High-resolution study of the C 12 ( γ , p γ ' ) B 11 reaction using a HpGe detector to resolve excited states of B 11 through the observation of their γ-ray decays

Relative populations of states in 11B following the 12C(,p)11B reaction have been measured with high resolution using a 70% HpGe detector to observe decay rays from the residual nucleus. The triplet of states near 7 MeV in 11B are resolved and the measured populations compared to previous data. The analysis includes a consideration of -proton angular correlations, which was not made in the previous measurement. The new and previous results corrected for angular correlation effects agree reasonably well with calculations that include one- and two-body nuclear currents, pion exchange, and currents, under the assumption that the photons are mainly absorbed on exchanged pions.