Determination of α S using OPAL hadronic event shapes at $\sqrt{s} = 91\mbox{--}209~\mathrm{GeV}$ and resummed NNLO calculations

Abstract

Hadronic event shape distributions from e + e -annihilation measured by the OPAL experiment at centre-ofmass energies between 91 GeV and 209 GeV are used to determine the strong coupling S . The results are based on QCD predictions complete to the next-to-next-to-leading order (NNLO), and on NNLO calculations matched to the resummed next-to-leading-log-approximation terms (NNLO+ NLLA). The combined NNLO result from all variables and centre-of-mass energies is S (m Z 0 ) = 0.1201 0.0008(stat.) 0.0013(exp.) 0.0010(had.) 0.0024(theo.) while the combined NNLO + NLLA result is S (m Z 0 ) = 0.1189 0.0008(stat.) 0.0016(exp.) 0.0010(had.) 0.0036(theo.)