Observation of a 6∧∧ He double hypernucleus

Abstract

A double-hyperfragment event has been found in a hybrid-emulsion experiment. It is identified uniquely as the sequential decay of 6∧ ∧ He emitted from a hyperon nuclear capture at rest. The mas of 6∧∧ He and the ∧ − ∧ interaction energy ΔB∧ ∧ have been measured for the first time devoid of the ambiguities due to the possibilities of excited states. The value of ΔB∧∧ is 1.01 ± 0.20+ 0.018-0.11MeV. This demonstrates that the ∧ − ∧ interaction is weakly attractive. © 2001 The American Physical Society.