Evidence for coexisting prolate and near-oblate shapes at high spin in 125 Cs

Excited states in the odd-proton nucleus 125Cs were investigated by means of in-beam γ -ray spectroscopy. The πg7/2 band is observed to fork into a ΔI = 1 coupled band and a ΔI = 2 decoupled band at high spins. To assign the possible configurations of these two bands, experimental B(M1)/B(E2) ratios and signature splittings have been evaluated for the ΔI = 1 band, and calculations based on the geometrical model, cranked shell model and total Routhian surfaces model have been performed. They are suggested to be a near-oblate band built on the (πg7/2/d5/2) ⊗ (νh11/2)2 configuration and a prolate band built on the πg7/2 ⊗ (πh11/2)2 configuration, respectively.

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