ΛΛ-Ξ N coupling effects in light hypernuclei

Abstract:

The significance of ΛΛ-Ξ N 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 0.43MeV 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-Ξ N 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 ( ΔB _ΛΛ) of ⁵ _ΛΛ He is about 0.27MeV 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 ΔB _ΛΛ.-1