Chinese Acad Sci, Inst High Energy Phys, Beijing 100039, Peoples R China
; Chinese Acad Sci, Inst Theoret Phys, Beijing 100080, Peoples R China
In this paper the nuclear structure of hypernucleus He-5(Lambda) and its effect on the binding energy B-Lambda of Lambda hyperon are systematically studied. The polarization effect of the core alpha is explored. The binding energy B-Lambda of He-5(Lambda) including D-state mixing component is calculated. The results show that the core alpha suffers a serious distortion by the interaction with Lambda hyperon and has no longer the structure of a free Alpha particle. The D-state mixing can improve the B-Lambda calculated value about 0.5 MeV. A possible three cluster structure is further explored. The Lambda + d + d model can give a B-Lambda value close to the experimental one. The further exploration is necessary.