First determination of the strong coupling constant using NNLO predictions for hadronic event shapes in e^+e^- annihilations

Abstract

We present the first determination of the strong coupling constant from a fit of next-to-next-to-leading order QCD predictions to event-shape variables, measured in $e^{+}{e}^{-}$ annihilations at LEP. The data have been collected by the ALEPH detector at centre-of-mass energies between 91 and 206 GeV. Compared to results of next-to-leading order fits we observe that the central fit values are lower by about 10%, with considerably reduced scatter among the results obtained with different event-shape variables. The dominant systematic uncertainty from renormalization scale variations is reduced by a factor of two. By combining the results for several event-shape variables and centre-of-mass energies, we find α_s(M_Z^2) = 0.1240+-0.0008(stat)+-0.0010(exp)+-0.0011(had)+-0.0029(theo).

25 pages, LaTeX, extended discussion of hadronization corrections, typos corrected

References in corpus (5)

• A parton shower algorithm based on Catani-Seymour dipole factorisation
• NNLO corrections to event shapes in $e^{+}{e}^{-}$ annihilation
• Second-order QCD corrections to the thrust distribution
• Infrared structure of e+e- --> 3 jets at NNLO
• Extraction of alpha_s from radiative Upsilon(1S) decays

Cited by in corpus (20)

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• Non-Perturbative Contribution to the Thrust Distribution in $e^{+}{e}^{-}$ Annihilation
• Initial-state showering based on colour dipoles connected to incoming parton lines
• Effective Predictions of Event Shapes: Factorized, Resummed, and Gapped Angularity Distributions
• The Realistic Lattice Determination of alpha_s(M_Z) Revisited
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• Matching of Resummed NLLA with Fixed NNLO for Event Shapes
• One-loop electroweak corrections to e+e- into three-jets
• Theoretical Perspectives: XLIII Rencontres de Moriond - QCD
• Event Shape Variables at NLLA+NNLO