${\Xi }^{-}t$ quasibound state instead of $\Lambda \Lambda nn$ bound state

Abstract

We study the coupled $\Lambda \Lambda nn-{\Xi }^{-}pnn$ system to check whether the inclusion of channel coupling is able to bind the $\Lambda \Lambda nn$ system. We use a separable potential three-body model of the coupled $\Lambda \Lambda nn-{\Xi }^{-}pnn$ system as well as a variational four-body calculation with realistic interactions. Our results exclude the possibility of a $\Lambda \Lambda nn$ bound state by a large margin. However, we have found a ${\Xi }^{-}t$ quasibound state above the $\Lambda \Lambda nn$ threshold.

Comments: 16 pages. To be published in Chinese Physics C