Giant Dipole Resonance In Hot Nuclei Research Articles

Theoretical description of the giant-dipole resonance in hot nuclei

Theoretical models accounting for the effects of large-amplitude thermal fluctuations of the nuclear surface on the observations of the giant-dipole resonance in hot nuclei are described and compared with recent experimental data.

Effects of angular momentum projection on the nuclear partition function and the observation of the giant-dipole resonance in hot nuclei

Procedures for projecting the angular momentum in a model describing a hot nucleus that takes into account large-amplitude quadrupole fluctuations are discussed. Particular attention is paid to the effect angular momentum projection has on the observables associated with the γ-decay of the giant-dipole resonance (GDR). We also elaborate on which of the different projection methods provides the best overall description of the GDR, including angular distributions. The main consequence of angular momentum projection is the appearance of an effective volume element in the integrals associated with the thermal average of the physical observables. This effective volume element is controlled by the value of the moments of inertia of the system. In the limit of rigid-body moments of inertia, the effective volume element is found to differ only slightly from the volume element associated with the normalization of the five-dimensional quadrupole oscillator wavefunction in the β, γ, and Ω space, namely D[α] = β 4 dβ sin(3γ) dγdΩ . In the limit of irrotational flow moments of inertia, the leading behavior in the β degree of freedom is D[ α] ∝ β dβ.

Future microscopic developments for the GDR in hot nuclei

The application of auxiliary-field Monte Carlo techniques to the giant-dipole resonance (GDR) in hot nuclei is described. The method allows for a fully microscopic description of the GDR that includes all effects that were previously modeled macroscopically. Preliminary results obtained with a schematic interaction are presented for 16O and 20Ne using the 0p — 1s0d — 0ƒ 7 2 shell-model configuration space. The difficulties inherent in the method are detailed, and suggestions for future work are given.