Has the neutral double hypernucleus nΛΛ4 been observed?

Abstract The BNL-AGS E906 experiment was the first fully electronic experiment to produce and study double hypernuclei with large statistics. Two dominant structures were observed in the correlated π − – π − momentum matrix at ( p π − H , p π − L ) = ( 133 , 114 ) MeV / c and at ( 114 , 104 ) MeV / c . In this work we argue that the interpretation of the structure at ( 133 , 114 ) MeV / c in terms of Λ 3 H+ Λ 4 H pairs is questionable. We show, that neither a scenario where these single-Λ hypernuclei are produced after capture of a stopped Ξ − by a 9Be nucleus nor interactions of energetic Ξ − with 9Be nuclei in the target material can produce a sufficient amount of such twin pairs. We have…