Description of Rotation Bands in ^157,158 Er at Ultrahigh Spin

Abstract

Properties of the four rotation bands, 157 Er(1,2) and 158 Er(1,2), at ultrahigh spin are investigated within the supersymmetry scheme including many-body interactions and possessing the SO(5) (or SU( 5)) symmetry on the rotational symmetry. Quantitatively good results of the γ-ray energies and the dynamical moments of inertia in the rotation bands in 157 Er and 158 Er at ultrahigh spin are obtained. We theoretically predict that the competition between the anti-pairing and pairing effects may exist in 157 Er(1,2) and 158 Er(2) bands states. In 158 Er(1) band state, the favourepairing effects may exist and the SO(5) (or SU( 5)) symmetry play a dominant role. There may be sphere coexisting with headecupole deformed in 158 Er(1) rotation band state.