Precision determination of the strong coupling constant within a global PDF analysis: NNPDF Collaboration

We present a determination of the strong coupling constant [Formula: see text] based on the NNPDF3.1 determination of parton distributions, which for the first time includes constraints from jet production, top-quark pair differential distributions, and the Z [Formula: see text] distributions using exact NNLO theory. Our result is based on a novel extension of the NNPDF methodology – the correlated replica method – which allows for a simultaneous determination of [Formula: see text] and the PDFs with all correlations between them fully taken into account. We study in detail all relevant sources of experimental, methodological and theoretical uncertainty. At NNLO we find [Formula: see text] , showing that methodological uncertainties are negligible. We conservatively estimate the theoretical uncertainty due to missing higher order QCD corrections (N[Formula: see text] LO and beyond) from half the shift between the NLO and NNLO [Formula: see text] values, finding [Formula: see text] .