Excitation and decay of electric giant resonances in the 40Ca(e,e'x) and 40Ca(p,p'x) reactions

The excitation and decay of electric giant resonances in 40Ca in the excitation energy range Ex = 8 - 26 MeV was investigated with the (e,e'x; x=p,α) reaction for momentum transfers from 0.25 to 0.66 fm-1. The angular correlations of proton decay into low-lying states of 39K are successfully described by a RPA continuum approach emphasizing the importance of multistep contributions. The dominant reaction mechanism is extracted from a comparison of the branching ratios into resolved final channels with statistical model calculations and a fluctuation analysis. First results of a 40Ca(p,p'x) experiment covering the same 40Ca excitation region permit insight into the fine structure of the GQR and its decay. (orig.)