The rate of the $^{ 25}$Al($p$,$\gamma$)$^{ 26}$Si reaction is one of the few key remaining nuclear uncertainties required for predicting the production of the cosmic $\gamma$-ray emitter $^{ 26}$Al in explosive burning in novae. This reaction rate is dominated by three key resonances ($J^{ \pi}=0^{ +}$, $1^{ +}$ and $3^{ +}$) in $^{ 26}$Si. Only the $3^{ +}$ resonance strength has been directly constrained by experiment. A high resolution measurement of the $^{ 25}$Mg($d$,$p$) reaction was used to determine spectroscopic factors for analog states in the mirror nucleus, $^{ 26}$Mg. A first spectroscopic factor value is reported for the $0^{ +}$ state at 6.256 MeV, and a strict upper limit is set on the value for the $1^{ +}$ state at 5.691 MeV, that is incompatible with an earlier ($^{ 4}$He,$^{ 3}$He) study. These results are used to estimate proton partial widths, and resonance strengths of analog states in $^{ 26}$Si contributing to the $^{ 25}$Al($p$,$\gamma$)$^{ 26}$Si reaction rate in nova burning conditions.
Categories: nucl-ex astro-ph.SR nucl-th