The identified ΛΛ-hypernuclei and the predicted H-particle

Abstract

The existence of the H particle, the dihyperon predicted by Jaffe, would bring into question the existence of double hypernuclei. We review the two double hypernucleus events published in the literature. We include an independent report, hitherto unpublished, which was made on the ΛΛ 10 Be event in 1963 and clarifies the salient features of the event; this report reaffirms its published interpretation. We have made a simple calculation of the energy spectrum for Ξ - hyperons produced with K - beams in past emulsion experiments, with a result which accounts adequately for the paucity of reported double hypernucleus events. We outline a hybrid emulsion experiment that would locate Ξ - hyperon interactions efficiently and could thereby greatly improve our knowledge of double hypernuclei.

Hyperonic mixing in five-baryon double-strangeness hypernuclei in a two-channel treatment

“…The reason was that this model is compatible with strong ΛΛ attraction (∆B ΛΛ = 4-5 MeV) supported by earlier data on ΛΛ hypernuclei [21,22]. This strong ΛΛ attraction of NHC-D is due to its specific feature that only the scalar singlet is taken into account.…”

The influence of the strength of hyperon–hyperon interactions on neutron star properties

“…This allows one to determine the value of the Λ well depth in Λ matter at density 0.5ρ 0 (ρ 0 denotes the saturation density) at the level of U Λ Λ ≃ 5 MeV [11]. The results of earlier experiments [12], [13], [14], [15], [16] give the value of U Λ Λ estimated with the use of Nijmegen model D at the level of ≃ 20 MeV [9]. This paper examines the implications of the strength of hyperon-hyperon coupling constants on the β-equilibrated hyperon star matter, hence doing all calculations within the framework of relativistic mean field model with two parameterizations, namely the standard TM1 [17] and TMA [18].…”

“…∆B ΛΛ ( Table 2 compiles experimental values of the two observables mentioned above [13], [15], [14], [12]. The obtained values of ∆B ΛΛ indicate that the Λ − Λ interaction is attractive and rather strong.…”

Hyperon-hyperon interactions with the Nijmegen ESC08 model

“…ΛΛ Be, and 13 ΛΛ B [46] has been changed drastically. This because of the Nagara event [39], identified uniquely as 6 ΛΛ He, which established that the ΛΛ interaction is much weaker (ΔB ΛΛ ≈ 0.7 MeV).…”