Towards a microscopic description of 12C+12C fusion at stellar energies

TL;DR

This paper develops a microscopic model for 12C+12C fusion at stellar energies, accurately describing scattering, fusion, and nuclear states, and supporting the fusion hindrance hypothesis with detailed resonance analysis.

Contribution

It introduces a fully microscopic multichannel RGM approach that simultaneously describes fusion, scattering, and nuclear spectroscopy for 12C+12C, improving upon previous models.

Findings

Excellent agreement with experimental elastic scattering data.

Revealed highly mixed 24Mg states, challenging pure molecular state concept.

Predicted resonance structures and fusion hindrance at low energies.

Abstract

I present a fully microscopic description of the 12C+12C fusion reaction at stellar energies. Utilizing the multichannel Resonating Group Method (RGM), my model explicitly includes 12C+12C and alpha+20Ne reaction channels (with excited states). This approach provides a consistent, simultaneous, description of fusion, elastic scattering, and 24Mg spectroscopy. Results for 12C+12C elastic scattering show excellent agreement with experimental data, significantly improving the single-channel approximations. Spectroscopic analysis reveals that 24Mg states and resonances are highly mixed configurations, contradicting the concept of pure "molecular states." The calculated fusion S-factor is consistent with available experimental data and predicts both narrow and broad resonances near the Coulomb barrier. Main resonance widths originate primarily from the alpha+20Ne exit channels. The S-factor exhibits a decrease at low energies, providing a microscopic support for the hypothesis of fusion hindrance. This work is a first step towards a reliable theoretical extrapolation of the 12C+12C reaction to deep stellar burning temperatures. Future works should include the neutron and proton channels to provide a complete description of the 12C+12C fusion.