New structures in the continuum of 15C populated by two-neutron transfer

The 13C(18O, 16O)15C reaction has been studied at 84 MeV incident energy. The ejectiles have been detected at forward angles and 15C excitation energy spectra have been obtained up to about 20 MeV. Several known bound and resonant states of 15C have been identified together with two unknown structures at 10.5 MeV (FWHM=2.5 MeV) and 13.6 MeV (FWHM=2.5 MeV). Calculations based on the removal of two uncorrelated neutrons from the projectile describe a significant part of the continuum observed in the energy spectra. In particular the structure at 10.5 MeV is dominated by a resonance of 15C near the C13+n+n threshold. Similar structures are found in nearby nuclei such as 14C and 11Be.