The effects of coupling variations on BBN

The effect of variations of the fundamental nuclear parameters on big-bang nucleosynthesis are modeled and discussed in detail taking into account the interrelations between the fundamental parameters arising in unified theories. Considering only ⁴He, strong constraints on the variation of the neutron lifetime, neutron-proton mass difference are set. We show that a variation of the deuterium binding energy is able to reconcile the ⁷Li abundance deduced from the WMAP analysis with its spectroscopically determined value while maintaining concordance with D and ⁴He.