Spectroscopy of ^17 C Above the Neutron Separation Energy

Spectroscopy of an unbound nucleus ^17 C was performed using the SAMURAI spectrometer at RIBF of RIKEN. Six resonances were observed for the ^16 C+n system with relative energies of 0.52, 0.77, 1.36, 1.91, 2.22 and 3.20 MeV. The excitation energies ( E_x ) of the observed resonances were deduced, by taking into account the states of the ^16 C fragments identified by coincident γ rays, as E_x =(3.02), 1.51, (3.86), 2.65, (4.72) and 3.94 MeV. The orbital angular momenta of the two observed states in ^17 C at E_x =2.65 and 3.94 MeV were determined as 1 by comparing parallel momentum distributions with theoretical predictions.