EDP Sciences
Planck 2015 results
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Fig. 35


Predictions of standard BBN for the primordial abundance of 4He (top) and deuterium (bottom), as a function of the baryon density ωb. The width of the green stripes corresponds to 68% uncertainties on nuclear reaction rates and on the neutron lifetime. The horizontal bands show observational bounds on primordial element abundances compiled by various authors, and the red vertical band shows the Planck TT+lowP+BAO bounds on ωb (all with 68% errors). The BBN predictions and CMB results shown here assume Neff = 3.046 and no significant lepton asymmetry.