On the axial charge and other static properties of the quark core in nucleons

We present calculations of the axial vector constant gsub(A) in models where relativistic quarks are confined by scalar potentials, with special emphasis on center-of-mass corrections and pion cloud effects. It is demonstrated that pionic contributions to gsub(A) from a fsub(π)dsub(μ)phi term in the axial current vanish for finite pion mass. Confining potentials of the form crsup(n) with n = 2, 3 give acceptable values for gsub(A) together with quark core radii between 0.5 and 0.6 fm. We also calculate the pion-nucleon coupling constant and establish a connection between gsub(A) and the quark core part of the magnetic moment, including center-of-mass corrections. About half of the proton magnetic moments is shown to come from the quark core. (orig.)