Dirac analyses of proton inelastic scatterings from an s-d shell nucleus 20Ne

Proton inelastic scatterings from an s-d shell nucleus 20Ne are analyzed using an optical potential model in the Dirac coupled channel formalism. Lorentz covariant scalar and vector optical potentials are included in the calculation, and the first-order rotational collective model is used to obtain the transition potentials for the low-lying excited collective states of the ground state rotational band of the nucleus. Dirac coupled channel equations are solved phenomenologically to reproduce the differential cross section and analyzing power data by varying the optical potential and deformation parameters. The multistep process via coupled channels turns out to be important in describing the 4+ excited state of the ground state rotational band. The calculated deformation parameters of the excited states are compared with those of nonrelativistic calculations based on the Schrödinger equations. The Dirac equations are reduced to obtain Schrödinger-like second-order differential equations, and the obtained effective central and spin-orbit optical potentials are analyzed and compared with those of other s-d shell nuclei.