Fusion, resonances and scattering in 12C+12C reaction

The variation of fusion cross-section (sigma(fus)) with energy in the C-12+C-12 collision is linked to the underlying resonance phenomenon through the behavior of reaction cross-section (sigma(r)) of which sigma(fus) is taken as a part. The calculation of sigma(fus) is done through an energy-dependent imaginary potential in the optical model potential (OMP). Through dispersion relation, such an imaginary potential gives rise to energy-dependent real potential which is incorporated in the OMP. In our calculation, a form of potential for the nuclear part which has a soft repulsive in-built core is introduced based on similar works done earlier. The calculated results of sigma(fus) are used to explain the oscillatory structure, astrophysical S-factor and the decreasing trend at higher energies of the experimental sigma(fus) data in the case of C-12+C-12 system with remarkable success. The potential used for fusion calculation is tested for fitting elastic scattering data at some energies and is found good in forward angles. Further improvement of the fitting of these data is obtained by incorporating a coupling potential in the surface region. About twenty resonances are observed in our calculation in the specific partial waves and some of them are found close to the experimentally identified resonances in C-12+C-12 reaction. Thus, we provide an integrated and comprehensive analysis of fusion, resonance and scattering data in the best studied case of C-12+C-12 reaction within the framework of optical potential model.