Triple-differential cross sections to discrete states in the(π+16,2p)14N reaction

The ${}_{}{}^{16}{}_{}{}^{}({\pi }^{+}$,2p${)}^{14}$N reaction has been studied at $T_{\pi }$=59.6 MeV. Good energy resolution of 1 to 2 MeV allows several states in ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$ to be resolved. Triple-differential cross sections are presented for the transitions to the ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$ $1^{+}$ ground state and $1^{+}$ 4 MeV state. The quasideuteron model is used to construct a T matrix for each transition. A fit to the data requires an additional term in the T matrix giving a large anisotropy in the angular distribution of the ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$ recoil momentum vector. The ground state T matrix has an unexpected enhancement near zero recoil momentum of the ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$ nucleus. The ‘‘measured’’ T matrices are then used to extrapolate to unmeasured regions of phase space giving double differential, single-differential, and total cross sections for each transition.