Medium-spin γ-ray spectroscopy of the transitional nucleus 160Er

The nucleus 160Er, with the structural parameter R4/2=E(41+)/E(21+)=3.10, falls on the transition path between the critical point of the vibrator-rotor shape phase transition and the rigid rotor limit, thus serving as a critical test of the CBS rotor model, which describes this transition region. Medium-spin states of 160Er have been populated via the reaction 159Tb(6Li,5n) and new levels have been identified and interpreted as the even-spin members of the γ band and members of the β vibrational band. Level energies and branching ratios are compared to the CBS rotor model predictions