The spin-independent YN interaction is investigated through studying the structure of the 9ΛBe hypernucleus. 9ΛBe consists of four protons, four neutrons and one Λ hyperon. The alpha-cluster model makes the simple ααΛ three-body system from complex 9ΛBe system. In this model, the potential of YN in the 9ΛBe hypernucleus becomes spin-independent. The structure of 9ΛBe is studied by solving the Schro ̈dinger equation. In order to solve this equation, the wavefunction and potential of 9ΛBe is essential. The wavefunction of the ααΛ system is obtained by using the Gaussian Expansion Method (GEM) and the Rayleigh-Ritz variational method. Also theΛα and αα interactions are needed for solving the Schro ̈dinger equation because GEM acts in Jacobi coordinate. The G-matrix theory constructs the YNG interaction from various YN potential models. The YNG interactions operate on between Λ and α. The Ali-Bodmer potential is employed as an αα interaction. In this thesis, the 9ΛBe structure is studied by considering only the l = 0 system. By comparing the density probability of 8Be and 9ΛBe, glue-like role which is one of the characters of hypernuclei is verified. The ground-state energy of 9ΛBe is obtained depending on the YN potential models. All of the calculated ground-state energy are lower than the experimental value. It is called over-binding. The next, we are planning to calculate the ground-state energy with considering the l = 2 system between α and Λ. We plan on employing the new αα potential which is more correct than the Ali-Bodmer potential model. Also the YN potential models will be improved by considering the shell model picture.
Thesis Advisor: Prof. Yongseok Oh