C-12(N,P)B-12 Reaction At 56, 60, And 65 Mev

The C-12(n,p)B-12 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- and 4- 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 approximately 2 fm-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 \J-sigma-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.