Average Lifetimes of Collective Transitions in the Spin-(30-50) Region

Abstract

A method is developed to determine average lifetimes of continuum gamma rays following heavy-ion compound-nucleus reactions. The resulting enhancement factors for $E2$ transitions depopulating states in the spin-(30-50) regions are of the same order of magnitude as for ground-state rotational bands of deformed nuclei. This shows for the first time that these high-spin states decay through strongly collective bands.