NEUTRON ELECTRIC-DIPOLE MOMENT IN CHIRAL QUARK-MESON MODELS

The neutron electric dipole moment is calculated in models of the quar k structure of nucleons. The models studied incorporate chiral symmetr y and the axial anomaly. The results are shown to satisfy the requirem ent of vanishing if either the strength of the anomaly or any current quark mass vanishes. In the cloudy-bag model both quark and pion-loop contributions to the dipole moment are found and these reinforce. In t he color-dielectric model, which is consistent with partial conservati on of the axial-vector current, there is only a pion-loop contribution .