The (3He,t) reaction at intermediate energies: Spin-isospin transitions to states in 12N and 13N

The (3He, t) reaction has been studied at intermediate energies, 600 MeV–2.3 GeV. The reaction is a single-step direct reaction, and the angular distributions are well described by DWIA calculations. At these energies the σρ component of the interaction dominates. The ratio of the isovector strengths ¦J σρ / ρ ¦ derived from the data on 13C appears to remain roughly constant in the energy range 300–700 MeV per nucleon. The triton spectra exhibit a prominent quasi-free peak. The data at momentum transfers q ⪢ 1.7 fm−1 show a shift of the peak towards smaller energy loss than observed in (e, e') experiments at corresponding four-momentum transfers. The shift becomes progressively larger with increasing q and is about 45 MeV at q = 2.5 fm−1. The shift may be caused by particle-hole correlations in the spin-longitudinal channel.