Nucleosynthesis Predictions and High-Precision Deuterium Measurements

Abstract

Abstract:Two new high-precision measurements of the deuterium abundance from absorbers along the line of sight to the quasar PKS1937-1009 were presented. The absorbers have lower neutral hydrogen column densities (N(HI) ≈ 18 cm −2 ) than for previous high-precision measurements, boding well for further extensions of the sample due to the plenitude of low column density absorbers. The total high-precision sample now consists of 12 measurements with a weighted average deuterium abundance of D/H = 2.55 ± 0.02 × 10 −5 . The sample does not favour a dipole similar to the one detected for the fine structure constant. The increased precision also calls for improved nucleosynthesis predictions. For that purpose we have updated the public AlterBBN code including new reactions, updated nuclear reaction rates, and the possibility of adding new physics such as dark matter. The standard Big Bang Nucleosynthesis prediction of D/H = 2.456 ± 0.057 × 10 −5 is consistent with the observed value within 1.7 standard deviations.

Electroweak baryogenesis from temperature-varying couplings

“…However, it fails to explain a few critical phenomena, including one which is crucial to our existence, namely the origin of the matter-antimatter asymmetry in the universe. Through cosmological observations from the Cosmic Microwave Background (CMB) [1] and Big Bang Nucleosynthesis (BBN) [2], this asymmetry is measured to be Y B = n B s ∼ 10 −10 .…”

Fixing the big bang cosmological problem

“…All odds are that such a resonant state does not exist. [22,23], compatible with 100Ω b h 2 (BBN) = 2.225 ± 0.016 inferred from the measurements of the cosmic microwave background [3], (c) 3 He abundance is taken from Ref. [24], and (d) the lithium abundance is taken from Ref.…”

“…The mass fraction for 4 He, historically denoted by Y p , is taken from Ref. [18], (b) the deuterium abundance D/H = (2.527 ± 0.03) × 10 −5 [22,23], compatible with 100Ω b h 2 (BBN) = 2.225 ± 0.016 inferred from the measurements of the cosmic microwave background [3], (c) the 3 He abundance is taken from Ref. [24], and (d) the lithium abundance is taken from Ref.…”

Constraints on Primordial Black Holes From Big Bang Nucleosynthesis Revisited

“…• We use the deuterium-to-hydrogen measurement of (D/H) p = (2.53 ± 0.04) × 10 −5 , based on the observation of four damped Lyman-alpha systems [36] (see also, Ref. [37]). Note that the uncertainties quoted for this result are significantly smaller than those associated with previous measurements, allowing us to place constraints that are significantly more stringent than those presented in Refs.…”