Key points are not available for this paper at this time.
Calculations of primordial nucleosynthesis are performed and used to study the dependence of the predicted abundances on the number of neutrino flavors and the time variation of the gravitational constant. Constraints on the primordial abundance of He-4 are reviewed, and it is suggested that this abundance, Y, is not greater than about 0.25. Severe constraints are placed on the number of lepton flavors (i.e., the number of types of light two-component neutrino), the present nucleon density, and the time variation of the gravitational constant. Primordial abundances of D, He-3, He-4, and Li-7 are computed for several values of lepton number over a range of nucleon densities. The results are compared with the observed abundances of D and Li-7. It is concluded that the universe cannot be closed by nucleons.
Yang et al. (Mon,) studied this question.