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

TL;DR

This study investigates the nucleon axial charge using quenched lattice QCD with domain wall fermions and an improved gauge action, highlighting the importance of finite volume effects on the results.

Contribution

It introduces the use of a RG-improved gauge action to reduce lattice artifacts and examines finite volume effects on nucleon axial charge calculations.

Findings

Finite volume effects are significant in nucleon axial charge calculations.

Improved gauge action maintains good chiral behavior on coarse lattices.

Preliminary results indicate volume effects influence the axial charge estimate.

Abstract

In our previous DWF calculation with the Wilson gauge action at $\beta=6.0$ ($a^{-1}\simeq$ 1.9 GeV) on a $16^3 \times 32 \times 16$ lattice, we found that $\Ga$ had a fairly strong dependence on the quark mass. A simple linear extrapolation of $\Ga$ to the chiral limit yielded a value that was almost a factor of two smaller than the experimental one. Here we report our recent study of this issue. In particular, we investigate possible errors arising from finite lattice volume, especially in the lighter quark mass region. We employ a RG-improved gauge action (DBW2), which maintains very good chiral behavior even on a coarse lattice ($a^{-1}\simeq$ 1.3 GeV), in order to perform simulations at large physical volume ($> (2{\rm fm})^3$). Our preliminary results suggest that the finite volume effect is significant.