at the CERN Proton-Antiproton collider at a centre-of-mass energy of 630 GeV for an integrated luminosity of 556 nb⁻¹. This follows our earlier study ofb $\bar b$ andc $\bar c$ production in dimuon events and the evidence for mixing betweenB ⁰ and$\bar B^0$ states. Properties of an inclusive sample of events containing a muon withp _T >6 GeV/c are compared with QCD predictions for heavy flavour production, using the ISAJET Monte Carlo program. The predicted largep _T muon yield from heavy flavour production and decay agrees with the data to within 30%. For events with a muon ofp _T >10 GeV/c and at least one jet withE _T >10 GeV, we measure the ratio charm/(charm+beauty) to be (24±8±9)%. We also show that the correlations observed between the two heavy quark jets expected by flavour conservation are consistent with the mixture of lowest and higher order QCD processes. We study in detail the topological and kinematic properties of a subsample of events containing a highp _T muon and one or more jets. The good agreement of the theoretical predictions with our data in a region dominated by the production of charm and beauty shows that one of the main background sources to a new heavy quark signature is well understood.