WARM NUCLEI: NUCLEAR STRUCTURE EFFECTS ON THE ORDER-TO-CHAOS TRANSITION REGION.

The γ-decay from the warm rotation in the transition region between order and chaos is studied in the superdeformed (SD) nuclei ¹⁵¹Tb and ¹⁹⁶Pb, using the EUROBALL IV array. A number of observables, testing the decay dynamics in the SD well, are compared with predictions from a Monte Carlo simulation of the γ-decay based on microscopic calculations of discrete levels and decay probabilities. Agreement with the data is found only assuming an enhancement of the B(E1) strength around 1 MeV by a factor of 10-100, which is consistent with the evidence for octupole vibrations in both mass regions. The work shows the relevance of γ-spectroscopy in the order-to-chaos regime to highlight specific nuclear structure effects. [ABSTRACT FROM AUTHOR]