Speaker
Description
Observation of the 1.809-MeV $\gamma$ ray from $^{26}$Al decay ($T_{1/2} = 7.17\times10^5$ yr) in our galaxy evinces that nucleosynthesis is currently ongoing. $^{26}$Al is produced in a variety of stellar sites, including classical novae. For the temperatures reached in classical novae, an alternative $^{26}$Al production pathway exists via the $^{25}$Al($p,\gamma$)$^{26}$Si($\beta^+$)$^{26}$Al$^\text{m}$ reaction, wherein the $^{26}$Al$^\text{m}$ decays directly to the $^{26}$Mg ground state and does not emit the characteristic $\gamma$ ray. Thus, the total amount of 1.809-MeV $\gamma$-ray emission depends strongly on the $^{25}$Al($p$,$\gamma$)$^{26}$Si reaction rate, which has been identified as the main source of uncertainty in determining the $^{26}$Al production in classical novae. To improve our knowledge of the $^{26}$Si resonances above the proton threshold that contribute to this rate, we study the analog states of the mirror nucleus $^{26}$Mg using a neutron transfer reaction, $^{25}$Mg($d,p$)$^{26}$Mg. This reaction was measured at the Split-Pole magnetic spectrometer at the ALTO facility of IJCLab, with a 12-MeV deuteron beam impinging on an enriched $^{25}$MgO target. I will present our results in the context of the nearly two orders of magnitude tension in the literature [Yas90, Ham20] for the neutron spectroscopic factor of the 5.691-MeV ($1^+$) state. The analog 5.676-MeV ($1^+$) resonance in $^{26}$Si is one of three resonances expected to dominate the reaction rate at nova burning temperatures.
[Yas90] M. Yasue et al. Phys Rev C 42, 4 (1990)