Running Coupling Constant from Position-Space Current-Current Correlation Functions in Three-Flavor Lattice QCD.

Salvatore Calì,Piotr Korcyl,Krzysztof Cichy,Jakob Simeth

doi:10.1103/physrevlett.125.242002

Abstract

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.

Highlights

The Particle Data Group and has competing precision
In this Letter, we provide a determination of the coupling constant in three-flavor quantum chromodynamics (QCD), αMs SðμÞ, for MS renormalization scales μ ∈ ð1; 2Þ GeV
We convert the results perturbatively to the QCD Λ parameter and obtain ΛNf1⁄43 1⁄4 342 Æ 17 MeV, which agrees with the world average published by the Particle Data Group and has competing precision

Summary

Introduction

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. Running Coupling Constant from Position-Space Current-Current Correlation Functions in Three-Flavor Lattice QCD The one-loop-corrected correlators are very close to the four-loop continuum perturbative curve [27], indicating that the remaining discretization effects are small at this lattice spacing.

Results

Conclusion