Bonn 2020 – scientific programme
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HK: Fachverband Physik der Hadronen und Kerne
HK 52: Poster (b)
HK 52.14: Poster
Thursday, April 2, 2020, 16:30–18:30, Grotte
Has the ΛΛ4n been observed? — Sebastian Bleser1, •Michael Bölting1, Theodoros Gaitanos2, Josef Pochodzalla1,3, Falk Schupp1, and Marcell Steinen1 — 1Helmholtz-Institut Mainz, Deutschland — 2Aristoteles-Universität Thessaloniki, Griechenland — 3Institut für Kernphysik, Johannes Gutenberg-Universität Mainz, Deutschland
Despite several promising experimental results, the question whether bound or resonant light neutral nuclei exist is not yet answered beyond doubt. The E906 experiment was the first fully electronic experiment to produce and study double hypernuclei with large statistics [J. K. Ahn et al., Phys. Rev. Lett. 87, 132504 (2001)]. We show, that the interpreatation of the dominant structure in the correlated π−π− momentum matrix at (133, 114) MeV/c in terms of Λ3H + Λ4H remains questionable. Neither hypernuclei production from stopped Ξ− by a 9Be nuclues 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 that decays of the ΛΛ4n may be responsible for the observed structure. Indeed, the inclusion of ΛΛ4n with a two-body π− branching ratio of 50% in a statistical multifragmentation model allows to describe the E906 data remarkably well. This interpretation is, however, hampered by the fact, that this neutral nucleus is predicted to be unbound.