What is the big-bang-nucleosynthesis prediction for the baryon density andhow reliable is it? art. no. 063512

Together, the standard theory of big-bang nucleosynthesis (BBN) and the pri meval deuterium abundance now very precisely peg the baryon density. Based upon our analysis of the deuterium data and the theoretical uncertainties a ssociated with the BBN predictions, we determine Omega (B)h(2) = 0.020 +/- 0.002 (95% C.L.), with the uncertainty from the measured deuterium abundanc e about twice that from the predicted abundance. We discuss critically the reliability of the BBN baryon density, and in light of possible systematic uncertainties also derive a very conservative range. We conclude that withi n the standard cosmology and standard theory of BBN a baryon density Omega (B)h(2)=0.032 (the central value implied by recent CMB anisotropy measureme nts) simply cannot be accommodated.