ABSTRACT
One of the main successes of the standard early-universe cosmology is the prediction of the abundances of the light elements, D, 3He, 4He and 7Li. Agreement between theory and observation is obtained for a certain range of the parameter ηB, the ratio of baryon density and photon density [1],
= (4.7−6.5)×10−10 , (1)
where the present number density of photons is nγ ∼ 400/cm3. Since no significant amount of antimatter is observed in the universe, the ratio ηB coincides with the cosmological baryon asymmetry, ηB = (nB−nB¯)/nγ .
