Measurements of angular distributions for inelastic scattering in the ${}_{}{}^{11}{}_{}{}^{}\mathrm{B}$${+}^{12}$C system with excitation of the $2^{+}$ (4.44 MeV) level of ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ and 1/$2^{\mathrm{-}}$ (2.12 MeV) and 5/$2^{\mathrm{-}}$ (4.44 MeV) levels of ${}_{}{}^{11}{}_{}{}^{}\mathrm{B}$ nuclei were performed in the energy range from 15 to 40 MeV c.m. in ≃2.5 MeV steps in broad angular regions up to about 170° c.m. The cross section at forward angles was well described in the distorted-wave Born approximation by collective model with energy-independent deformation length. The rise of cross section at the backward angles was explained as inelastic proton transfer. The extracted values of the proton spectroscopic factors for the excited nuclei ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}_{4.44}^{\mathrm{*}}{}_{}{}^{}$ and ${}_{}{}^{11}{}_{}{}^{}\mathrm{B}_{2.12}^{\mathrm{*}}{}_{}{}^{}$ are energy independent in contradiction to the previously found energy-dependent spectroscopic factor for ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}_{\mathrm{g}.\mathrm{s}.\mathrm{}}^{}{}_{}{}^{}$=p${+}^{11}$${\mathrm{B}}_{\mathrm{g}.\mathrm{s}.\mathrm{}}$.

• Received 21 March 1991

DOI:https://doi.org/10.1103/PhysRevC.44.2053