Search for particle-bound 26-O and 28-F in p-stripping reactions
  We have searched for particle-bound 26-O and 28-F isotopes in the reaction products of secondary 27-F and 29-Ne beams, respectively. No events have been observed. Upper limits for the respective production cross sections by one-p-stripping reactions are established under the assumption that 26-O and 28-F are particle bound. Since the experimental upper limits are much lower than common estimates we conclude that neither 26-O nor 28-F are likely particle bound. 
A. Schiller, T. Baumann, J. Dietrich, S. Kaiser, W. Peters, M.   Thoennessen