Determination of the Strong Coupling Constant by the ALPHA Collaboration

Abstract

A high precision determination of the strong coupling constant in the MS-bar scheme at the Z-mass scale, using low energy quantities, namely pion/kaon decay constants and masses, as experimental input is presented. The computation employs two different massless finite volume renormalization schemes to non-perturbatively trace the scale dependence of the respective running couplings from a scale of about 200 MeV to 100 GeV. At the largest energies perturbation theory is reliable. At high energies the Schroedinger-Functional scheme is used, while the running at low and intermediate energies is computed in a novel renormalization scheme based on an improved gradient flow. Large volume Nf=2+1 QCD simulations by CLS are used to set the overall scale. The result is compared to world averages by FLAG and the PDG.

18 pages, 8 figures. Talk presented at the 35th International Symposium on Lattice Field Theory, 18-24 June 2017, Granada, Spain

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Cited by in corpus (3)

• The gradient flow coupling at high-energy and the scale of SU(3) Yang-Mills theory
• Past, present, and future of precision determinations of the QCD coupling from lattice QCD
• The twisted gradient flow coupling at one loop