Production of a twin single hypernuclei and the Ξ−-nuclear interaction

Abstract

An event accompanied by two single hyperfragments emitted from a Ξ − nuclear capture at rest was found in a nuclear emulsion. It is interpreted as a Ξ −- 12C bound system decaying into either a) Λ 4H + Λ 9Be, b) Λ 4 H + Λ 9 Be ∗ or c) Λ 4 H ∗ + Λ 9 Be . The binding energy of the Ξ- 12C system is obtained as a) 3.70 −0.19 +0.18 MeV, b) 0.62 −0.19 +0.18 MeV and c) 2.66 −0.19 +0.18 MeV, respectively. The system is considered as a Ξ − hypernucleus in the cases a) and c). In case b), this event and another event of the same type (Yokohama event) can both be interpreted as a decay from the Ξ- 12C system in 2P state when a shallow Ξ −-nuclear potential is assumed.