The ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}({}_{}{}^2{}_{}{}^{}\mathrm{C},p){}_{}{}^{23}{}_{}{}^{}\mathrm{Na}$ reaction has been used to study the reaction mechanism in the ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ + ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ system through the measurement of proton angular distributions. Angular distributions of protons emitted to nearly 70 states in ${}_{}{}^{23}{}_{}{}^{}\mathrm{Na}$ have been measured for three beam energies 29.5, 30.0, and 30.5 MeV. The energy region has been chosen as one not containing any "resonance" observed so far in this channel. Excitation functions for the energy range 29.0-30.8 MeV, with a $\Delta E=100\mathrm{}$ keV step, have been measured at a laboratory angle of 30°. Angular distributions for all incident energies exhibit strong structure which is preserved in averaged angular distributions. Comparison with the Hauser-Feshbach model is presented to show the deviation of the measured quantities from the statistical predictions. As the direct transfer of 11 nucleons and preequilibrium emission do not seem possible due to the small energy involved, the existence of another reaction mechanism is suggested.

[NUCLEAR REACTIONS ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}({}_{}{}^{12}{}_{}{}^{}\mathrm{C},p){}_{}{}^{23}{}_{}{}^{}\mathrm{Na}$, $E_{\mathrm{lab}}=29.5,30.0,30.5\mathrm{}$ Mev. Measured $\sigma (E_p,\theta )$. Hauser-Feshbach calculations.]

• Received 22 December 1980

DOI:https://doi.org/10.1103/PhysRevC.24.111