Update: Accurate Determinations of alpha_s from Realistic Lattice QCD

TL;DR

This paper refines the determination of the QCD coupling constant using advanced lattice QCD simulations with multiple lattice spacings and quark mass configurations, reducing errors and improving accuracy.

Contribution

It provides an updated, more precise calculation of alpha_s from lattice QCD, including corrections for lattice spacing and nonperturbative effects, with comprehensive analysis of systematic uncertainties.

Findings

New alpha_V(7.5GeV,nf=3) = 0.2120(28)

Corresponding alpha_msbar(M_Z,n_f=5) = 0.1183(8)

Results agree within one standard deviation with previous measurements.

Abstract

We use lattice QCD simulations, with MILC configurations (including vacuum polarization from u, d, and s quarks), to update our previous determinations of the QCD coupling constant. Our new analysis uses results from 6 different lattice spacings and 12 different combinations of sea-quark masses to significantly reduce our previous errors. We also correct for finite-lattice-spacing errors in the scale setting, and for nonperturbative chiral corrections to the 22 short-distance quantities from which we extract the coupling. Our final result is alpha_V(7.5GeV,nf=3) = 0.2120(28), which is equivalent to alpha_msbar(M_Z,n_f=5)= 0.1183(8). We compare this with our previous result, which differs by one standard deviation.