Collective bands in the triaxial nucleus 124Xe Original Research Article

The nonyrast states of View the MathML source have been investigated with the View the MathML source reaction by means of in-beam γ-spectroscopy using a setup of 6 Compton-suppressed high-purity-germanium (HPGe) detectors. More than 65 new transitions, establishing 34 new levels, were observed. γγ-angular correlations were analyzed to assign spins and parities to the low-lying states, and to determine the multipolarities of the γ-transitions. In addition, the γ-excitation-function method was used for spin assignments. With these methods 10 (18) spin and parity assignments were made (some of them tentative) and 7 multipole mixing ratios could be determined. The excitation energies and B(E2) ratios of low-lying states are compared with predictions of the sd-IBM-1, giving rise to the identification of a 0+ state with O(6) quantum number σ=N−2. Quadrupole shape invariants for the ground state and effective deformation parameters are calculated, showing an admixture of U(5) symmetry to the ground-state wave function.