Damping of Nuclear Rotational Motion at Modest Temperatures

Abstract

There is mounting evidence that the nuclear rotational motion is damped at modest (≅0.5 MeV) temperatures, which reduces correlations between the energies of $\gamma$ rays emitted in a rotational cascade. We observe such reduction to be strongest at the highest spins and to be larger than previously thought. Preliminary calculation shows that shape fluctuations are most likely responsible for the increased size.