Quark-model predictions for the ΞN interaction and the implications for Ξ hypernuclei

The SU6 quark-model baryon-baryon interaction by the Kyoto-Niigata group is applied to predict hyperon properties in a nuclear medium. Single-hyperon potentials in finite nuclei are generated by folding G-matrices in symmetric nuclear matter in a local density approximation. The Σ-nucleus potential, which serves as a measure of the predictive capability of the potential model, turns out to be consistent with experiment. That is, it is weakly attractive at the nuclear surface and repulsive inside the nucleus. The Ξ-nucleus potential is also attractive at the nuclear surface but oscillates around zero inside. This strength of the Ξ-nucleus potential is different from the presently accepted value of the depth of around 15 MeV. We carried out an independent analysis of the (K-,K+) Ξ- production spectrum on 12C and found that the experimental data can be explained by the Ξ-nucleus potential obtained from the quark-model interaction.