Δ(1232)isobar excitations and the ground state of nuclei

Abstract

The influence of $\ensuremath{\Delta}$ isobar components on the ground-state properties of nuclear systems is investigated for nuclear matter as well as finite nuclei. Many-body wave functions, including isobar configurations and binding energies, are evaluated employing the framework of the coupled-cluster theory. It is demonstrated that the effect of isobar configurations depends in a rather sensitive way on the model used for the baryon-baryon interaction. As examples for realistic baryon-baryon interactions with explicit inclusion of isobar channels we use the local $(V28)$ and nonlocal meson-exchange potentials $({\mathrm{Bonn}}_{2000})$ but also a model recently developed by the Salamanca group, which is based on a quark picture. The differences obtained for the nuclear observables are related to the treatment of the interaction, the \ensuremath{\pi}-exchange contributions in particular, at high momentum transfers.