Boson description of low-lying collective states in 128Ba

The low-lying collective states in Ba-128 are investigated microscopically by means of the boson expansion theory with the self-consistent effective interactions. Calculated level structures and electromagnetic properties are compared with the experimental data. Theoretical structures of the collective wave functions are illustrated in detail for 0(1)(+), 0(2)(+), 0(3)(+), 2(1)(+), 2(2)(+), and 2(3)(+) states. In the present results, the main contribution to the 0(2)(+) state of Ba-128 comes from the three-phonon component, and the two-phonon component is rather dominant in the 0(3)(+) state. The description of the wave functions is compared to the results of the general collective model.