Optical-Model Analysis of Proton Elastic Scattering in the Range of 9 to 22 MeV

TLDR

The observed increase of the real well depth with mass number is attributed to a nuclear symmetry term and momentum dependence in the potential. The study investigates how core excitations influence optical‑model parameters and compares the relative importance of volume versus surface imaginary potentials. The authors analyzed 35 elastic‑scattering angular distributions for 9–22 MeV protons with an optical‑model least‑squares fit, derived mass‑ and energy‑dependent parameter formulas, and examined how core excitations affect volume and surface imaginary potentials. Polarization and reaction‑cross‑section measurements agree well with the optical‑model calculations.

Abstract

For incident proton energies between 9 to 22 MeV, 35 elastic scattering angular distributions have been analyzed with the optical model using a least-square criteria over the complete angular range of the data. The observed increase of the real well depth as a function of mass number is explained by the presence of a nuclear symmetry term in the potential and by the momentum dependence of the potential. The polarization and reaction cross-section data are in good agreement with the calculations. The effect of core excitations on the parameters of the optical model are studied, and the relative importance of volume and surface imaginary potentials is discussed. Formulas are given to obtain the value of the parameters of the optical model as a function of mass number and energy.