Measurement of$b\bar b$ correlations at the CERN$p\bar p$ collider

Abstract

We report on measurements of correlated$b\bar b$ production in$p\bar p$ collisions at$\sqrt s = 630GeV$, using dimuon data to tag both theb and$\bar b$ quarks. Starting from an inclusive dimuon sample we obtain improved cross-sections for single inclusive beauty production and confirm our earlier results on$B^0 - \bar B^0$ mixing. From a study of$b\bar b$ correlations we derive explicit cross-sections for semi-differential$b\bar b$ production. We compare the measured cross-sections and correlations to$\mathcal{O}\left( {\alpha _s^3 } \right)$ QCD predictions and find good quantitative agreement. From the measured angular distributions we establish a size-able contribution from higher order QCD processes with a significance of about seven standard deviations. A large nonperturbative contribution to these higher order corrections is excluded.