New reaction rates for improved primordial D/H calculation and the cosmic evolution of deuterium

Understand

Primordial or big bang nucleosynthesis (BBN) is one of the three historical strong evidences for the big bang model.

• Standard BBN is now a parameter free theory, since the baryonic density of the Universe has been deduced with an unprecedented precision from observations of the anisotropies of the cosmic microwave background (CMB) radiation.
• There is a good agreement between the primordial abundances of 4He, D, 3He and 7Li deduced from observations and from primordial nucleosynthesis calculations.
• However, the 7Li calculated abundance is significantly higher than the one deduced from spectroscopic observations and remains an open problem.