Non-perturbative O(a) improvement of lattice QCD

TL;DR

This paper non-perturbatively computes the coefficients for O(a) improvement in lattice QCD using a finite-size Schrödinger functional method, enhancing the precision of lattice simulations.

Contribution

It provides the first non-perturbative determination of improvement coefficients for lattice QCD in the quenched approximation across a range of gauge couplings.

Findings

Coefficients for O(a) improvement are computed non-perturbatively.

Critical hopping parameter κ_c is determined at all couplings.

Method employs Schrödinger functional in finite volume at near-zero quark mass.

Abstract

The coefficients multiplying the counterterms required for O($a$) improvement of the action and the isovector axial current in lattice QCD are computed non-perturbatively, in the quenched approximation and for bare gauge couplings $g_0$ in the range $0 \leq g_0 \leq 1$. A finite-size method based on the Schr\"odinger functional is employed, which enables us to perform all calculations at zero or nearly zero quark mass. As a by-product the critical hopping parameter $\kappa_c$ is obtained at all couplings considered.