Strangeness -2 hypertriton

Abstract

We have solved for the first time the Faddeev equations for the bound state problem of the coupled $\Lambda\Lambda N$--$\Xi NN$ system to study whether an hypertriton with strangeness -2 may exist or not. We make use of the interactions obtained from a chiral quark model describing the low-energy observables of the two-baryon systems with strangeness 0, -1, and -2 and three-baryon systems with strangeness 0 and -1. The $\Lambda\Lambda N$ system alone is unbound. However, when the full coupling to $\Xi NN$ is considered, the strangeness -2 three-baryon system with quantum numbers $(I,J^P)=(1/2,1/2^+)$ becomes bound, with a binding energy of about 0.5 MeV. This result is compatible with the non-existence of a stable $^3_\Lambda$H with isospin one.