Lifetime measurements of excited states in ¹⁶³W and the implications for the anomalous B(E2) ratios in transitional nuclei

This letter reports lifetime measurements of excited states in the odd-N nucleus 163W using the recoil-distance Doppler shift method to probe the core polarising effect of the i13/2 neutron orbital on the underlying soft triaxial even-even core. The ratio B(E2:21/2⁺ → 17/2⁺)/B(E2:17/2⁺ → 13/2⁺) is consistent with the predictions of the collective rotational model. The deduced B(E2) values provide insights into the validity of collective model predictions for heavy transitional nuclei and a geometric origin for the anomalous B(E2) ratios observed in nearby even-even nuclei is proposed.