Pre-equilibrium effects of the hot nuclei de-excitation via GDR emission - theoretical approach

TL;DR

This paper investigates how pre-equilibrium particle emission influences the Giant Dipole Resonance strength function in hot nuclei, using a theoretical approach that combines dynamical models and statistical descriptions.

Contribution

It introduces a theoretical analysis of pre-equilibrium effects on GDR strength functions in hot nuclei, integrating the Thermal Shape Fluctuation Model with dynamical evolution insights.

Findings

Pre-equilibrium emission affects GDR strength distribution.

Theoretical modeling links emission processes to GDR properties.

Results suggest modifications to GDR observables due to pre-equilibrium effects.

Abstract

The hot rotating nuclei could be formed in the complete and incomplete fusion reaction of two heavy ions. At low bombarding energies the reaction goes via compound nucleus formation and subsequent evaporation of charged particles, neutrons and $\gamma$-rays. However, with increasing the energy of the projectile, the emission of particles during the equilibration process becomes more and more probable. This effect can be estimated by the Heavy-Ion Phase-Space Exploration (HIPSE) code which describes the production of clusters of various size from nucleons initially in the target or projectile. This dynamic evolution finalizes with the compound nuclei, quasi-fission or multi-fragmentation products. The hot rotating nuclei produced in fusion reaction can de-excitate by evaporation of particles and emission of $\gamma$-rays from the Giant Dipole Resonance, or by fission into two fragments. These processes, evaporation and fission, are described within statistical codes such as GEMINI++ or in dynamical approaches by solving the transport equations of Langevin type. In the present article we will concentrate on the possible effect of the pre-equilibrium emission on the strength function of the effective Giant Dipole Resonance, which can be described within Thermal Shape Fluctuation Model (TSFM) approach.