A search for the neutron-unbound nucleus $^{ 21}$C was performed via the single proton removal reaction from a beam of 22 N at 68 MeV/u. Neutrons were detected with the Modular Neutron Array (MoNA) in coincidence with $^{ 20}$C fragments. No evidence for a low-lying state was found, and the reconstructed $^{ 20}$C+n decay energy spectrum could be described with an s-wave line shape with a scattering length limit of |as| < 2.8 fm, consistent with shell model predictions. A comparison with a renormalized zero-range three-body model suggests that $^{ 22}$C is bound by less than 70 keV.
Categories: nucl-ex