C-12+C-12 fusion in a multichannel folding model

Abstract

The C-12+C-12 fusion reaction is investigated using a folding potential in a multichannel approach involving the C-12(0(1)(+),2(+), 0(2)(+), 3(-)) states. The C-12 densities (including transition densities) are taken from the RGM calculation of Kamimura. For the nucleon-nucleon interaction, we use the DDM3Y density-dependent interaction. Owing to the explicit presence of inelastic channels, the imaginary part of the optical potential only contains a short-range fusion contribution. The S-factor is then virtually insensitive to the precise value, and the model is free of any fitting parameter. From the coupled-channel system, we determine the elastic and fusion cross sections simultaneously. As elastic data are available around the Coulomb barrier, this simultaneous treatment offers a good test for the reliability of the model. In the fusion cross section, the role of the inelastic channels and, in particular of the C-12(0(1)(+))+C-12(0(2)(+)) channel involving the Hoyle state, is discussed.