Experimental Test of Statistical-Model Approximations WhenΓD>1

Cross sections have been measured for the reaction ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}(p,\alpha ){}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$ to the ground and first six excited states of the residual nucleus at seven angles and in 30-keV steps over the proton laboratory energy region of 8-10 MeV. Average cross sections were calculated using formulas dependent on Hauser-Feshbach-model assumptions. Correlation functions for the statistical fluctuation of cross sections with energy were examined. The Hauser-Feshbach model and the Ericson fluctuation theory have been found to be adequate to describe the average cross sections and cross-section fluctuations for both open and partially open exit channels.