Determination of the strong coupling from high-energy data

We determine the strong coupling from high-energy data for the Drell–Yan process and top-quark hadro-production collected at the Large Hadron Collider and the Tevatron combined with the world data on deep-inelastic scattering (DIS) and fixed-target Drell–Yan data. The theory description uses results at next-to-next-to-leading order in perturbative QCD in the MS̄ MS ¯ -scheme together with leading order QED evolution. The DIS data are subject to stringent kinematic cuts to suppress the contribution of power corrections. We apply a cut on the hadronic invariant mass squared W² ≥ 12.5~\,GeV² W 2 ≥ 12.5 GeV 2 together with a series of cuts on momentum transfer squared Q² Q 2 . Discarding higher-twist terms we find that the value of strong coupling α ₛ(mZ) α s ( m Z ) preferred by the data stabilizes at large enough cuts on Q² Q 2 , when low- Q² Q 2 DIS data sensitive to power corrections are effectively removed. In particular, we extract the value of α ₛ(mZ,Nf=5)=0.1152 ± 0.0008 α s ( m Z , N f = 5 ) = 0.1152 ± 0.0008 for Nf=5 N f = 5 light flavors with the cut Q²>10~\,GeV² Q 2 > 10 GeV 2 . In the absence of higher-twist terms less tight cuts on Q² Q 2 show a clear deterioration of the fit and lead to rising values of the strong coupling, shifted upwards by about two standard deviations.