Strictly finite-range potential for light and heavy nuclei

TL;DR

This paper investigates strictly finite-range potentials for neutrons interacting with nuclei, comparing different models and analyzing their spectral properties and trajectory behaviors, highlighting the advantages of smooth zero-approach potentials over traditional cut-off models.

Contribution

It introduces and compares SFR potentials, including SV and SS, demonstrating their regular trajectory behavior and suitability for nuclear interaction modeling, especially for light nuclei.

Findings

SV and SS potentials have regular S-matrix pole trajectories.

CWS potentials conform to a benchmark when range equals cutoff radius.

Single-term SV potential suffices for light nuclei neutron interactions.

Abstract

Strictly finite-range (SFR) potentials are exactly zero beyond their finite range. Single-particle energies and densities as well as S-matrix pole trajectories are studied in a few SFR potentials suited for the description of neutrons interacting with light and heavy nuclei. The SFR potentials considered are the standard cut-off Woods--Saxon (CWS) potentials and two potentials approaching zero smoothly: the SV potential introduced by Salamon and Vertse and the SS potential of Sahu and Sahu. The parameters of these latter were set so that the potentials may be similar to the CWS shape. The range of the SV and SS potentials scales with the cube root of the mass number of the core like the nuclear radius itself. For light nuclei a single term of the SV potential (with a single parameter) is enough for a good description of the neutron-nucleus interaction. The trajectories are compared with a bench-mark for which the starting points (belonging to potential depth zero) can be determined independently. Even the CWS potential is found to conform to this bench-mark if the range is identified with the cutoff radius. For the CWS potentials some trajectories show irregular shapes, while for the SV and SS potentials all trajectories behave regularly.