Measurement of alpha_s In Hadronic Z-decays Using All-orders Resummed Predictions

Using 109000 hadronic events obtained with the ALEPH detector at LEP at energies close to the Z resonance peak, the strong coupling constant alpha_s ((M(Z))^2) is determined from an analysis of the global event shape variables thrust, heavy jet mass and the differential two-jet rate based on the k(T)-clustering scheme. The analysis uses improved theoretical predictions in which leading and next-to-leading logarithms, resummed to all orders, supplement second order expressions. After combining the results from all variables, alpha_s ((M(Z))^2) is measured to be 0. 12 5 +/- 0.005, where the error is the quadratic sum of experimental and theoretical uncertainties, and is dominated by the latter