Neutron knockout of 12Be populating neutron-unbound states in 11Be
  Neutron-unbound resonant states of 11Be were populated in neutron knock-out reactions from 12Be and identified by 10Be-n coincidence measurements. A resonance in the decay-energy spectrum at 80(2) keV was attributed to a highly excited unbound state in 11Be at 3.949(2) MeV decaying to the 2+ excited state in 10Be. A knockout cross section of 15(3) mb was inferred for this 3.949(2) MeV state suggesting a spectroscopic factor near unity for this 0p3/2- level, consistent with the detailed shell model calculations. 
William A. Peters, T. Baumann, B. A. Brown, J. Brown, P. A. DeYoung,   J. E. Finck, N. Frank, K. L. Jones, J.-L. Lecouey, B....
nucl-ex