Evolution of collectivity to very high spins in ¹⁶⁰Yb

Lifetimes of ¹⁶⁰Yb yrast states at high rotational frequencies have been measured by the Doppler broadened line shape technique. Excited states in ¹⁶⁰Yb were populated by the reaction ¹²⁰Sn(⁴⁴Ca,4n)¹⁶⁰Yb 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⁺ to 32⁺ yrast states led to values of the transition quadrupole moments similar to those obtained for the lower members (Latin small letter h with stroke)ω≤0.29 MeV) of the ground band in previous recoil-distance measurements. The trend of reducing Q₁ values found for the I=34⁺ and 36⁺ states are suggestive of band termination. The results are discussed in the light of current theoretical predictions.