Abstract Lifetimes of excited states in ^162 162 Dy were measured using the (n, n’ γ) reaction with the Doppler-Shift Attenuation Method (DSAM) at the University of Kentucky’s Accelerator Laboratory. A total of eighteen level lifetimes were obtained, including eleven negative-parity states, seven of which are new. These measurements significantly expand the experimental database of transition probabilities for negative-parity bands in the well-deformed rare earth region of nuclei. The extracted B (E 1) and B (E 2) values reveal enhanced interband E1 (10^-3 10 - 3 or 10^-4 10 - 4) W. u. and E2 strengths (several W. u. ) between negative- and positive parity bands, particularly for the K"Equation missing" bands decaying to the the K ^ =2^+ π = 2 γ + band, consistent with signatures of octupole-quadrupole coupling. In contrast, the K ^ =0^-₁ π = 0 1 - and K ^ =1^-₃ π = 1 3 - bands, which exhibit strong E1 transitions to the ground state band, are indicative of octupole-vibrational excitations built on the deformed ground state. Comparison of transition rates with Alaga rules supports this interpretation and distinguishes collective excitations from likely quasi-particle states. These new results establish ^162 162 Dy as the most extensively characterized rare-earth nucleus for negative parity lifetimes and provide critical experimental benchmarks for theoretical models.
Aprahamian et al. (Fri,) studied this question.