Search for the (15)Be ground state
A two-proton knockout reaction from a (17)C beam at 55 MeV/u was used to produce the unbound nucleus (15)Be. No significant number of events were observed for the decay of (15)Be into a neutron and a (14)Be fragment. An upper limit for the (14)Be production cross section of 0.079 +/- 0.038 mb was extracted, which is more than an order of magnitude smaller than the predicted two-proton knockout reaction cross section. Based on these results we conclude that any populated states in (15)Be decay through three sequential neutron decays into (12)Be, via the unbound first excited state of (14)Be. Therefore, these states in (15)Be must be neutron unbound by more than 1.54 MeV, which is the location of the first excited 2(+) state in (14)Be.
Published in: Physical Review C, Volume 84, Issue 4, October 12, 2011, pages 044309-. Copyright © 2011 American Physical Society, College Park, MD. The final published version is available at: http://dx.doi.org/10.1103/PhysRevC.84.044309