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

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 Schrödinger 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.