The strong running coupling at $\tau$ and $Z_0$ mass scales from lattice QCD

TL;DR

This paper presents a lattice QCD calculation of the strong coupling constant at tau and Z boson mass scales, achieving results consistent with experimental data by including dynamical charm quarks for improved accuracy.

Contribution

First lattice QCD computation of the running strong coupling using ghost-gluon coupling in the MOM Taylor scheme with $u,d,s,c$ quarks in the sea.

Findings

Estimates of $ar{ m a}_s(m_ au^2)$ and $ar{ m a}_s(m_Z^2)$ agree with experimental values.

Including dynamical charm quarks improves the reliability of the running.

Provides a non-perturbative determination of the strong coupling at relevant energy scales.

Abstract

This letter reports on the first computation, from data obtained in lattice QCD with $u,d,s$ and $c$ quarks in the sea, of the running strong coupling via the ghost-gluon coupling renormalized in the MOM Taylor scheme. We provide with estimates of $\ams(m_\tau^2)$ and $\ams(m_Z^2)$ in very good agreement with experimental results. Including a dynamical c quark makes safer the needed running of $\ams$.