Measurement of the $^{58}$Ni($\alpha$,$\gamma$)$^{62}$Zn reaction and its astrophysical impact

TL;DR

This study measured the $^{58}$Ni($ extalpha$,$ extgamma$)$^{62}$Zn reaction cross sections, compared them to models, and assessed their impact on nucleosynthesis in type Ia supernovae, finding a modest 5% abundance change.

Contribution

The paper provides new experimental cross section data for the $^{58}$Ni($ extalpha$,$ extgamma$)$^{62}$Zn reaction and refines reaction rate predictions for astrophysical models.

Findings

Energy dependence of cross section matches models but absolute values are overestimated.

Rescaling the $ extalpha$ width by 0.45 improves model accuracy.

Nucleosynthesis yields in supernovae are affected by up to 5%.

Abstract

Cross section measurements of the $^{58}$Ni($\alpha$,$\gamma$)$^{62}$Zn reaction were performed in the energy range $E_{\alpha}=5.5-9.5$ MeV at the Nuclear Science Laboratory of the University of Notre Dame, using the NSCL Summing NaI(Tl) detector and the $\gamma$-summing technique. The measurements are compared to predictions in the statistical Hauser-Feshbach model of nuclear reactions using the SMARAGD code. It is found that the energy dependence of the cross section is reproduced well but the absolute value is overestimated by the prediction. This can be remedied by rescaling the $\alpha$ width by a factor of 0.45. Stellar reactivities were calculated with the rescaled $\alpha$ width and their impact on nucleosynthesis in type Ia supernovae has been studied. It is found that the resulting abundances change by up to 5\% when using the new reactivities.