Pre-equilibrium γ-ray emission induced in the 40Ca+48Ca system at 10 MeV/nucleon and isospin equilibration processes
Abstract
In the present paper we have studied γ-ray emission in coincidence with charged particles measured in binary processes for the collisions 40Ca+48Ca, 46Ti at 10 MeV/nucleon. The comparison between γ-ray yields, obtained under identical conditions on the charged particles detected in coincidence, shows an extra yield of around 15 MeV for the 40Ca+48Ca collision. The analysis of the γ-charged fragment coincidence events, along with the study performed with the dynamical model CoMD-II, explains this effect as the result of a giant dipole resonance emission from the intermediate system, characterized by a high degree of coherence. The performed study aims to establish a link among pre-equilibrium γ-ray emission, initial charge/mass ratio memory effects in the intermediate system for the 40Ca+48Ca system at short time, and the achievement of a substantial charge/mass ratio or isospin equilibration of the primary fragments formed at longer time. Moreover, the presence of a remarkable extra yield in a restricted range of the γ-ray spectra suggests that this equilibration process evolves through a quasiresonant mechanism.
- Publication:
-
Physical Review C
- Pub Date:
- December 2005
- DOI:
- 10.1103/PhysRevC.72.064608
- Bibcode:
- 2005PhRvC..72f4608P
- Keywords:
-
- 24.10.-i;
- 24.60.-k;
- 24.30.Cz;
- 21.30.Fe;
- Nuclear reaction models and methods;
- Statistical theory and fluctuations;
- Giant resonances;
- Forces in hadronic systems and effective interactions