$^{19}$F alpha widths from $^{15}$N($\alpha,\alpha$)$^{15}$N data and the $^{18}$F$+p$ reaction rates

The rates of the $^{18}$F($p,\alpha$)$^{15}$O and $^{18}$F ($p,\gamma$)$^{19}$Ne reactions are important for understanding production of the long-lived radioisotope $^{18}$F in novae and the transition to heavy- element production in X-ray bursts. A knowledge of the alpha widths of numerous $^ {19}$Ne levels is critical for calculating these rates. These widths are generally not known and must be extrapolated from information on the isospin mirror nucleus $^{19}$F. Much of this information comes from a measurement of the $^{15}$N($\alpha,\alpha$)$^{15}$N reaction [1], and we have reanalyzed this data using a multilevel $R$-matrix approach to determine properties of resonances in the astrophysically- important range $E_x = 6.4 - 7.5$ MeV. We find the energies and widths of broad levels to be different than previously reported. We have also set upper limits on the widths of postulated 3/2$^{+}$ resonances, analogs of which are important for the $^{18}$F$+p$ reaction rates. The method and results will be presented. \bibitem{smotrich} [1] H. Smotrich {\it et al.}, Phys. Rev. {\bf 122}, 232 (1961).