The level structure and grouping into quasibands of ${}_{}{}^{154}{}_{}{}^{}\mathrm{Dy}$ and ${}_{}{}^{156}{}_{}{}^{}\mathrm{Dy}$ is derived in the dynamic pairing-plus-quadrupole model and the analysis is extended to five quasibands in ${}_{}{}^{154}{}_{}{}^{}\mathrm{Dy}$ and seven collective K bands in ${}_{}{}^{156}{}_{}{}^{}\mathrm{Dy}$. The absolute E2 moments, relative B(E2) values for interband transitions and X(E0/E2) are compared with experimental data and the predictions from the boson expansion model and the interacting boson model. The transition at N=88–90 for all observed quantities is reproduced. The anomaly of small $0_g$-$2_{\beta }$ strength in ${}_{}{}^{156}{}_{}{}^{}\mathrm{Dy}$ is explained from our analysis, retaining the collective β-vibration character.

• Received 19 October 1988

DOI:https://doi.org/10.1103/PhysRevC.39.1604