A uniform primordial deuterium abundance stemmed from QSO observations

Abstract

The discordance between `low&#39; and `high&#39; primordial D/H measurements can be considerably reduced if the analysis of the H+D profiles accounts for the correlated velocity field of bulk motion. We have re-estimated the value of D/H at z=3.572 towards Q1937--1009 (`low&#39; D/H=(3.3+/-0.3)10^{-5} [3]) and at z=0.701 towards Q1718+4807 (`high&#39; D/H=(2.0+/-0.5)10^{-4} [15]) and found that a single D/H value from the range (3.5-5.2)10^{-5} (2σC.L.) is sufficient to describe both spectra. This result supports homogeneous models of BBN. The obtained D/H ratio and the measurements of high He4 abundance in extra-galactic HII regions [5] and Li7 abundance in metal-poor halo stars [2] are consistent, within the errors, with the predictions of standard BBN for 3.6 <= η_{10} <= 5.4, which corresponds to 0.013 <= Ω_{b}h^2_{100} <= 0.020.