Alpha-alpha interaction reexamined in the context of the Sao Paulo potential: possible applications in astrophysics?
L. Gasques 1*, L. Chamon 1, B. Carlson 2
1 Departmento de Fisica Nuclear, Universidade de Sao Paulo
2 Departmento de Fisica, Instituto Tecnologico de Aeronautica
We have analyzed a large set of alpha-alpha elastic scattering data for bombarding energies ranging from 0.6 to 29.5 MeV. Because of the complete lack of open reaction channels, the optical interaction at these energies must have a vanishing imaginary part. Thus, this system is particularly important because the corresponding elastic scattering cross sections and phase shifts are very sensitive to the real part of the interaction. The data were analyzed in the context of the velocity-dependent Sao Paulo potential, which is a successful theoretical model for the description of heavy-ion reactions from sub-barrier to intermediate energies. We have veriﬁed that, even in this low-energy region, the velocity dependence of the model is a necessary ingredient for describing the data. Possible applications in nuclear astrophysics will be discussed. In particular, predictions of the astrophysical S-factor for the 12C(4He,gama) reaction will be presented.