Non-perturbative improvement and renormalization of the axial current in N_f=3 lattice QCD

TL;DR

This paper presents a non-perturbative calculation of the axial current renormalization factor Z_A and the improvement coefficient c_A in three-flavor lattice QCD, enhancing the precision of theoretical predictions.

Contribution

It provides the first non-perturbative determination of Z_A and c_A in three-flavor O(a) improved lattice QCD with Wilson quarks using a Schrödinger functional setup.

Findings

Non-perturbative Z_A value obtained at constant physics.

Determination of the improvement coefficient c_A.

Reduction of finite quark mass effects in renormalization.

Abstract

We report on a non-perturbative computation of the renormalization factor Z_A of the axial vector current in three-flavour O(a) improved lattice QCD with Wilson quarks and tree-level Symanzik improved gauge action and also recall our recent determination of the improvement coefficient c_A. Our normalization and improvement conditions are formulated at constant physics in a Schr\"odinger functional setup. The normalization condition exploits the full, massive axial Ward identity to reduce finite quark mass effects in the evaluation of Z_A and correlators with boundary wave functions to suppress excited state contributions in the pseudoscalar channel.