Different effect of the hyperons Λ and Ξ on the nuclear core

We demonstrate the different effect of strange impurities (Λ and Ξ) on the static properties of nuclei within the framework of the relativistic mean-field model. Systematic calculations show that the glue-like role of the Λ-hyperon is universal for all Λ-hypernuclei considered. However, the Ξ--hyperon has a glue-like role only for the protons distribution in nuclei, while for the neutrons distribution it plays a repulsive role. On the other hand, the Ξ0-hyperon attracts the surrounding neutrons and reveals a repulsive force to the protons. Possible explanations of the above observation are discussed. (orig.)