Chiral extrapolation of nucleon axial charge $g_A$ in effective field theory

TL;DR

This paper investigates the extrapolation of the nucleon axial charge $g_A$ using heavy baryon chiral effective field theory, including baryon resonances and finite range regularization, based on lattice data, but finds the extrapolated values are below experimental results.

Contribution

It introduces a chiral effective field theory approach with baryon resonances and finite range regularization for more accurate $g_A$ extrapolation from lattice data.

Findings

Extrapolated $g_A$ values are smaller than experimental at physical pion mass.

Including octet and decuplet baryons affects the extrapolation.

Finite range regularization improves convergence in the chiral expansion.

Abstract

The extrapolation of nucleon axial charge $g_A$ is investigated within the framework of heavy baryon chiral effective field theory. The intermediate octet and decuplet baryons are included in the one loop calculation. Finite range regularization is applied to improve the convergence in the quark-mass expansion. The lattice data from three different groups are used for the extrapolation. At physical pion mass, the extrapolated $g_A$ are all smaller than the experimental value.