The interacting boson model with SU(3) higher-order interactions offers a new route to enlarge our understanding on γ-soft rotation. In this paper, U(5)-like and O(6)-like new γ-softness are found, in which the corresponding energy levels in the ground band and the quasi-γ band can be exactly degenerate, and have a partial O(5) dynamical symmetry. The spherical-like γ-softness is not related to the classical O(6) dynamical symmetry. The transitional behaviors of B(E2) values of the low-lying levels, and quadrupole moment of the 2+ 1 state are also discussed. Spherical-like γ-softness can be used to explain the low-lying spectra and B(E2) values in 110 Cd normal states.

The unusually low value of the ratio B 4/2 = B(E2; 4 + 1 → 2 + 1 )/B(E2; 2 + 1 → 0 + 1 ) along the yrast band is described in the interacting boson model-1. Two three-body interactions with SU (3) symmetry are additionally introduced into the usual Hamiltonian describing the transitional behaviors from the spherical vibration to the ellipsoidal rotation. In the SU (3) limit, the energy of the 4 + state in the irrep (2N −8, 4) can be lower than the one of the 4 + state in the irrep (2N, 0), which causes the anomaly.

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