Neutron-Incident Phenomenological Dirac Optical Model Potential

Some proton-incident data have been published on elastic-scattering and total-reaction cross sections in the intermediate energy region. Such results as well as experimental data obtained by polarized proton beams are useful for parametrizing global optical model potentials in detail. In contrast, neutronincident experiments on elastic scattering are more difficult than proton ones, so that there is a limitation on neutron-incident data. It is, therefore, interesting to convert the proton-incident global optical model potentials into neutron-incident ones. The authors introduce (N-Z)/A dependent symmetry potential terms to the proton-incident optical potentials, and then obtain neutron-incident ones. The neutron potentials reproduce total cross sections in an acceptable degree. However, a comparison with potentials proposed by other authors brings about a confused situation in the sign of the symmetry terms.