Preequilibrium proton decay in ⁴°Ca

The proton spectra of the giant quadrupole resonance decay in {sup 40}Ca is analyzed. The decay mechanism of this excitation is studied by the inclusion of the semidirect, preequilibrium, and statistical modes through the chaining evolution of the particle-hole configurations. Strong evidence for the contribution of preequilibrium decay of the giant resonance is established. {copyright} {ital 1997} {ital The American Physical Society}