Strong coupling constant from vacuum polarization functions in three-flavor lattice QCD with dynamical overlap fermions

TL;DR

This paper calculates the strong coupling constant lpha_s from lattice QCD vacuum polarization functions with dynamical overlap fermions, providing a precise determination consistent with previous results.

Contribution

It introduces a novel lattice QCD approach using dynamical overlap fermions to accurately extract lpha_s and determine the QCD scale parameter mbda_{\,ar MS}^{(3)}.

Findings

lpha_s^{(5)}(M_Z)=0.1181 with statistical and systematic errors

Determined the QCD scale parameter mbda_{\,ar MS}^{(3)} from lattice data

Results are consistent with previous experimental and theoretical determinations.

Abstract

We determine the strong coupling constant $\alpha_s$ from a lattice calculation of vacuum polarization functions (VPF) in three-flavor QCD with dynamical overlap fermions. Fitting lattice data of VPF to the continuum perturbative formula including the operator product expansion, we extract the QCD scale parameter $\Lambda_{\overline{MS}}^{(3)}$. At the $Z$ boson mass scale, we obtain $\alpha_s^{(5)}(M_Z)=0.1181(3)(^{+14}_{-12})$, where the first error is statistical and the second is our estimate of various systematic uncertainties.