Effective field theory for radiative corrections to charged-current processes. II. Axial-vector coupling

We discuss the hadronic structure-dependent radiative corrections to the axial-vector coupling that controls single-nucleon weak charged-current processes---commonly denoted by ${g}_{A}$. We match the Standard Model at the GeV scale onto chiral perturbation theory at next-to-leading order in the one-nucleon sector, in the presence of electromagnetic and weak interactions. As a result, we provide a representation for the corrections to ${g}_{A}$ in terms of infrared finite convolutions of simple kernels with the single-nucleon matrix elements of time-ordered products of two and three quark bilinears (vector, axial-vector, and pseudoscalar). We discuss strategies to determine the required nonperturbative input from data, lattice-QCD ($+\mathrm{QED}$), and possibly hadronic models. This work paves the way for a precise comparison of the values of the ratio ${g}_{A}/{g}_{V}$ extracted from experiment and from lattice QCD, which constrain physics beyond the Standard Model.