Comparisons of electric charge and axial charge meson cloud   distributions in the PCQM
  The meson cloud distributions in $r$-space are extracted from the nucleon electromagnetic and axial form factors which are derived in the perturbative chiral quark model. The theoretical results indicate that the electric charge and axial charge distributions of the three-quark core are the same, the magnetic charge distributions of the meson cloud and three-quark core are more or less in the same region and peak at distances of around 2 $\rm GeV^{-1}$, but the axial charge meson cloud distributes mainly inside the three-quark core. 
X. Y. Liu, K. Khosonthongkee, A. Limphirat and Y. Yan
hep-ph nucl-th