Structure Evolution in the Even-Even 124–134Xe with IBM2

We have investigated the structure evolution of the 124–134Xe isotopic chain in the framework of the proton-neutron interacting model IBM2. The positive parity spectra of the ground state, quasi-β and quasi-γ bands are reproduced well. The staggering in 124–130Xe are almost completely removed and the γ band agree well with the experiment data, even for the high-spin quasi-γ states. The key quantities of the collective structure evolution, including level energies, the B(E2) transition branching ratios, and the M1 excitations to 1+1 mixer-symmetry states are analyzed by comparing with the experimental data. The parameters for representation of the Oπν(6) and SU*πν(3) features in isotopes are examined. Both experimental data and theoretical results show that the shape phase transition of 124–134Xe isotopic chain is from the SU*πν(3) (triaxial rotation) to the Uπν(5) (vibration motion) with a considerable constituent of the Oπν(6) symmetry (γ-unstable rotation), where the shape phase transition rapidly takes place between the neutron number N = 76 and N = 78. (nuclear physics)