The energy-sharing distribution at a coplanar symmetric quasifree angle pair has been measured for the ${}^{12}\mathrm{C}(\alpha ,2\mathrm{}\alpha {)}^8\mathrm{Be}(\mathrm{g}.\mathrm{s}.\mathrm{})$ reaction at an incident energy of 200 MeV. The measured knockout cross sections are compared with distorted wave impulse approximation calculations. Extracted spectroscopic factors are found to be in reasonable agreement with a theoretical prediction and results from $(p,p\alpha )$ studies. The present results indicate a transition in the dynamics of this reaction in the incident energy region 140–200 MeV.

• Received 9 December 1998

DOI:https://doi.org/10.1103/PhysRevC.59.2097