Precise determination of alpha sub(s) from the C-parameter distribution

We present a global fit for alpha sub(s)(m sub(Z)), analyzing the available C-parameter data measured at center-of-mass energies between Q = 35 and 207 GeV. The experimental data is compared to a N super(3)LL' + ((ProQuest: Formulae and/or non-USASCII text omitted)) + [Omega] sub(1) theoretical prediction (up to the missing four-loop cusp anomalous dimension), which includes power corrections coming from a field-theoretical nonperturbative soft function. The dominant hadronic parameter is its first moment [Omega] sub(1), which is defined in a scheme which eliminates the O([Lambda] sub(QCD)) renormalon ambiguity. The resummation region plays a dominant role in the C-parameter spectrum, and in this region a fit for alpha sub(s)(m sub(Z)) and [Omega] sub(1) is sufficient. We find alpha sub(s)(m sub(Z)) = 0.1123 + or - 0.0015 and [Omega] sub(1) = 0.421 + or - 0.063 GeV with chi super(2)/d. o. f. = 0.988 for 404 bins of data. These results agree with the prediction of universality for [Omega] sub(1) between thrust and C-parameter within 1-[sigma].