Search for particle-bound 26O and 28F in p-stripping reactions

We have searched for particle-bound 26O and 28F isotopes in the reaction products of secondary 27F and 29Ne beams, respectively. No events have been observed. Upper limits of 3.3 mb and 1.2 mb for the respective production cross sections of 26O and 28F by one p-stripping reactions are established. Since in the case of 28F, this upper limit is sufficiently small compared to common estimates, we conclude that 28F is most likely unbound. For the case of 26O, our result is not statistically significant, thus, the question cannot be answered whether 26O is a particle-unbound nucleus or not