Coupled variations of fundamental couplings and primordial nucleosynthesis

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 He-4, strong constraints on the variation of the neutron lifetime, neutron-proton mass difference are set. These constraints are then translated into constraints on the time variation of the Yukawa couplings and the fine structure constant. Furthermore, we show that a variation of the deuterium binding energy is able to reconcile the Li-7 abundance deduced from the WMAP analysis with its spectroscopically determined value while maintaining concordance with D and He-4. The analysis is strongly based on the potential model of Flambaum and Shuryak that relates the binding energy of the deuteron with the nucleon and sigma and omega mesons masses; however, we show that an alternative approach that consists of a pion mass dependence necessarily leads to equivalent conclusions.