Superdeformed Bands with △I = 4 Bifurcation of the Odd-A Nuclei in the A-190 Region

The γ-ray energy (Eγ) spectra of the superdeformed (SD) bands of odd-A nuclei in the A- 190 mass region are investigated systematically. It is found that a △1 = 4 bifurcation exists in the SD bands. Within the supersymmetry scheme including many-body interactions and a perturbation possessing the SO(5) (or SU(5)) symmetry on the rotational symmetry, the Eγ spectra, dynamical moments of inertia and Eγ differences δ4Eγ(I) of these bands are evaluated. Quantitative good results are obtained which show that the scheme is powerful to describe the △I = 4 bifurcation. The △I = 4 bifurcation may then come from the perturbation holding the SO(5) (or SU(5)) symmetry on the rotation. From a microscopic point of view, the △I = 4 bifurcation may be a result of the combination of theβ-phonon, γ-phonon and the rotation.