Constraint of the Astrophysical $^{26g}$Al(p;γ)$^{27}$Si Destruction Rate at Stellar Temperatures

The Galactic 1.809-MeV γ-ray signature from the β decay of $^{26g}$Al is a dominant target of γ-ray astronomy, of which a significant component is understood to originate from massive stars. The $^{26g}$Al(p; γ)$^{27}$Si reaction is a major destruction pathway for $^{26g}$Al at stellar temperatures, but the reaction rate is poorly constrained due to uncertainties in the strengths of low-lying resonances in $^{27}$Si. The $^{26g}$Al(d; p)$^{27}$Al reaction has been employed in inverse kinematics to determine the spectroscopic factors, and hence resonance strengths, of proton resonances in $^{27}$Si via mirror symmetry. The strength of the 127-keV resonance is found to be a factor of 4 higher than the previously adopted upper limit, and the upper limit for the 68-keV resonance has been reduced by an order of magnitude, considerably constraining the $^{26g}$Al destruction rate at stellar temperatures.