Prolate-oblate asymmetric shape phase transition in the interacting boson model with SU(3) higher-order interactions

Prolate-oblate shape transitions and O(6) symmetry in even–even nuclei: a theoretical overview

“…The IBM calculations of [105], in which higher-order interactions are included, predict oblate shapes at N = 114-120 (see figure 9 of [105]). The IBM calculations of [106], in which again higher-order interactions are included, are also compatible with oblate shapes at N = 114-120 (see figure 15 of [106] for the experimental data of the…”

“…A further important step has been taken in 2023 in [106], in which a vibrational term, n d ˆ, is added to the Hamiltonian containing the second-order and third-order Casimir operators of SU (3). The prolate and oblate shapes are asymmetric, with the prolate shape exhibiting deformation on average twice that of the oblate shape.…”

“…has been suggested as an order parameter, since it acquires values close to unity on the prolate side, on which the β and γ bands are lying close to each other, while it becomes much larger on the oblate side (see figure 15 of [106]), since on this side the bandhead of the γ-band, + 2 2 , falls below the bandhead of the β-band, + 0 2 [106].…”