A HIGH-RESOLUTION STUDY OF THE C-12(GAMMA,P) REACTION WITH 49-78.5 MEV TAGGED PHOTONS

We present tabulated cross-section measurements for the reaction 12C(γ, p) leading to resolved, low-lying, excited states of 11B. The measurements were obtained using tagged photons of 49-78.5 MeV and for mean laboratory proton emission angles from 65° to 115°. The proton excitation energy spectra are dominated by the ground state ( 3 2-), 2.13 MeV ( 1 2-), 5.02 MeV ( 3 2-) and doublet ( 7 2-, 1 2+) states of 11B. No evidence is found for the population of the 4.45 MeV ( 5 2-) state. Our analysis demonstrates that both the ground-state and excited-state cross-section data scale with momentum mismatch. The data are qualitatively discussed within the context of the existing (e, e'p) data and direct knockout and quasideuteron models. A consistent and quantitative understanding of the data will require more sophisticated models than are currently available. © 1990.