The present article is the third out of three on a study of the 40 Ca(e, e x) reaction discussing the role of direct and statistical contributions to the decay of the observed giant resonance strengths. The proton and α decay modes leading to low-lying final states in 36 Ar and 39 K were investigated. The branching ratios for the p 0 , p 123 , α 0 and α 1 channels are compared to statistical model calculations.
In the excitation region of dominant isoscalar E2 strength (E x = 12-18 MeV) good agreement is observed. Model predictions of direct E2 decay for the (α 0 + α 1 )/(p 0 + p 1 ) ratio describe the data poorly. In the isovector E1 excitation region large excess strength is found in the population of lowlying states in 39 K. A fluctuation analysis shows the direct contributions to the p 0 , p 1 channels to be 85%. The presence of preequilibrium components is indicated by the significant nonstatistical decay to the p 3 level which has a dominant 'phonon ⊗ hole' structure. Cross correlations reveal no significant branching between the different channels. The correlations between different electron scattering angles in the p 0 , p 1 and p 3 decay result in an interaction radius compatible with the whole nucleus acting as an emitting source.