No abstract

We measured the 12 C(e,e ′ p) cross section as a function of missing energy in parallel kinematics for (q, ω) = (970 MeV/c, 330 MeV) and (990 MeV/c, 475 MeV). At ω = 475 MeV, at the maximum of the quasielastic peak, there is a large continuum (Em > 50 MeV) cross section extending out to the deepest missing energy measured, amounting to almost 50% of the measured cross section. The ratio of data to DWIA calculation is 0.4 for both the p-and s-shells. At ω = 330 MeV, well below the maximum of the quasielastic peak, the continuum cross section is much smaller and the ratio of data to DWIA calculation is 0.85 for the p-shell and 1.0 for the s-shell. We infer that one or more mechanisms that increase with ω transform some of the single-nucleon-knockout into multinucleon knockout, decreasing the valence knockout cross section and increasing the continuum cross section.

We have measured missing-energy spectra for the reaction n C(e,e'p) in the quasielastic region in parallel kinematics at momentum transfers q of 585, 775, and 827 MeV/c. We observed l p and ] s single-proton knockout peaks and large broad strength attributed to multinucleon knockout. We saw no increase in strength at pion threshold. The ratio of single-particle knockout to a distorted-wave impulse-approximation calculation is approximately constant with q. Multinucleon knockout is 25%-40% of the total cross section; it increases with q. This quasielastic non-single-nucleon knockout is much stronger than previously observed.

No abstract