New Study of the Astrophysical Reaction C-12(alpha,gamma)O-16 via the C-12(Li-7,t)O-16 Transfer Reaction

The C-12(alpha,gamma)O-16 reaction plays an important role in helium burning in massive stars and their evolution. However, despite many experimental studies, the low-energy cross section of C-12(alpha,gamma)O-16 still highly uncertain. The extrapolation of the measured cross sections to stellar energies (E similar to 300 keV) is made difficult by the presence of the two sub-threshold states at 6.92 and 7.12 MeV of O-16. In order to further investigate the contribution of these two-subthreshold resonances to the C-12(alpha,gamma)O-16 cross section, we performed a new determination of the alpha -reduced widths via a measurement of the transfer reaction C-12(Li-7,t)O-16 at two incident energies, 34 and 28 MeV. The measured and calculated differential cross sections will be presented as well as the obtained spectroscopic factors and the alpha -reduced widths.