Radiative 3He(2H,γ)5Li Capture at Astrophysical Energy and Its Possible Role in Accumulation of 6Li at the BBN

Abstract

The Big Bang Nucleosynthesis (BBN) relevance reactions 3He(2H, γ)5Li, 3H(3He, γ)6Li, and 5Li(n, γ)6Li are treated as a source of 6Li formation. Comparison of the numerical reaction rates of these processes, the prevalence of light elements suggest that the two-step process 2H + 3He → 5Li + γ and n + 5Li → 6Li + γ can make a significant contribution, of the order of unity, to the formation of 6Li nuclei at the BBN at least at temperatures T9. Calculations of the total cross sections, astrophysical S-factor, and reaction rates have been performed for 3He(2H, γ)5Li radiative capture reaction within the framework of the modified potential cluster model with forbidden states, which follow from the classification of the orbital cluster states according to Young diagrams. Numerical data and corresponding parametrizations cover the energy range 100 keV < E c.m. < 5 MeV and temperature ranges 0.01 < T9 < 10. Detailed up-to-date experimental data for the reaction 3He(2H, γ)5Li are analyzed.