An α-cluster model for 9Λ Be spectroscopy

An alpha-cluster model is applied to study low-lying spectrum of the (I >) (9) Be hypernucleus. The three-body alpha alpha I > problem is numerically solved by the Faddeev equations in configuration space using phenomenological pair potentials. We found a set of the potentials that reproduces experimental data for the ground state (1/2(+)) binding energy and excitation energy of the 5/2(+) and 3/2(+) states, simultaneously. This set includes the Ali-Bodmer potential of the version "e" for alpha alpha and modified Tang-Herndon potential for alpha I > interactions. The spin-orbit alpha I > interaction is given by modified Scheerbaum potential. Low-lying energy levels are evaluated applying a variant of the analytical continuation method in the coupling constant. It is shown that the spectral properties of (I >) (9) Be can be classified as an analog of Be-9 spectrum with the exception of several "genuine hypernuclear states". This agrees qualitatively with previous studies. The results are compared with experimental data and new interpretation of the spectral structure is discussed.