Four-body structure of Λ7Li and ΛN spin-dependent interaction

Two spin-doublet states in Li-7(Lambda) are studied on the basis of the alpha+Lambda+n+p four-body model. We employ the two-body interactions that reproduce the observed properties of any subsystems composed of alpha N,alpha Lambda, alpha NN, and alpha Lambda N. Furthermore, the Lambda N interaction is adjusted so as to reproduce the 0(+)-1(+) splitting of in H-4(Lambda). The calculated energy splittings of 3/2(+)-1/2(+) and 7/2(+)-5/2(+) states in Li-7(Lambda) are 0.69 and 0.46 MeV, which are in good agreement with the recent observed data. The spin-dependent components of the Lambda N interaction are discussed.