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

Abstract

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 gluelike role of $Λ$ hyperon is universal for all $Λ$-hypernuclei considered. However, $Ξ^-$ hyperon has the gluelike role only for the protons distribution in nuclei, and for the neutrons distribution $Ξ^-$ hyperon plays a repulsive role. On the other hand, $Ξ^0$ hyperon attracts surrounding neutrons and reveals a repulsive force to the protons. Possible explanations of the above observation are discussed.