Domain wall fermion calculation of nucleon g_A/g_V

TL;DR

This paper reports a lattice-QCD calculation using domain-wall fermions to determine the nucleon's isovector vector and axial charges, providing a direct continuum ratio without separate renormalization factors.

Contribution

The study demonstrates that the lattice ratio g_A/g_V directly yields the continuum value due to identical renormalizations in domain-wall fermions, simplifying the calculation process.

Findings

Z_V and Z_A agree closely, validating the method.

The lattice ratio g_A/g_V matches continuum expectations.

Additional spin-related quantities are also obtained.

Abstract

We present a preliminary domain-wall fermion lattice-QCD calculation of isovector vector and axial charges, g_V and g_A, of the nucleon. Since the lattice renormalizations, Z_V and Z_A, of the currents are identical with DWF, the lattice ratio (g_A/g_V)^{lattice} directly yields the continuum value. Indeed Z_V determined from the matrix element of the vector current agrees closely with Z_A from a non-perturbative renormalization study of quark bilinears. We also obtain spin related quantities Delta-q/g_V and delta-q/g_V.