Radiative-capture studies of the giant dipole resonance. Gamma-ray yields from capture of protons and alpha-particles give finer details than studies of gamma-ray absorption

The data on radiative capture through the giant resonance have led to a model in which the capture is pictured as proceeding through a single broad (and therefore short-lived) state that can be called the giant-resonance state. This state is the one formed directly upon capture of a proton, and hence most of the capture radiation is emitted quickly in the direct-interaction mode. Some of the energy that is contained in the giant-resonance state is shared with the more-complicated states of the compound nucleus (that is, with states having many excited nucleons). This sharing, in turn, gives rise to the fine structure that is observed within the giant-resonance envelope. The constant angular distributions that are observed throughout the giant-resonance region support the single-state picture of the giant resonance.