Calì Salvatore, Cichy Krzysztof, Korcyl Piotr, Simeth Jakob
Institute of Theoretical Physics, Jagiellonian University, ulica Łojasiewicza 11, 30-348 Kraków, Poland.
Faculty of Physics, Adam Mickiewicz University, ulica Uniwersytetu Poznańskiego 2, 61-614 Poznań, Poland.
Phys Rev Lett. 2020 Dec 11;125(24):242002. doi: 10.1103/PhysRevLett.125.242002.
In this Letter, we provide a determination of the coupling constant in three-flavor quantum chromodynamics (QCD), α_{s}^{MS[over ¯]}(μ), for MS[over ¯] renormalization scales μ∈(1,2) GeV. The computation uses gauge field configuration ensembles with O(a)-improved Wilson-clover fermions generated by the Coordinated Lattice Simulations (CLS) consortium. Our approach is based on current-current correlation functions and has never been applied before in this context. We convert the results perturbatively to the QCD Λ parameter and obtain Λ_{MS[over ¯]}^{N_{f}=3}=342±17 MeV, which agrees with the world average published by the Particle Data Group and has competing precision. The latter was made possible by a unique combination of state-of-the-art CLS ensembles with very fine lattice spacings, further reduction of discretization effects from a dedicated numerical stochastic perturbation theory simulation, combining data from vector and axial-vector channels, and matching to high-order perturbation theory.
在本信函中，我们给出了三味量子色动力学（QCD）中耦合常数α_s^{MS[overline]}(μ)在MS[overline]重整化标度μ∈(1,2) GeV下的确定值。该计算使用了由协调晶格模拟（CLS）联盟生成的具有O(a)改进威尔逊-克洛弗费米子的规范场构型系综。我们的方法基于流-流关联函数，此前从未在此背景下应用过。我们将结果微扰地转换为QCD Λ参数，并得到Λ_{MS[overline]}^{N_f = 3}=342±17 MeV，这与粒子数据组公布的世界平均值相符且具有相当的精度。后者之所以能够实现，是因为最先进的CLS系综与非常精细的晶格间距的独特组合、通过专门的数值随机微扰理论模拟进一步降低离散化效应、结合矢量和轴矢量通道的数据以及与高阶微扰理论相匹配。
