A determination ofαs() at LEP using resummed QCD calculations

The strong coupling constant, αs, has been determined in hadronic decays of theZ0 resonance, using measurements of seven observables relating to global event shapes, energy correlations and jet rates. The data have been compared with resummed QCD calculations, which are combined with theO(s2) theory. The seven measurements agree to about 10% and the final results, based on a weighted average, is:$$\alpha _s (M_{Z^0 } ) = 0.120 \pm 0.006,$$ where the error includes both experimental and theoretical uncertainties. This value corresponds to renormalization scale$$\mu = M_{Z^0 } $$ and the error includes the uncertainty in this choice of scale. The present measurement complements previous determinations using theO(s2) QCD matrix elements alone, and yields a compatible result, with comparable errors.