The πσ-axial exchange current
Abstract The axial exchange current operator that arises from the coupling of the axial field to the pion and effective scalar field in nuclei is constructed using the modified σ -model. The corresponding effective one-body operator is then constructed using short range correlation functions determined from realistic nucleon-nucleon interaction models. It is shown that the “πσ”- axial exchange current can contribute about 5% to the quenching of the nucleon axial current coupling constant g A GT in heavy nuclei.