Structure of even-even Dy nuclei in the interacting boson model with two-quasiparticle states

The energy levels of g.s. bands, β bands, and γ bands of ${}_{}{}^{154\mathrm{-}162}{}_{}{}^{}\mathrm{Dy}$ isotopes are studied in the model of the traditional interacting boson approximation, allowing one boson to break and form a quasiparticle pair. The two quasiparticles are allowed to excite to the $i_{13/2}$ and $h_{11/2}$ orbitals. It was found that the energy levels of the g.s., β, and γ bands of even-even Dy nuclei can be reproduced very well. The backbends of the moment of inertia can also be reasonably described. The yrast B(E2) values are also calculated and compared with the experimental data.