Big Bang nucleosynthesis and the results of the ²H(α,γ)⁶Li experiment at LUNA

Observations of the ⁶Li abundance in very metal-poor stars, if confirmed, show a level of ⁶Li that is several orders of magnitude larger than the production of this nuclide in standard Big Bang nucleosynthesis. The ²H(α,γ)⁶Li nuclear reaction is believed to dominate ⁶Li production in the Big Bang, but there are no directly measured data at relevant energies yet. The reaction has been studied at the LUNA 0.4 MV accelerator, deep underground in the Gran Sasso laboratory in Italy, using an intensive He+ beam and a windowless deuterium gas target. The conclusions from the final data analysis of the experiment will be presented. – Supported in part by DFG (BE 4100/2-1).