Neutron Transfer to the Ground State ofN15in theN14(N14,N13)N15Reaction

The neutron transfer differential cross sections have been measured at center-of-mass energies of 9, 11, 12, 14, and 16 MeV for the ${\mathrm{N}}^{14}$(${\mathrm{N}}^{14}$,${\mathrm{N}}^{13}$)${\mathrm{N}}^{15}$ reaction. The energies of the ${\mathrm{N}}^{13}$ nuclei were measured so that the cross sections determined are known to be associated with the transfer of a neutron to the ground state of the residual ${\mathrm{N}}^{15}$ nucleus. It is found (1) that the total cross section for transfer to the ground state of ${\mathrm{N}}^{15}$ is approximately constant over the range of energies studied in contrast to the results of Toth and (2) that a plot of the differential cross section $\frac{d\sigma }{d{R}_{min}}$ (where $R_{min}$ is the classical distance of closest approach between the nitrogen nuclei) has an exponential dropoff with large $R_{min}$ values that is $\frac{1}{5}$ as steep as that given by the semiclassical tunneling theory of Breit and Ebel at all five energies studied. Finally, by considering recent experimental data taken at reaction energies below the Coulomb barrier where the data do agree with a quantum-mechanical formulation of the tunneling theory, it is argued that the large disagreement between the tunneling theory and the higher energy data presented in this paper can most likely be accounted for by introducing, as Greider has done, a nuclear interaction between the projectile and target nucleus.