Properties and applications of hot giant resonances

Recent advances in the study of giant resonances in hot nuclei are summarized. Determination of the giant dipole resonance (GDR) width as a function, separately, of the nuclear temperature and angular momentum supports the notion that the growth of the width and its saturation at high angular momentum, result from the sampling of the potential surface. The temperature limit of the coherent GDR vibration has been established to be T∼4.5 MeV, where the life time of the compound nucleus approaches the time of one full vibration. First attempts to observe the giant isoscalar monopole resonance in hot nuclei through internal pair decay are promising but still lack sensitivity to one monopole sum rule strength. The use of the GDR as a clock of the fission process shows the fission motion to be highly damped at even moderate temperatures, with a definite threshold energy and then rapid increase of the linear friction coefficient. (author)