TESTS OF PERTURBATIVE QCD USING R, $\Gamma _h^Z $ AND EVENT TOPOLOGY MEASUREMENTS IN HADRONIC Z-DECAYS

Abstract

The world data on R and [Formula: see text] is used to derive a value of the QCD scale parameter, free of hadronization and renormalization scale uncertainties, of [Formula: see text]. This value is then used to investigate the convergence of the QCD perturbation expansions for several different jet topology measures, with the choice [Formula: see text] of the renormalization scale. In most cases satisfactory convergence is observed. The overall consistency of all measurements of [Formula: see text] is also discussed. Although [Formula: see text] seems high, present data is consistent (17% C.L.) with a global world average value of [Formula: see text], [Formula: see text].