Shallow and diffuse spin-orbit potential for proton elastic scattering from neutron-rich helium isotopes at 71 MeV/nucleon

TL;DR

This study measures proton elastic scattering from neutron-rich helium isotopes at 71 MeV/nucleon, revealing that the spin-orbit potential is shallower and more diffuse than in stable nuclei, indicating modifications in neutron-rich environments.

Contribution

It provides the first phenomenological analysis of the spin-orbit potential for neutron-rich helium isotopes at this energy, highlighting modifications compared to stable nuclei.

Findings

Spin-orbit potential is shallower and more diffuse in neutron-rich helium.

The matter radius closely matches the root-mean-square radius of the spin-orbit potential.

Evidence suggests modifications of the spin-orbit interaction in neutron-rich nuclei.

Abstract

Vector analyzing powers for proton elastic scattering from 8He at 71 MeV/nucleon have been measured using a solid polarized proton target operated in a low magnetic field of 0.1 T. The spin-orbit potential obtained from a phenomenological optical model analysis is found to be significantly shallower and more diffuse than the global systematics of stable nuclei, which is an indication that the spin-orbit potential is modified for scattering involving neutron-rich nuclei. A close similarity between the matter radius and the root-mean-square radius of the spin-orbit potential is also identified.