New direct measurement of the ~6Li(p,γ)~7Be cross section at LUNA

摘要

The ~6Li(p,γ)~7Be reaction is involved in many astrophysical scenario, ranging from Big Bang Nucleosynthesis to pre-main sequence stellar evolution and solar neutrino. At astrophysical energies, proton capture on ~6Li proceeds through the ~6Li(p,α)~3He and the ~6Li(p,γ)~7Be reactions. A recent measurement of the ~6Li(p,γ)~7Be cross section revealed a possible resonance-like structure at center of mass energy of 195 keV. The observed S-factor could be reproduced introducing a new ~7Be excited state with E ≈ 5800 keV and J~π = (1/2~+, 3/2~+). If confirmed, such excited state might also correspond to a resonance in the ~3He(~4He,γ)~7Be reaction. A new measurement of the ~6Li(p,γ)~7Be cross section at proton energies between 80 and 400 keV has been performed at the Laboratory for Underground Nuclear Astrophysics. A description of the experimental setup and preliminary results of the data analysis is provided.