Superdeformed Bands with ΔI = 4 Bifurcation of the Odd-A Nuclei in the A ～ 190 Region

The γ-ray energy (E_γ) spectra of the superdeformed(SD) bands of odd-A nuclei in the A ～ 190 mass region are investigated systematically. It is found that ΔI = 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 E_γ spectra, dynamical moments of inertia and E_γ difference δ⁴E_γ(I) of these bands are evaluated. Quantitative good results are obtained. They show that the scheme is powerful to describe the ΔI = 4 bifurcation. The ΔI = 4 bifurcation may then come from the perturbation holding the SO(5) (or SU(5)) symmetry on the rotation. In a microscopic point of view, the ΔI = 4 bifurcation may be result from the combination among the β-phonon, γ-phonon and the rotation.