Abstract
The properties of the low-lying positive parity states of
160
70Yb
90 are reported and compared with predictions of the IBA-2 model based on parameters extrapolated from earlier calculations on the lighter,
N = 90 isotones. There is good agreement between theory and experiment. The results confirm the predicted transition between the SU(3) and O(6) limits of the IBA for the
N = 90 isotones, and point to a new region of O(6) symmetry.