Analysis of the $^{3}{\rm He}(α, γ)^{7}{\rm Be}$ and $^{3}{\rm H}(α,γ)^{7}{\rm Li}$ astrophysical direct capture reactions in a modified potential-model approach

Abstract

Astrophysical S factors and reaction rates of the direct radiative capture processes 3 He(α, γ) 7 Be and 3 H(α, γ) 7 Li, as well as the primordial abundance of the 7 Li element, are estimated in the framework of a modified two-body potential model. It is shown that suitable modification of phase-equivalent α− 3 He potentials in the d waves can improve the description of the astrophysical S factor for the direct 3 He(α, γ) 7 Be radiative capture reaction at energies above 0.5 MeV. An estimated 7 Li/H abundance ratio of (4.89 ± 0.18) × 10 −10 is in very good agreement with the recent measurement of (5.0 ± 0.3) × 10 −10 by the LUNA collaboration.