Reaction Mechanisms inFe56(p,p′)from 5 to 6 MeV

Proton angular distributions and spin-flip angular correlations have been measured as absolute cross sections for inelastic scattering of 4.96-, 5.58-, and 5.88-MeV protons to the first excited ($2^{+}$) state at 0.847 MeV in ${}_{}{}^{56}{}_{}{}^{}\mathrm{Fe}$. The spin-flip measurements involve directional correlation of the 0.847-MeV $\gamma$ rays, detected along a perpendicular to the reaction plane, with the inelastic protons observed at angles from 30° to 150° in the reaction plane. The spin-flip probability was determined for the three energies studied. The measured cross sections are compared with the predictions of the statistical model and the direct-interaction model. The compound-nucleus mechanism appears to dominate the reaction in this energy range. The statistical-model predictions, which are based on optical-model parameters obtained at somewhat higher energies, give the correct shape and order of magnitude, but fail to fit simultaneously both the angular distributions and the spin-flip correlation data.