Mass-number and isotope dependence of the local microscopic optical potential for polarized proton scattering

TL;DR

This paper systematically derives local microscopic optical potentials for polarized proton scattering across a wide mass range, revealing how target density and nuclear structure influence the potential's geometry and strength.

Contribution

It introduces a systematic method to derive local microscopic optical potentials for various nuclei, including unstable and halo nuclei, and analyzes the effects of density broadening on the potential.

Findings

The potentials reproduce experimental data systematically.

Density broadening affects the real spin-orbit and central parts differently.

Halo nuclei show significant density-broadening effects.

Abstract

We derive local microscopic optical potentials $U$ systematically for polarized proton scattering at 65~MeV using the local-potential version of the Melbourne $g$-matrix folding model. As target nuclei, we take $^{6}$He and neutron-rich Ne isotopes in addition to stable nuclei of mass number $A=4$--$208$ in order to clarify mass-number and isotope dependence of $U$. The local potentials reproduce the experimental data systematically and have geometries similar to the phenomenological optical potentials for stable targets. The target density is broadened by the weak-binding nature and/or deformation of unstable nuclei. For the real spin-orbit part of $U$ the density broadening weakens the strength and enlarges the radius, whereas for the central part it enlarges both of the strength and the radius. The density-broadening effect is conspicuous for halo nuclei such as $^{6}$He and $^{31}$Ne. Similar discussions are made briefly for proton scattering at 200~MeV. We briefly investigate how the isovector and the non spherical components of $U$ affect proton scattering.