6533b7d0fe1ef96bd125b5ca

RESEARCH PRODUCT

Has the neutral double hypernucleus nΛΛ4 been observed?

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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 therefore explored the conjecture of Avraham Gal that decays of the may be responsible for the observed structure. Indeed, the inclusion of with a two-body π − branching ratio of 50% in a statistical multifragmentation model allows to describe the E906 data remarkably well. On the other hand, a bound Λ 3 n nucleus would cause a striking structure in the momentum correlation matrix which is clearly inconsistent with the observation of E906.