The nuclear physics uncertainty associated with the production of the Galactic $\beta$-delayed $\gamma$-ray emitter ${}^{26}\mathrm{Al}$ in classical novae is currently dominated by the uncertainty in the thermonuclear ${}^{25}\mathrm{Al}(p,\gamma ){}^{26}\mathrm{Si}$ reaction rate. By combining the results of recent experiments with past work, the center-of-mass energy of the key $J^{\pi }=3^{+}$, ${}^{25}\mathrm{Al}(p,\gamma ){}^{26}\mathrm{Si}$ resonance is determined to be $412(2)$ keV, and a lower limit of ${\Gamma }_p/{\Gamma }_{\gamma }>5.6$ is set for this resonance. The resulting large reduction in the ${}^{25}\mathrm{Al}(p,\gamma ){}^{26}\mathrm{Si}$ rate uncertainty is expected to constrain uncertainties in the nova contribution to Galactic ${}^{26}\mathrm{Al}$.

• Received 12 November 2008

DOI:https://doi.org/10.1103/PhysRevC.79.035803