Sharpening the predictions of big-bang nucleosynthesis

We have reexamined the nuclear inputs to big-bang nucleosynthesis using Mon te Carlo realization of the cross-section data to directly estimate theoret ical uncertainties for the yields of D, He-3, and Li-7. Our results indicat e that previous estimates of the uncertainties were too large by a factor o f 2. Using the Burles-Tytler deuterium measurement, we infer a baryon densi ty Omega(B)/h(2) = 0.019 +/- 0.0024, predict a primeval He-4 mass fraction Yr = 0.246 +/- 0.0014, and obtain a limit to the equivalent number of neutr ino species N-v < 3.20 (all at 95% C.L.). We also identify key reactions an d the energies, where improved data would allow further progress. [S0031-90 07(99)09188-7].