Axial coupling from matching constituent quark model to QCD

TL;DR

This paper estimates the axial-vector coupling of a constituent quark by matching a constituent quark model to QCD operator product expansion, resulting in a value consistent with existing models.

Contribution

It introduces a method to derive the axial coupling constant from QCD matching, providing a theoretical estimate aligned with prior model results.

Findings

Estimated g_A ≈ 0.80 from QCD matching

Agreement with existing model estimates

Method applicable in large N_c limit

Abstract

The axial-vector coupling $g_A$ of a constituent quark is estimated from matching the constituent quark model to the operator product expansion in QCD in the limit of large number of colours under some assumptions. The obtained relation is $g_A\simeq\sqrt{7/11}\approx0.80$, which is in agreement with the existing model estimates.