Intrinsic and inhomogeneous damping of giant dipole resonance in hot nuclei

11h -Salle des Séminaires du GANIL

Giant dipole resonance (GDR), built on excited states, provides a clean tool to study the damping of the collective vibration in hot rotating nuclei. The inhomogeneous damping arises due to the splitting of the GDR energy in deformed nuclei. The thermal shape fluctuation (TSF) in hot nuclei makes the GDR width increase with temperature (T) and angular momentum. The intrinsic damping arises due to the collisional energy loss of the particle-hole pair comprising the GDR with the other nucleons. The evaporation widths of the compound nuclear states also contribute to the observed GDR width, particularly, at high temperature.

Although all the contributions should be present in deciding the T-dependence of the GDR width, there is as yet no clear demonstration of the necessity of the T-dependent intrinsic damping beyond the contribution from the inhomogeneous damping. In the present talk, a recent experiment at the Pelletron Linac Facility (PLF), Mumbai, will be described. The T and J dependence of the extracted GDR width will be compared with the TSF calculation. The necessity of the inclusion of the T-dependent intrinsic damping will be demonstrated.