OBSERVATION OF 2-STEP PROCESSES IN THE QUASI-ELASTIC REACTION C-12(E,E'P)B-11

The contribution of two-step processes in the reaction C-12(e, e'p)B-11 has been studied under quasi-elastic conditions. Cross sections were measured for the transitions to the 5/2- state at an excitation energy of 4.445 MeV and the (7/2-, 1/2+)-doublet at 6.767 MeV in the missing momentum range between 140 MeV/c and 220 MeV/c. The excitation of the 5/2- states, which was never observed before in (e, e'p) experiments on C-12, can be quantitatively described as being due to a two-step process. A good description of the excitation of the (7/2-, 1/2+) doublet is obtained with a coupled-channels calculation including both direct knockout and two-step contributions.