Calculation of a complete set of spin observables for proton elastic scattering from stable and unstable nuclei

TL;DR

This paper presents a comprehensive relativistic approach to calculate spin observables in proton elastic scattering from both stable and unstable nuclei, comparing different theoretical models and potential formulations to improve predictive accuracy.

Contribution

It introduces a detailed comparison of IA1 and IA2 formalisms, full-folding versus factorized potentials, and local versus non-local optical potentials for unstable nuclei at intermediate energies.

Findings

Full-folding optical potentials improve scattering observables at 200 MeV.

No significant difference between models at 500 MeV.

Non-local potentials provide comparable results to local ones.

Abstract

A microscopic study of proton elastic scattering from unstable nuclei at intermediate energies using a relativistic formalism is presented. We have employed both the original relativistic impulse approximation (IA1) and the generalised impulse approximation (IA2) formalisms to calculate the relativistic optical potentials, with target densities derived from relativistic mean field (RMF) theory using the NL3 and FSUGold parameter sets. Comparisons between the optical potentials computed using both IA1 and IA2 formalisms, and the different RMF Lagrangians are presented for both stable and unstable targets. The comparisons are required to study the effect of using IA1 versus IA2 optical potentials, with different RMF parameter sets, on elastic scattering observables for unstable targets at intermediate energies. We also study the effect of full-folding versus the factorized form of the optical potentials on elastic scattering observables. As with the case for stable nuclei, we found that the use of the full-folding optical potential improves the scattering observables (especially spin observables) at low intermediate energy (e.g. 200MeV). No discernible difference is found at a projectile incident energy of 500 MeV. To check the validity of using localized optical potential, we calculate the scattering observables using non-local potentials by solving the momentum space Dirac equation. The Dirac equation is transformed to two coupled Lippmann-Schwinger equations, which are then numerically solved to obtain elastic scattering observables. The results are discussed and compared to calculations involving local coordinate-space optical potentials.