Excitation and decay of giant-resonances in the CA-40(E,E'X) reaction

The Ca-40(e,e'x) reaction has been investigated for excitation energies between 8 and 26 MeV and momentum transfers from 0.25 to 0.66 fm-1 at the continuous-wave electron accelerators MAMI at Mainz and S-DALINAC at Darmstadt. A multipole decomposition of the cross sections reveals strongly fragmented E2 (plus E0) strength around 14 and 17 MeV in contrast to all theoretical predictions. Angular correlations of proton decay are described over the entire energy range by a continuum random-phase-approximation approach. A comparison of the branching ratios to statistical model calculations provides information on the dominant damping mechanism

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. © 1994.Articl