Primordial nucleosynthesis as a probe of fundamental physics parameters

We analyze the effect of variation of fundamental couplings and mass scales on primordial nucleosynthesis in a systematic way. The first step establishes the response of primordial element abundances to the variation of a large number of nuclear physics parameters, including nuclear binding energies. We find a strong influence of the n−p mass difference (for the He abundance), of the nucleon mass (for deuterium) and of A = 3, 4, 7 binding energies (for He, Li and Li). A second step relates the nuclear parameters to the parameters of the Standard Model of particle physics. The deuterium, and, above all, Li abundances depend strongly on the average light quark mass m̂ ≡ (mu +md)/2. We calculate the behaviour of abundances when variations of fundamental parameters obey relations arising from grand unification. We also discuss the possibility of a substantial shift in the lithium abundance while the deuterium and He abundances are only weakly affected.