Detailed study of the astrophysical direct capture reaction 6Li(p,γ)7Be^{6}{\rm Li}(p, \gamma)^{7}{\rm Be} in a potential model approach

The astrophysical $S$ factor and reaction rates of the direct capture process $^{6}$Li(p,$\gamma)^{7}$Be are estimated within a two-body single-channel potential model approach. Central potentials of the Gaussian-form in the $^2P_{3/2}$ and $^2P_{1/2}$ waves are adjusted to reproduce the binding energies and the empirical values of the asymptotic normalization coefficients (ANC) for the $^7$Be(3/2$^-$) ground and $^7$Be(1/2$^-$) excited bound states, respectively. The parameters of the potential in the most important $^2S_{1/2}$ scattering channel were fitted to reproduce the empirical phase shifts from the literature and the low-energy astrophysical $S$ factor of the LUNA collaboration. The obtained results for the astrophysical $S$ factor and the reaction rates are in a very good agreement with available experimental data sets. The numerical estimates reproduce not only the absolute values, but also the energy and temperature dependence of the $S$ factor and reaction rates of the LUNA collaboration, respectively. The estimated $^{7}{\rm Li/H}$ primordial abundance ratio $(4.67\pm 0.04 )\times 10^{-10}$ is well consistent with recent BBN result of $(4.72\pm 0.72) \times 10^{-10}$ after the Planck observation.Comment: 18 pages, 7 figure

Asymptotic normalization coefficient for

This work is aimed at clarifying the contribution of the proton direct radiative capture to the $${}^{12}\mathrm{C}(p,\gamma ){}^{13}\mathrm{N}$$ reaction by specifying the value of the asymptotic normalization coefficient (ANC) for $${}^{12}\mathrm{C}+p\rightarrow {}^{13}\mathrm{N}_\mathrm{g.s.}$$. In order to do this, the differential cross section of the proton transfer in the $${}^{12}\mathrm{C}({}^{10}\mathrm{B},{}^9\mathrm{Be})^{13}\mathrm{N}$$ reaction at an energy of 41.3 MeV has been measured and analyzed through the modified distorted wave Born approximation (MDWBA) method taking into account the reaction channel coupling and $${}^{3}{\mathrm{He}}$$ cluster transfer contributions. The value of the ANC was derived to be 1.63±0.13 fm$$^{-1/2}$$, which was used in estimating the astrophysical S(E) factor and the reaction rate of the proton radiative capture by the $${}^{12}{\mathrm{C}}$$ nucleus at energies of astrophysical relevance

Determination of the

The p - p-chain reaction 3He(α, γ)7Be can sensitively influence the prediction of the 7Be and 8B neutrino fluxes. Despite its importance, the knowledge of its reaction cross section at energies of the core of the Sun (15 keV 30 keV) is limited and the accuracy far from the desired 3% level. In the present paper the indirect measurement of the external capture contribution using the asymptotic normalization coefficient (ANC) technique is reported. The angular distributions of deuterons emitted in the 6Li(3He,d)7Be α-transfer reactions were measured and the ANCs extracted from the scaling of distorted-wave Born approximation (DWBA) and coupled-channel (CC) calculations. Then, the astrophysical S-factor for the 3He(α, γ)7Be reaction was calculated assuming E1 direct capture and the zero energy value turned out to be 0.534 0.025 keVb. Both our experimental and theoretical approaches were benchmarked through the analysis of the 6Li(p,γ)7Be astrophysical factor, with interesting astrophysical applications to the understanding of the primordial lithium problem. In particular, the present work disfavors the occurrence of a claimed 200 keV resonance in the astrophysical factor