One-neutron removal reactions of 18C and 19C on a proton target

We have studied the one-neutron removal reactions of 18C at 81 MeV/nucleon and 19C at 68 MeV/nucleon on a liquid hydrogen target. Transverse-momentum distributions of the core fragments 17C and 18C, and their partial cross sections, are measured using coincidences with the γ rays. These are compared to theoretical calculations based on the continuum-discretized coupled-channels (CDCC) method. We have found that the transverse-momentum distributions of 17C are well described by the CDCC calculations, and the agreement provides evidence for the spin-parity assignments of Jπ=1/2+ for the 0.21-MeV state and Jπ=5/2+ for the 0.33-MeV state in 17C. The Jπ=(2,3)+ assignment for the 4.0-MeV state in 18C is obtained for the first time based on the momentum distribution of 18C. The measured partial cross sections are consistent with the CDCC calculations combined with shell-model spectroscopic factors. The present study demonstrates that the transverse-momentum distribution obtained in a one-neutron removal reaction on a proton target is as useful as the conventional longitudinal-momentum distribution measured with the heavier Be or C targets for determining the orbital angular momentum of a removed neutron