C12(n,p)12B reaction at 56, 60, and 65 MeV

The ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$(n,p${)}^{12}$B reaction has been studied at 60 and 65 MeV. Cross sections for the $1^{+}$ ground state, the $2^{+}$ first excited state at 0.95 MeV, an unresolved pair of $2^{\mathrm{-}}$ and $4^{\mathrm{-}}$ states at 4.4 MeV, and the analogs of the giant electric dipole and spin-dipole resonances around 7.7 MeV have been extracted and compared with previous data at 56 MeV and with microscopic distorted-wave Born approximation calculations. The shapes of angular distributions out to q∼2 ${\mathrm{fm}}^{\mathrm{-}1}$ are well reproduced by the calculations. A comparison of (n,p), (p,n), and (p,p’) cross sections near 60 MeV is made, and a value for ‖${\mathit{J}}_{\mathrm{\sigma }\mathrm{\tau }}$‖ (the volume integral of the central, spin-isospin part of the effective nucleon-nucleon interaction) is extracted. The magnitudes of cross sections for negative-parity states can be qualitatively understood when the loose binding of the sd-shell neutron in the final state and the effect of ground-state correlations on the dipole and spin-dipole strengths are taken into account.