The nucleon axial-vector coupling beyond one loop

TL;DR

This paper investigates the nucleon axial-vector coupling using two-loop chiral perturbation theory, emphasizing the need for low pion mass lattice data for accurate chiral extrapolations.

Contribution

It provides a detailed two-loop analysis of the nucleon axial-vector coupling within chiral perturbation theory, extending previous one-loop studies.

Findings

Chiral extrapolations require lattice data with pion masses below 300 MeV.

Two-loop corrections significantly impact the axial-vector coupling calculations.

Guidelines for lattice simulations to improve chiral extrapolations.

Abstract

We analyze the nucleon axial-vector coupling to two loops in chiral perturbation theory. We show that chiral extrapolations based on this representation require lattice data with pion masses below 300 MeV.