The lithium problem: new insight in the big bang nucleosynthesis (BBN) beyond the standard model

The production of the light elements in the framework of the standard Big Bang nucleosynthesis model (SBBN) matches the observed abundances except in case of 7Li, where observations lie a factor 2.4-4.3 below SBBN+WMAP(Wilkinson Microwave Anisotropy Probe) predictions. This so-called "Lithium problem" needs to be resolved beyond the SBBN. In this contribution we focus on the effect of degenerate neutrinos and the addition of dark component, including dark energy density and dark entropy. We find that the effect of the degeneracy parameter is significant if chemical potentials of neutrino families are different. Concerning the dark component, the major effect comes from adding dark entropy.