Evolution of collectivity to very high spins in 160Yb.

Lifetimes of {sup 160}Yb yrast states at high rotational frequencies have been measured by the Doppler broadened line shape technique. Excited states in {sup 160}Yb were populated by the reaction {sup 120}Sn({sup 44}Ca,4{ital n}){sup 160}Yb at a beam energy of 200 MeV and the experimental measurements were carried out in the coincidence mode with an array of Compton-suppressed germanium detectors. The results for the 24{sup +} to 32{sup +} yrast states led to values of the transition quadrupole moments similar to those obtained for the lower members ({h_bar}{omega}{le}0.29 MeV) of the ground band in previous recoil-distance measurements. The trend of reducing {ital Q}{sub {ital t}} values found for the {ital I}=34{sup +} and 36{sup +} states are suggestive of band termination. The results are discussed in the light of current theoretical predictions. {copyright} {ital 1996 The American Physical Society.}