Observation of a low-lying neutron-unbound state in 19C

Proton removal reactions from a secondary 22N beam were utilized to populate unbound states in neutron-rich carbon isotopes. Neutrons were measured with the Modular Neutron Array (MoNA) in coincidence with carbon fragments. A resonance with a decay energy of 76(14) keV was observed in the system C18+n corresponding to a state in 19C at an excitation energy of 653(95) keV. This resonance could correspond to the first 5/2+5/2+ state which was recently speculated to be unbound in order to describe 1n and 2n removal cross section measurements from 20C.