Analyzing power measurement for theN14(p⃗,γ)O15reaction at astrophysically relevant energies

The ${}^{14}\mathrm{N}\left(\vec{p},\gamma \right){}^{15}\mathrm{O}$ reaction has been investigated by measuring the angular distributions of its cross section and analyzing power using a $270\text{−}\text{keV}$ polarized proton beam. Calculations using a direct-capture-plus-resonance model were compared with the data. The results indicate the presence of $\gamma$ transition amplitudes which were not considered in previous extrapolations of the astrophysical $S$ factor to low energies. The impact on the zero-energy $S$ factor of the ${}^{14}\mathrm{N}\left(\vec{p},\gamma \right){}^{15}\mathrm{O}$ reaction is discussed.