ΛΛ-ΞN coupling effects in light hypernuclei

摘要

The significance of ΛΛ-ΞN coupling in double-Λ hypernuclei has been studied. The Pauli suppression effect due to this coupling in ~6_(ΛΛ)He has been found to be 0.43 MeV for the coupling strength of the NSC97e potential. This indicates that the free-space ΛΛ interaction is stronger by an about 5 °phase shift than that deduced from the empirical data of ~6_(ΛΛ)He without including the Pauli suppression effect. In ~5_(ΛΛ) He and ~5_(ΛΛ) H, an attractive term arising from the ΛΛ-ΞN conversion is enhanced by the formation of an alpha-particle in the intermediate Ξ states. According to this enhancement, we have found that the ΛΛ binding energy (△B_(ΛΛ)) of ~5_(ΛΛ) He is about 0.27 MeV larger than that of ~6_(ΛΛ) He for the NSC97e coupling strength. This finding deviates from the general picture that the heavier is the core nucleus, the larger is △BΛΛ.