Three- and four-body cluster models of hypernuclei using the G-matrix ΛN interaction - ⁹_ΛBe, ¹³_ΛC, ⁶_ΛΛHe and & ¹⁰_ΛΛBe

The structure calculations of ⁵_ΛHe, ⁹_ΛBe, ¹³_ΛC, ¹⁰_ΛΛBe and ⁶_ΛΛHe are carried out with an accurate three- and four-body model method in which all rearrangement Jacobian coordinates and associated Gaussian basis functions are taken. The characteristic properties of the spin-independent parts of five kinds of YNG AN interactions are focused on. We propose to improve the strengths of the odd-state parts in a systematic way. The improved YNG interaction explains the B_Λ(⁵_ΛHe) and BΛ(⁹_ΛBe) consistently without an additional three-body force. By employing the 3α + Λ four-body model together with the improved YNG interactions, the second 1/2⁺ state of ¹³_ΛC is predicted as a bound state at approximately 1 MeV below the lowest threshold. The four-body model enables us to find that response to the addition of the A particle to the core nucleus ¹²C is very different for the ground and second 0⁺ states. With the improved YNG interaction and the OBE-simulating ΛΛ interaction, the observed B_ΛΛ(¹⁰_ΛΛBe) is reproduced in the framework of the 2α + 2Λ four-body model. A new theoretical prediction for B_ΛΛ(⁶_ΛΛ) is made with the α + 2Λ three-body model.