Nucleon axial charge from quenched lattice QCD with domain wall fermions and DBW2 gauge action

TL;DR

This paper uses domain wall fermions and the DBW2 gauge action in lattice QCD to accurately calculate the nucleon axial charge, revealing significant volume dependence in the results.

Contribution

It demonstrates the effectiveness of chiral symmetry preservation and improved gauge actions in lattice QCD for precise nucleon axial charge calculations.

Findings

Confirmed volume dependence of axial charge on different lattice sizes

Achieved more accurate WT identity at coarse lattice spacing

Utilized chiral symmetry to simplify renormalization process

Abstract

The domain wall fermion (DWF) method, with its almost perfectly preserved chiral symmetry on the lattice, makes the calculation of the nucleon axial charge particularly easy. By maintaining chiral symmetry and using the Ward-Takahashi (WT) identity, one has Z_A = Z_V and the bare lattice calculation yields the physical value without explicit renormalization. The DBW2 improved gauge action provides further enhancement of the symmetry and hence a more accurate WT identity at coarse lattice spacing. Taking advantage of these methods, we confirmed a significant volume dependence of the nucleon axial charge on (1.2 fm)^3 and (2.4 fm)^3 lattice volumes.