New reaction rates for the destruction of Be-7 during big bang nucleosynthesis measured at CERN/n_TOF and their implications on the cosmological lithium problem

Abstract

New measurements of the Be-7(n,alpha)He-4 and Be-7(n,p)Li-7 reaction cross sections from thermal to keV neutron energies have been recently performed at CERN/n_TOF. Based on the new experimental results, astrophysical reaction rates have been derived for both reactions, including a proper evaluation of their uncertainties in the thermal energy range of interest for big bang nucleosynthesis studies. The new estimate of the Be-7 destruction rate, based on these new results, yields a decrease of the predicted cosmological Li-7 abundance insufficient to provide a viable solution to the cosmological lithium problem.