DESCRIPTION OF SUPERDEFORMED NUCLEAR-STATES IN THE INTERACTING BOSON MODEL

We show in this paper that the superdeformed nuclear states can be des cribed with a four parameter formula in the spirit of the perturbated SU(3) limit of the sdg IBM. The E2 transition gamma-ray energies, the dynamical moments of inertia of the lowest superdeformed (SD) bands in even-even Hg, Pb, Gd, and Dy isotopes, and the energy differences Del ta E-gamma-Delta E-gamma(ref) of the SD band 1 of Hg-194 are calculate d. The calculated results agree with experimental data well. This indi cates that the SD states are governed by a rotational interaction plus a perturbation with SOsdg(5) symmetry. The perturbation causing the D elta I=4 bifurcation to emerge in the Delta I=2 superdeformed rotation al band may then possess SOsdg(5) symmetry.