An analysis of the 12C+12C reaction using a new type of coupling potential

Full text: 12C+12C system has been one of the most extensively studied reaction so far and is a subject attracting continuous interest from both theoretical and experimental point of views. Therefore, a large body of data over a wide energy range has been accumulated for this system from the systematic studies. The previous works in the literature clearly show that the standard coupled-channel approach is inadequate to explain the problems of this rection. It can fit neither any of the individual angular distributions nor the 90 deg. elastic scattering excitation function. In our couple-channels (CC) calculations, the interaction between the 12C nuclei is described by a deformed optical potential. The real potential has the square of a Woods-Saxon shape. The imaginary potential has the standard Woods-Saxon volume shape and its depth increases quadratically with energy as: W=-2.69+0.145ELab+0.0009(ELab)2. The 12C nucleus has a static quadrupole deformation and its excitation is described within the rotational model. The empirical deformation parameter, β2=-0.6, is used in these calculations. The limitations of the standard coupled-channels method, on the one hand, and the oblate character of thr 12C and the prolate character of the compound nucleus 24Mg, on the other hand, compelled us to use a new type of coupling potential which is ablate (attractive) when two 12C nuclei are at large distances and prolate (repulsive) when they are at short distances. For the new CC case, the agreement is very good for the elastic scattering, single-2+ and mutual-2+ excitation inelastic scattering data over the whole energy range studied. The theoretical predictions of the magnitudes and the phase of the oscillations for the mutual-2+ excitation inelastic scattering data, which have been the major outstanding problems of the reaction, are in a very good agreement with the empirical values