Impact of the $^6$Li asymptotic normalization constant onto $\alpha$-induced reactions of astrophysical interest

TL;DR

This paper investigates how the $^6$Li asymptotic normalization constant influences $ ext{α}$-induced reactions relevant to astrophysics, demonstrating that first-principle calculations can significantly refine reaction rate estimates and resolve experimental discrepancies.

Contribution

It introduces a first-principles calculation of $^6$Li that reduces uncertainties in $ ext{α}$-induced reaction cross sections and improves the theoretical understanding of these processes.

Findings

$^{12}$C$( ext{α}, ext{γ})^{16}$O cross section reduced by 21%

Resolves discrepancies in $^{13}$C$( ext{α},n)^{16}$O measurements

Highlights need for improved nuclear reaction models

Abstract

Indirect methods have become the predominant approach in experimental nuclear astrophysics for studying several low-energy nuclear reactions occurring in stars, as direct measurements of many of these relevant reactions are rendered infeasible due to their low reaction probability. Such indirect methods, however, require theoretical input that in turn can have significant poorly-quantified uncertainties, which can then be propagated to the reaction rates and have a large effect on our quantitative understanding of stellar evolution and nucleosynthesis processes. We present two such examples involving $\alpha$-induced reactions, $^{13}$C($\alpha,n)^{16}$O and $^{12}$C$(\alpha,\gamma)^{16}$O, for which the low-energy cross sections have been constrained with $(^6$Li$,d)$ transfer data. In this Letter, we discuss how a first-principle calculation of $^6$Li leads to a 21% reduction of the $^{12}$C$(\alpha,\gamma)^{16}$O cross sections with respect to a previous estimation. This calculation further resolves the discrepancy between recent measurements of the $^{13}$C$(\alpha,n)^{16}$O reaction and points to the need for improved theoretical formulations of nuclear reactions.