Nuclear aspects of Primordial Nucleosynthesis related to Lithium production
Abstract
Primordial nucleosynthesis is one of the three evidences for the Big-Bang model together with the expansion of the Universe and the Cosmic Microwave Background. There is a good global agreement over a range of nine orders of magnitude between abundances of 4He, D, 3He and 7Li deduced from observations and calculated primordial nucleosynthesis. This comparison was used to determine the baryonic density of the Universe. For this purpose, it is now superseded by the analysis of the Cosmic Microwave Background (CMB) radiation anisotropies. Big-Bang nucleosynthesis remains, nevertheless, a robust probe of the physics of the early Universe. However, the yet unexplained, discrepancy between the calculated and observed lithium primordial abundances, has not been reduced by recent nuclear physics experiments. We extended the nuclear network to more than 400 reactions, until sodium, to evaluate the primordial 6Li, B, Be and CNO abundances and search for extra source of neutrons could solve the lithium problem by destroying 7Be. We performed a sensitivity study of this extended network to identify new important reactions but noted the stability of Big Bang nucleosynthesis results from 4He, D, 3He and 7Li to CNO. Other sources of extra neutrons could be found in more exotic scenarios, for instance the decays or annihilation of dark matter particles.
- Publication:
-
Memorie della Societa Astronomica Italiana Supplementi
- Pub Date:
- 2012
- Bibcode:
- 2012MSAIS..22..172C
- Keywords:
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- Cosmology: early Universe;
- Nuclear reactions;
- nucleosynthesis;
- abundances