To bind or not to bind: ΛΛ hypernuclei and Ξ hyperons Original Research Article

Faddeev calculations suggest that: (i) BΛΛ(ΛΛ6He) for the recent KEK emulsion event is compatible with fairly weak ΛΛ potentials VΛΛ such as due to the Nijmegen soft-core NSC97 model; (ii) the isodoublet ΛΛ5H - ΛΛ5He hypernuclei are particle-stable ven in the limit VΛΛ → 0; and (iii) ΛΛ4H within a ΛΛd model is particle-stable. However, four-boudy ΛΛpn Faddeev-Yakubovsky calculations do not produce a bound state for ΛΛ4H even for VΛΛ considerably stronger than required to reproduce BΛΛ(ΛΛ6He), in contrast to the normal situation (e.g. ΛΛ10Be) where a four-body Faddeev-Yakubovsky calculation yields stronger binding than that due to a suitably defined three-body Faddeev calculation. For stranger systems, Faddeev calculations using ΛΞ interactions which simulate model NSC97 suggest that ΛΞ6He marks the onset of nuclear stability for Ξ hyperons.