Elastic scattering of protons from 15 N

Background: Resonances observed through elastic scattering of protons on ${}^{15}$N can provide information about the partial widths, spin parities, and energies of excited states in ${}^{16}$O near the proton separation energy. This is the same energy region important for the nuclear astrophysics reactions ${}^{15}$N${(p,\ensuremath{\gamma})}^{16}$O and ${}^{15}$N${(p,\ensuremath{\alpha})}^{12}$C. While previous measurements have been made, they are limited in scope, especially in their angular coverage. Purpose: Obtain additional ${}^{15}$N${(p,p)}^{15}$N reaction data which can be used in a global multiple-channel $R$-matrix analysis of the ${}^{16}$O compound nucleus in order to better constrain the level parameters of states which contribute to the reaction ${}^{15}$N${(p,\ensuremath{\gamma})}^{16}$O. Methods: Measure the excitation functions of ${}^{15}$N${(p,p)}^{15}$N over an energy range from ${E}_{p}$ $=$ 0.6 to 1.8 MeV at laboratory angles of 90${}^{\ensuremath{\circ}}$, 105${}^{\ensuremath{\circ}}$, 135${}^{\ensuremath{\circ}}$, 150${}^{\ensuremath{\circ}}$, and 165${}^{\ensuremath{\circ}}$. The reaction ${}^{15}$N${(p,{\ensuremath{\alpha}}_{0})}^{12}$C was measured concurrently. Results: Ratios of the excitation functions were extracted from the yield data. Resonances were identified in the yield ratio data which correspond to previously reported levels in ${}^{16}$O. An $R$-matrix analysis, which fits the present data as well as previous measurements from the literature simultaneously, finds reasonable agreement between the current measurements and those in the literature. Conclusions: The additional data from this measurement will be combined with previous literature data in a comprehensive $R$-matrix analysis of reactions which populate ${}^{16}$O over a similar energy region.