Reanalysis of the astrophysical S(E) factors of the 6Li(d,α)4He, 7Li(p,α)4He and 6Li(p,α)3He reactions

The experimental data of the Li-6(d,alpha)He-4, Li-7(p,alpha)He-4 and Li-6(p,alpha)He-3 reactions obtained by other groups are reanalyzed in this work to extract their respective astrophysical S(E) factors and the screening energies provided by different environments (LiF solid targets and molecular H-2 or D-2 gas targets). Different from previous authors who investigated these three reactions independently, we study them simultaneously, based on the hypothesis that the screening effects are independent of the isotopic effects and the fact that the screening effects depend on the environments. The present extracted astrophysical S(E) factors result in S-bare(0) = 20.5 +/- 0.5, 0.0616 +/- 0.0017 and 3.63 +/- 0.13 MeV b for the Li-6(d,alpha)He-4, Li-7(p,alpha)He-4 and Li-6(p,alpha)He-3 reactions, respectively. The screening energies are 310 +/- 109 and 218 +/- 38 eV for the LiF solid targets and molecular H-2 or D-2 gas targets, respectively. These deduced screening energies are smaller than that observed by Engstler et al, and the value of U-s = 218 +/- 38 eV for the molecular H-2 or D-2 gas targets coincides with the value of 186 eV estimated from the adiabatic limit, while the value of U-s = 310 +/- 109 eV for the LiF solid targets is still slightly larger than that estimated from theoretical predictions.