• DOI:10.1088/0004-637X/781/1/31
• Corpus ID: 34867799

Precision measures of the primordial abundance of deuterium

@article{Cooke2014PrecisionMO,
  title={Precision measures of the primordial abundance of deuterium},
  author={Ryan J. Cooke and Max Pettini and Regina A. Jorgenson and Michael T. Murphy and Charles C. Steidel University of California and Santa Cruz and Institute of Radio Astronomy and University of Cambridge and Kavli Institute for Cosmology and Institute for Astronomy and University of Hawaii and Swinburne University of Technology and California Institute of Technology.},
  journal={The Astrophysical Journal},
  year={2014},
  volume={781},
  pages={31}
}

• R. Cooke, M. Pettini, +10 authors C. I. O. Technology.
• Published 14 August 2013
• Physics
• The Astrophysical Journal

We report the discovery of deuterium absorption in the very metal-poor ([Fe/H] = –2.88) damped Lyα system at z_abs = 3.06726 toward the QSO SDSS J1358+6522. On the basis of 13 resolved D I absorption lines and the damping wings of the H I Lyα transition, we have obtained a new, precise measure of the primordial abundance of deuterium. Furthermore, to bolster the present statistics of precision D/H measures, we have reanalyzed all of the known deuterium absorption-line systems that satisfy a set of strict criteria. We have adopted a blind analysis strategy (to remove human bias) and developed a software package that is specifically designed for precision D/H abundance measurements. For this reanalyzed sample of systems, we obtain a weighted mean of (D/H)_p = (2.53 ± 0.04) × 10^–5, corresponding to a universal baryon density 100 Ω_b, 0 h^2 = 2.202 ± 0.046 for the standard model of big bang nucleosynthesis (BBN). By combining our measure of (D/H)p with observations of the cosmic microwave background (CMB), we derive the effective number of light fermion species, N eff = 3.28 ± 0.28. We therefore rule out the existence of an additional (sterile) neutrino (i.e., N_eff = 4.046) at 99.3% confidence (2.7σ), provided that the values of N eff and of the baryon-to-photon ratio (η_10) did not change between BBN and recombination. We also place a strong bound on the neutrino degeneracy parameter, independent of the 4He primordial mass fraction, Y P: ξD = +0.05 ± 0.13 based only on the CMB+(D/H)_p observations. Combining this value of ξD with the current best literature measure of Y P, we find a 2σ upper bound on the neutrino degeneracy parameter, |ξ| ≤ +0.062.