We have measured the differential cross sections of the ($p$,$n$) reaction of ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$, ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, and ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$ to the ground state of the final nucleus ($\Delta J=1\mathrm{}$, $\Delta T=1\mathrm{}$, $\Delta \pi =0\mathrm{}$) and to the 7.77 MeV excited state of ${}_{}{}^{14}{}_{}{}^{}\mathrm{O}$ at $E_p=144\mathrm{}$ MeV and $\mathrm{O}°<{\theta }_{\mathrm{lab}}<20\mathrm{}°$. For the ground state cases, we treat the nuclei as elementary particles, which are assigned the initial nucleus-pion-final nucleus coupling constants predicted using the partially conserved axial vector current. The Born helicity amplitudes for one-pion exchange are presented along with a method for including distortions in momentum space. The calculations which have no free parameters agree with the data for ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$ and ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, but not for ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$.

NUCLEAR REACTIONS ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$($p$,$n$), ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$($p$,$n$), and ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$($p$,$n$) at $E_p=144\mathrm{}$ MeV. Differential cross sections measured between 0° and 20° (lab). Initial nucleus-pion-final nucleus coupling constants extracted.

• Received 29 October 1979

DOI:https://doi.org/10.1103/PhysRevC.21.2211