EXPERIMENTAL, COMPUTATIONAL, AND OBSERVATIONAL ANALYSIS OF PRIMORDIAL NUCLEOSYNTHESIS

We present a comprehensive evaluation of the current status of the standard theory of primordial nucleosynthesis. We determine the 12 nuclear reactions most important for the production of the light elements and conduct a detailed study of their rates and uncertainties, incorporating these into a Monte Carlo analysis to properly evaluate uncertainties in the computed elemental abundances. We then compare these predicted abundances with primordial abundances deduced from astronomical observations of the light elements D, He-3. He-3, and Li-7 and find a consistent agreement over a narrow range of the baryon-to-photon ratio eta, thereby supporting the standard theory of big bang nucleosynthesis. This 77 range corresponds to a constraint on the baryon density parameter of 0.01 less-than-or-equal-to OMEGA(b) less-than-or-equal-to 0.09, where the primordial D + He-3 abundance sets the lower bound and the He-4 abundance sets the upper bound. The new reaction rates cause an increase in the upper bound from Li-7 by 40% over that determined in previous studies. With this new constraint on OMEGA(b), observational evidence for Y(p) < 0.237 will require either a reinterpretation of the D + He-3 bound or modifications to standard nucleosynthesis theory.