Speaker
Description
The ¹²C+¹²C fusion reaction plays essential roles in various astrophysical phenomena, including carbon burning in massive stars, Type Ia supernova ignition, and X-ray superbursts. However, its reaction rate at low temperatures remains highly uncertain due to difficulties in direct measurements. In this talk, we discuss our recent microscopic studies of the ¹²C+¹²C fusion reaction based on antisymmetrized molecular dynamics (AMD) and generator coordinate method (GCM) calculations employing several nuclear energy‑density functionals. This fully microscopic model describes multi-nucleon rearrangement, channel coupling, and nuclear deformation without adjustable parameters.
Our AMD approach successfully reproduces cross sections above the Gamow window of X-ray superbursts. It predicts several 0⁺ and 2⁺ molecular resonances within the Gamow window, resulting in pronounced S‑factor peaks without showing low‑energy hindrance. We systematically investigate the dependence of resonance properties and reaction rates on different density functionals. Gogny functionals predict strong low-energy resonances that enhance the reaction rate, whereas Skyrme functionals yield weaker low‑energy structures, leading to reaction rates closer to the hindrance model.
We will also discuss future directions to reduce these uncertainties. A key step is the experimental identification of deep sub‑barrier 0⁺ and 2⁺ molecular resonances. Our calculations predict enhanced isoscalar monopole and quadrupole strengths, indicating that α‑inelastic scattering on ²⁴Mg is a promising probe that can bypass the Coulomb barrier. It is expected to significantly reduce the uncertainty in the ¹²C+¹²C reaction rate and improve simulations of stellar explosions.