Collective transitions at high level density

It has been assumed that highly excited collective bands, more or less parallel to the yrast line, are important for the gamma deexcitation of rotational nuclei formed in heavy-ion reactions. This paper draws attention to the possibility that the in-band decay of any given state may be spread over a broad spectrum and discusses the implications for the cascade process. A simple model, where bands are generated by coherent matrix motion in the Gaussian orthogonal ensemble, indicates how the spreading width may depend on the fundamental nature of nuclear level structure.NUCLEAR STRUCTURE Model for collective bands at high level density. Spreading of in-band transitions and consequences for quasicontinuum gamma cascades at very high spin.