Status of the study of the Giant Dipole Resonance as a probe of the structure of hot nuclei

Recent advances concerning the study of the Giant Dipole Resonance in hot rotating nuclei are discussed. The γ-decay of the GDR built on excited states as a function of nuclear temperature and angular momentum is reviewed for the two mass regions, A∼110 and A∼170, characterized by different nuclear shapes. The data show the different effects of temperature and angular momentum. A new generation of experiments has been undertaken in which particular decay cascades of the compound nucleus containing high-energy γ-rays are selected. Two measurements of this type are presented. One was made to study of the GDR in 194Hg and to test in detail the hypothesis of thermalization and the other aimed at searching the GDR in a superdeformed nucleus