Spin and parities of 19Ne states of astrophysical interest

Observations of classical nova ejecta show discrepancies with theoretical predictions, particularly for the quantity of material ejected by the explosion. This discrepancy could be resolved with the detection of $\gamma$ rays originating from $^{18}$F. However, theoretical predictions of the flux of these $\gamma$ rays are limited by large uncertainties in the $^{18}$F destruction rates. These uncertainties are caused mainly by the incomplete knowledge of the influence of low energy resonances on the cross section for the main $^{18}$F destruction reaction $^{18}$F(p,$\alpha$)$^{15}$O. In this work we searched for states in the compound nucleus ($^{19}$Ne) relevant at nova temperatures and determined their spin and parities (J$^{\pi}$) when possible. In particular, we found that the state at 6.130 MeV (a proton sub-threshold resonance at E$_{CM}$=-280 keV) has a J$^{\pi}$=3/2$^+$, which opens the possibility for interference in the cross section with the well known broad resonances at E$_{CM}$ = 332 keV and 665 keV. We will present our experimental results and will highlight their effect on the $^{18}$F(p,$\alpha$)$^{15}$O reaction rate.