Absolute cross sections measurement for the 12C + 12C system at astrophysically relevant energies Original Research Article

The 12C + 12C fusion reaction has been studied in the center-of-mass energy range of 2.25 to 6.01 MeV. Through the detection of gamma rays from the first excited states of the residual nuclei 20Ne, 23Na and 23Mg, absolute cross sections for the 12C(12C, α), 12C(12C, p) and 12C(12C, n) reactions have been obtained. In this new measurement, the energy dependence of the S-factor is found to increase as the energy decreases below 3 MeV in the center of mass. This tendency was observed in previous measurements by Mazarakis et al., and has since then become a subject of controversy. In this work, where the cross sections are measured at even lower energies, we confirm the rise in the S-factor toward the energy region relevant for star evolution and nucleosynthesis calculations (Ec.m.=1–3 MeV).