Non-perturbative renormalization of vector and axial vector currents in quenched QCD for a renormalization group improved gauge action

TL;DR

This paper non-perturbatively determines the renormalization constants for vector and axial-vector currents in quenched QCD using an improved gauge action, leading to more accurate meson decay constants and better scaling behavior.

Contribution

It introduces a non-perturbative method to compute renormalization constants in quenched QCD with an RG-improved gauge action, improving the accuracy of decay constant calculations.

Findings

Better scaling of meson decay constants with non-perturbative Z-factors

Significant improvement over perturbative Z-factor estimates

Enhanced reliability of lattice QCD results for decay constants

Abstract

Renormalization constants of vector ($Z_V$) and axial-vector ($Z_A$) currents are determined non-perturbatively in quenched QCD for an RG-improved gauge action and a tadpole-improved clover quark action using the Schr\"odinger functional method. Meson decay constants $f_\rho$ and $f_\pi$ show much better scaling when $Z_V$ and $Z_A$ estimated for infinite physical volume are used instead of $Z$-factors from tadpole-improved one-loop perturbation theory.