Status on $\mathbf{{}^{12}{\rm C}+{}^{12}{\rm C}}$ fusion at deep subbarrier energies: impact of resonances on astrophysical $S^{*}$ factors

TL;DR

This paper reviews the status of $^{12}$C+$^{12}$C fusion research at deep subbarrier energies, focusing on how resonances influence astrophysical $S^{*}$ factors, with comparisons between direct and indirect measurement methods.

Contribution

It provides a comprehensive overview of experimental findings and discusses the impact of resonances on fusion rates relevant to astrophysics, highlighting analysis issues in the Trojan horse method.

Findings

Resonances significantly affect $^{12}$C+$^{12}$C fusion at low energies.

Modified $S^{*}$ factors have been extracted from both direct and indirect measurements.

Discrepancies and analysis challenges in the Trojan horse method are discussed.

Abstract

Since the discovery of molecular resonances in $^{12}$C+$^{12}$C in the early sixties a great deal of research work has been undertaken to study $\alpha$-clustering and resonant effects of the fusion process at sub-Coulomb barrier energies. The modified astrophysical $S^{*}$ factors of $^{12}$C+$^{12}$C fusion have been extracted from direct fusion measurements at deep sub-barrier energies near the Gamow window. They were also obtained by the indirect Trojan horse method (THM). A comparison of direct measurements and the THM, which elucidates problems in the analysis of the THM, is discussed in this Letter to the Editor.