First experimental test of X(5) critical-point symmetry in the A~130 mass region: Low-spin states and the collective structure of ¹³⁰Ce

Excited, low-spin states in ¹³⁰Ce are populated in the β⁺/ε decay of ¹³⁰Pr and studied through off-beam γ-ray spectroscopy at the Yale moving tape collector. New coincidence data lead to the construction of a substantially revised level scheme. The low-lying states of ¹³⁰Ce are compared with the predictions of the X(5) critical-point model and the X(5)-β⁴ model, and the latter is found to give better agreement with the data in terms of energies. Discrepancies in the relative B(E2) values in ¹³⁰Ce and the geometrical models suggest that the γ degree of freedom may play an important role in this mass region.