Multiphonon giant resonances: Experimental status and perspectives

Abstract

Recently, decisive progress has been made in the search for multiphonon states built with giant resonances. This paper will first focus on the different probes used to excite multiphonon states, and the experimental methods used to characterize these states. Several examples of experiments where the two-phonon giant resonance has been observed are described. The possibility of signing two-phonon strength through its direct decay by particle emission is then discussed in detail, and the results of the ongoing experimental program at GANIL are presented. Finally, the potential of different methods for the future observation of three-phonon states is briefly examined.