Measurement and DWBA analysis of the 12C(6Li, d)16O α-transfer reaction cross sections at 48.2 MeV. R-matrix analysis of 12C(α,γ)16O direct capture reaction data

The angular distributions for low lying states of 16O produced in the 12C(6Li, d)16O α-transfer reaction at have been measured using a high energy resolution position sensitive detection system. The measured cross section data have been analyzed by the FRDWBA theory with a particular emphasis put on the states of astrophysical interest mainly the 1− (7.12 MeV) state. Extracted values of nuclear level parameters (excitation energy, Ex, line width, Γc.m., α-spectroscopic factor, Sα, and reduced α-width, or ) are reported and discussed in comparison to previous ones. The used binding potential corresponds to a long nuclear interaction range (up to a channel radius a=7.7 fm), suggesting that the channel radius a=6.5 fm is likely suitable for the calculations of reduced α-widths near the nuclear surface. However, given that previous DWBA results are available for comparison only near the channel radius a=5.5 fm, calculations have been carried out here for both three preceding a values. Formal values, and of the reduced α-widths (a=6.5 fm) of the 1− (7.12 MeV) and 2+ (6.92 MeV) states have thus been derived. Furthermore, the R-matrix analysis of various data sets of importance to the 12C(α,γ)16O direct capture reaction has been carried out, leading to the range of values for the 1− (7.12 MeV) state, , which is consistent with the preceding DWBA interval, and to a result for the E1 component of the reaction astrophysical factor, , very consistent with most constrained values previously reported in the literature.