Asymmetry dependence of Gogny based optical potential

TL;DR

This paper investigates neutron and proton scattering on calcium isotopes using the Nuclear Structure Method with Gogny D1S interaction, highlighting successes and limitations in describing scattering observables.

Contribution

It applies the NSM with Gogny D1S to model optical potentials for calcium isotopes and proposes a correction method for proton scattering discrepancies.

Findings

NSM accurately describes neutron and proton elastic scattering on $^{40}$Ca.

NSM fails to reproduce absorption in proton scattering on $^{48}$Ca.

A Perey-Buck based correction improves the model's agreement with data.

Abstract

An analysis of neutron and proton scattering off $^{40,48}$Ca has been carried out. Real and imaginary potentials have been generated using the Nuclear Structure Method (NSM) for scattering with the Gogny D1S nucleon-nucleon effective interaction. Observables are well described by NSM for neutron and proton elastic scattering off $^{40}$Ca and for neutron scattering off $^{48}$Ca. For proton scattering off $^{48}$Ca, NSM yields a lack of absorption. This discrepancy is attributed to double-charge-exchange contribution and coupling to Gamow- Teller mode which are not included in the present version of NSM. A recipe based on a Perey-Buck fit of NSM imaginary potential and Lane model is proposed to overcome this issue in an approximate way.