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

Since the discovery of molecular resonances in $$^{12}\hbox {C}+^{12}\hbox {C}$$ 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 $$^{12}\hbox {C}+^{12}\hbox {C}$$ 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.