Determination of the strong coupling constant α_S(m_Z) from measurements of inclusive W± and Z boson production cross sections in proton-proton collisions at √s = 7 and 8 TeV

Twelve measurements of inclusive cross sections of W± and Z boson production, performed in proton-proton collisions at centre-of-mass energies of 7 and 8 TeV, are compared with perturbative quantum chromodynamics calculations at next-to-next- to-leading order (NNLO) accuracy obtained with the CT₁₄, HERAPDF2.0, MMHT₁₄, and NNPDF_(3.0) parton distribution functions (PDFs). Data and theory agree well for all PDF sets, taking into account the experimental and theoretical uncertainties. A novel procedure is employed to extract the strong coupling constant at the Z pole mass from a detailed comparison of all the experimental fiducial cross sections to the corresponding NNLO theoretical predictions, yielding α_S(m_Z) = 0.1163^(+0.0024)_(−0.0031) (CT₁₄), 0.1072^(+0.0043)_(−0.0040) (HERAPDF_(2.0)), 0.1186 ± 0.0025 (MMHT₁₄), and 0.1147 ± 0.0023 (NNPDF_(3.0)). Using the results obtained with the CT₁₄ and MMHT₁₄ PDFs, which yield the most robust and stable α_S(m_Z) extractions, a value α_S(m_Z) = 0.1175^(+0.0025)_(−0.0028) is determined

Determination of the strong coupling constant αS_{S}(mZ_{Z}) from measurements of inclusive W±^{±} and Z boson production cross sections in proton-proton collisions at S\sqrt{S} = 7 and 8 TeV

Twelve measurements of inclusive cross sections of W$^{±}$ and Z boson production, performed in proton-proton collisions at centre-of-mass energies of 7 and 8 TeV, are compared with perturbative quantum chromodynamics calculations at next-to-next- to-leading order (NNLO) accuracy obtained with the CT$_{14}$, HERAPDF$_{2.0}$, MMHT$_{14}$, and NNPDF$_{3.0}$ parton distribution functions (PDFs). Data and theory agree well for all PDF sets, taking into account the experimental and theoretical uncertainties. A novel procedure is employed to extract the strong coupling constant at the Z pole mass from a detailed comparison of all the experimental fiducial cross sections to the corresponding NNLO theoretical predictions, yielding α$_{S}$(m$_{Z}$)=0.1163$_{−0.0031 }^{+0.0024}$ (CT$_{14}$), 0.1072$_{−0.0040 }^{+0.0023}$ (HERAPDF$_{2.0}$), 0.1186 ± 0.0025 (MMHT$_{14}$), and 0.1147 ± 0.0023 (NNPDF$_{3.0}$). Using the results obtained with the CT$_{14}$ and MMHT$_{14}$ PDFs, which yield the most robust and stable α$_{S}$(m$_{Z}$) extractions, a value α$_{S}$(m$_{Z}$)=0.1175$_{−0.0028 }^{+0.0025}$ is determined

αs\alpha_s(2019): Precision measurements of the QCD coupling

This document collects a written summary of all contributions presented at the workshop '$\alpha_s$(2019): Precision measurements of the strong coupling' held at ECT* (Trento) in Feb. 11--15, 2019. The workshop explored in depth the latest developments on the determination of the QCD coupling $\alpha_s$ from the key categories where high precision measurements are available: (i) lattice QCD, (ii) hadronic $\tau$ decays, (iii) deep-inelastic scattering and parton distribution functions, (iv) event shapes, jet cross sections, and other hadronic final-states in $e^+e^-$ collisions, (v) Z boson and W boson hadronic decays, and (vi) hadronic final states in p-p collisions. The status of the current theoretical and experimental uncertainties associated to each extraction method, and future perspectives were thoroughly reviewed. Novel $\alpha_s$ determination approaches were discussed, as well as the combination method used to obtain a world-average value of the QCD coupling at the Z mass pole