Spin and parities of sub-threshold resonances and their interference effects in the $^{18}$F destruction reaction $^{18}$F(p,$\alpha$)$^{15}$O

The $^{18}$F(p,$\alpha$)$^{15}$O reaction dominates $^{18}$F destruction in classical nova explosions. However, uncertainties in its cross section at low energy place a poor constraint on the $^{18}$F abundances predicted by nova models. The incomplete knowledge of the interference effects between broad resonances (e.g. at E$_{CM}$ = 665 keV) and those near the proton-threshold constitutes an important source for these uncertainties. Accurately determining resonance parameters such as energies, spin and parities (J$^{\pi}$), and widths of sub-threshold and unbound states is crucial to study these interference effects. In this talk we will present the results of a $^{20}$Ne($^{3}$He,$\alpha$)$^{19}$Ne neutron pickup reaction performed at the Triangle Universities Nuclear Laboratory using its Enge split-pole magnetic spectrograph. In particular, we will show results of the analysis done to determine the J$^{\pi}$ of the 6.290 MeV state (E$_{CM}$ -120 keV resonance). Also, we will present the results for the 6.132 MeV state (E$_{CM}$= -278 keV) together with other states of astrophysical interest, and highlight their effect on the $^{18}$F(p,$\alpha$)$^{15}$O reaction rate at nova temperatures.