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tokens: f.u., is obtained from the 16th and 84th percentiles. The lognormal parameters, μ and σ , can be calculated from the recommended (median) rate ( x med = e μ ) and the factor uncertainty ( f.u . = e σ ; for a coverage probability of 68%). The rate factor uncertainty is 1.1% for both reactions at most temperatures. Figure 6. Reaction rate probability density of d(d, n) 3 He at different temperatures. The rate samples (red histograms) are computed using the S -factor samples obtained from the Bayesian analysis. Blue curves represent lognormal approximations, where the lognormal parameters μ (“mu”) and σ (“sig”) are directly calculated from the expectation value and variance of all rate samples, ln(), at a given temperature. T9 is the temperature in GK. Figure 7. Reaction rate probability density of d(d, p) 3 H at different temperatures. The rate samples (red histograms) are computed using the S -factor samples obtained from the Bayesian analysis. Blue curves represent lognormal approximations, where the lognormal parameters μ (“mu”) and σ (“sig”) are directly calculated from the expectation value and variance of all rate samples, ln(), at a given temperature. T9 is the temperature in GK. Table 3 Present Recommended Reaction Rates a Note. a Reaction rates in units of cm 3 mol −1 s −1 , corresponding to the 50th percentile of the rate probability density function. The rate factor uncertainty, f.u., is obtained from the 16th and 84th percentiles (see the text). The parameters μ and σ of the lognormal approximation to the reaction rate are given by x med = e μ and f.u . = e σ , respectively, where x med denotes the median rate. Values for T > 2 GK, shown in italics, are adopted from Coc et al. ( 2015 ). The present rates for d(d, n) 3 He and d(d, p) 3 H agree with the results of Coc et al. ( 2015 ) within 1% at most temperatures. However, our rates are more than 15% larger than those of Coc et al. ( 2015 ) at very low temperatures (near 1 MK). This is caused by a low-energy cutoff that is too high for the numerical integration of the rates in the previous analysis. The theoretical model of Arai et al. ( 2011 ) only applies to low energies, thus we can derive Bayesian reaction rates only up to a temperature of 2 GK. The results in Table 3 for higher temperatures, shown in italics, are adopted from Coc et al. ( 2015 ). The most important temperatures for BBN are near 1 GK, corresponding to an effective kinetic energy range of 250 keV for the d+d reactions. The last step is to calculate the effect of the new reaction rates on the predicted primordial D/H ratio. The Bayesian mean value for the scale factor is larger by 0.21% for d(d, n) 3 He and larger by 0.12% for d(d, p) 3 H compared to Coc et al. ( 2015 ). The discrepancies of both reaction rates (0.21% and 0.12%, respectively), weighted by the sensitivity of the D/H abundance ratio to each reaction rate variation (−0.54 and −0.46, respectively; Coc Vangioni 2010 ), result in a 0.113% and