Ghost-gluon coupling, power corrections and $\Lambda_{\bar{MS}}$ from twisted-mass lattice QCD at $N_f=2$

TL;DR

This paper presents a non-perturbative lattice QCD calculation of the ghost-gluon coupling constant with $N_f=2$ twisted-mass fermions, revealing non-perturbative power corrections and introducing a new lattice spacing calibration method.

Contribution

It introduces a novel lattice spacing calibration method and analyzes the non-perturbative power corrections in the ghost-gluon coupling from twisted-mass lattice QCD.

Findings

Identification of a non-perturbative OPE contribution dominated by a $raket{A^2}$ condensate.

Extraction of $ abla_{ar{MS}}$ consistent with previous estimates.

Development of a new calibration technique for lattice simulations.

Abstract

A non-perturbative calculation of the ghost-gluon running QCD coupling constant is performed using $N_f=2$ twisted-mass dynamical fermions. The extraction of $\Lambda_{\bar{MS}}$ in the chiral limit reveals the presence of a non-perturbative OPE contribution that is assumed to be dominated by a dimension-two $\VEV{A^2}$ condensate. In this contest a novel method for calibrating the lattice spacing in lattice simulations is presented.