Nuclear $\beta$- and $\gamma$- Collective Bands in the SU$_q$(2) Rotator Model

The SU$_q$(2) rotator model is used for describing the $\beta_1$- and $\gamma_1$-bands of even-even rare earth and actinide collective nuclei. Good results are obtained in nuclei with valence pair number $N>10$. It is shown that in the excited bands the violation of the exact SU(2) symmetry is generally stronger than in the ground state bands, indicating the presence of a nonadiabatic perturbation caused by the excited vibrational degrees of freedom. The physical content of the parameter $q$ is discussed. Predictions of the SU$_q$(2) model for B(E2) intraband transitions in excited bands are presented and the need for specific experimental data is pointed out.