Anisotropy and cosmic nucleosynthesis of light isotopes including ⁷Li

An improved numerical model on primordial nucleosynthesis in an anisotropic cosmology is used to calculate the produced mass fractions of ²H, ³He, ⁴He, ⁷Li. The results are presented as a function of two parameters: B₀, the anisotropy/radiation energy density ratio at T=5×10¹⁰ K, and η, the present baryon/photon ratio. The anisotropic results show that for fixed η there is practically no decrease with anisotropy in any of the abundances considered, and most increase. The relative increases found are for ²H: B₀×1%; ³He: 0; ⁴He: B₀×3%; ⁷Li: B₀×6% for η<2×10^-10 and 0 for η>5×10^-10. This linear approximation is good for moderate values of B₀. Larger anisotropy (B₀>owig5) is unrealistic because of excess ⁴He production.