Abstract
The and reactions have been studied using the Glasgow photon tagging spectrometer at the Mainz MAMI electron microtron for MeV over a kinematic range which extends well beyond the approximately back-to-back detector arrangements of previous work. For the general trends of the missing energy distributions are reproduced over a wide range of kinematics and photon energies by the theory developed by the Valencia group. The corresponding channel is overestimated by a factor of ∼3. Detailed comparisons of the experimental data with a Monte Carlo simulation of the direct knockout process provide the first evidence above the resonance for direct knockout and show that this process dominates the reaction at low missing energies up to MeV. The reaction is somewhat less well described by the Monte Carlo simulation. A possible explanation of the observed discrepancies within a direct framework is presented. At high recoil momenta both reaction channels exhibit an excess yield compared to the Monte Carlo prediction of direct knockout. The excess yield in this region is compared with the predicted effects of short-range correlations and with the predicted contributions due to other reaction mechanisms.
- Received 23 November 1999
DOI:https://doi.org/10.1103/PhysRevC.62.014616
©2000 American Physical Society