Spectroscopic factors measured in inclusive proton-knockout reactions on 8B and 9C at intermediate energies -: art. no. 064301

The knockout of protons from B-8 and C-9 on a carbon target has been studied at average energies of 76 and 78 MeV/nucleon, respectively, with beams from the A1900 fragment separator incident on a stack of silicon detectors. The following cross sections were obtained: sigma(-1p)(B-8-->Be-7) = 130(11) mb, sigma(-1p)(C-9-->B-8) = 54(4) mb, and sigma(-2p)(C-9-->Be-7) = 98(7) mb. The results are discussed within the framework of an eikonal approach and compared with measurements performed at higher energies. From this analysis, a consistent picture emerges that gives evidence for the validity of the eikonal approach at energies below 100 MeV/nucleon. Knockout reactions at intermediate energy can thus be used to deduce absolute shell occupancies. We find the spectroscopic factors to be reduced by R-s of 0.86(7) and 0.82(6) for B-8 and C-9, respectively, relative to shell-model predictions. The C-9 result provides an accurate measurement of the asymptotic normalization coefficient of 1.27(10) fm(-1). A new technique is reported for determining separately the contributions from stripping and diffractive breakup.