Accurate Determinations of $\alpha_s$ from Realistic Lattice QCD

TL;DR

This paper presents a precise determination of the QCD coupling constant by combining advanced lattice QCD simulations with experimental hadron mass data, incorporating comprehensive effects and higher-order corrections for improved accuracy.

Contribution

It introduces a novel lattice QCD analysis that includes all three light-quark flavors, third-order perturbation terms, and systematic higher-order estimates, achieving a more accurate alpha_s value.

Findings

Determined alpha_s(M_Z) = 0.1170(12) with high precision.

First lattice analysis to include all three light-quark flavors and third-order perturbation terms.

Achieved systematic estimation of higher-order corrections.

Abstract

We obtain a new value for the QCD coupling constant by combining lattice QCD simulations with experimental data for hadron masses. Our lattice analysis is the first to: 1) include vacuum polarization effects from all three light-quark flavors (using MILC configurations); 2) include third-order terms in perturbation theory; 3) systematically estimate fourth and higher-order terms; 4) use an unambiguous lattice spacing; and 5) use an $\order(a^2)$-accurate QCD action. We use 28~different (but related) short-distance quantities to obtain $\alpha_{\bar{\mathrm{MS}}}^{(5)}(M_Z) = 0.1170(12)$.