The Jülich hyperon-nucleon interaction models

Abstract

Hyperon-nucleon interaction models (A, B), which have been developed in the meson-exchange framework by the Julich group, are reviewed, with some emphasis on characteristic conceptual differences compared to corresponding interactions constructed by the Nijmegen group. We report on two new versionsA and\(\tilde B\) in which the explicit energydependence of the original models A and B is removed in order to simplify application in nuclear structure calculations. As a byproduct of our analysis we find that the resulting SU(3)-parameters likeF/(F+D) ratios do depend on the specific model used an on approximations applied. While all models provide a reasonable description of the scarce cross-section data, sizeable differences occur in the, so far unmeasured, spin observables, especially between our models and the Nijmegen soft-core model NSC. This demonstrates clearly that a measurement of such observables can easily discriminate between present models and thus shed some light on various aspects of the hyperon-nucleon interactions like e.g. the proper choice of parameter constraints. In addition, the results obtained with the energy-independent potentials (A,\(\tilde B\)) in a conventional first-order Brueckner calculation for a λ-hyperon in nuclear matter are presented. The binding energy BΛ(∞) of a λ-hyperon in nuclear matter was found to be 29.8 MeV (32.0 MeV) for model A(\(\tilde B\).