Importance of the sequential two-step transfer process in A ΔS = 1 and ΔT = 1 inelastic transition of the 14N(p, p') 14N reaction

Abstract

Differential cross sections and vector analyzing powers for 14N(p, p′) and 14N(p′, d) reactions have been measured at E p = 21.0 MeV to elucidate the reaction mechanism and the effective interaction for the ΔS = ΔT = 1 transition in the 14N(p, p′) 14N(2.31 MeV) reaction. The data are analyzed in terms of the finite-range distorted-wave Born approximation (DWBA) which includes direct, knock-on exchange and (p, d) (d, p′) two-step processes. Shell-model wave functions of Cohen and Kurath are used. The data for the first excited state are reasonably well explained by including a two-step process in the calculations. The two-step process explains half of the experimental intensity. Moreover the vector analyzing power cannot be explained without introducing this two-step process. The vector analyzing power of protons leading to the second excited state in 14N is better explained by introducing a macroscopic calculation. The data for the 14N(p, d) 13N (g.s.) reaction are well described by a DWBA calculation using a modified deuteron optical potential. The knock-on exchange contribution is relatively small. The importance of this two-step process for ΔS = ΔT = 1 transitions up to 40 MeV is discussed.