Microscopic self-energy of ${}^{40}$Ca from the charge-dependent Bonn potential

TL;DR

This paper investigates the nucleon self-energy in calcium-40 using the charge-dependent Bonn interaction, highlighting the importance of non-locality and orbital angular momentum dependence for accurate microscopic and dispersive optical-model analyses.

Contribution

It provides a detailed microscopic calculation of the self-energy in calcium-40, emphasizing the role of non-locality and comparing with dispersive optical-model results.

Findings

Microscopic self-energy is more mean-field-like than DOM results.

Surface absorption is underrepresented in the microscopic model.

Non-locality can be effectively modeled with a Gaussian function.

Abstract

The effects of short-range correlations on the nucleon self-energy in $^{40}$Ca are investigated using the charge-dependent Bonn (CDBonn) interaction. Comparisons are made with recent results for the self-energy of $^{40}$Ca derived from the dispersive optical-model (DOM). Particular emphasis is placed on the non-locality of the imaginary part of the microscopic self-energy which suggests that future DOM analyses should include this feature. In particular, data below the Fermi energy appear sensitive to the implied orbital angular momentum dependence of the self-energy. Quasiparticle properties obtained for the CDBonn interaction are substantially more mean-field-like than the corresponding DOM results with spectroscopic factors larger by about 0.2 e.g. Reaction cross sections obtained from the microscopic self-energy for scattering energies up to 100 MeV indicate that an adequate description of volume absorption is obtained while a considerable fraction of surface absorption is missing. The analysis of the non-locality of the imaginary part of the microscopic self-energy suggests that a simple gaussian provides an adequate description, albeit with rather large values for $\beta$, the non-locality parameter.