Updated Big–bang Nucleosynthesis Compared to Wmap Results

Coc, A.; VANGIONI-FLAM, ELISABETH; Descouvemont, Pierre; Adahchour, Abderrahim; ANGULO, CARMEN

doi:10.1142/9789812702739_0002

Cited by 9 publications

(44 citation statements)

References 25 publications

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“…(Unless otherwise specified, we quote 1σ limits in text and tables, whereas the 2-dimensional figures show 2σ limits.) Figure 3 shows that the WMAP+SDSS allowed value of the baryon density ω b = 0.023 ± 0.001 agrees well with the latest measurements ω b = 0.022 ± 0.002 from Big Bang Nucleosynthesis [41][42][43]. It is noteworthy that the WMAP+SDSS preferred value is higher than the BBN preferred value ω b = 0.019 ± 0.001 of a few years ago [44], so the excellent agreement hinges on improved reaction rates in the theoretical BBN predictions [42] and a slight decrease in observed deuterium abundance.…”

Section: Figsupporting

confidence: 76%

Cosmological parameters from SDSS and WMAP

Tegmark¹,

Strauss²,

Blanton³

et al. 2004

Phys. Rev. D

3,494

1,835

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We measure cosmological parameters using the three-dimensional power spectrum P (k) from over 200,000 galaxies in the Sloan Digital Sky Survey (SDSS) in combination with WMAP and other data. Our results are consistent with a "vanilla" flat adiabatic ΛCDM model without tilt (ns = 1), running tilt, tensor modes or massive neutrinos. Adding SDSS information more than halves the WMAP-only error bars on some parameters, tightening 1σ constraints on the Hubble parameter from h ≈ 0.74−0.03 , on the matter density from Ωm ≈ 0.25 ± 0.10 to Ωm ≈ 0.30 ± 0.04 (1σ) and on neutrino masses from < 11 eV to < 0.6 eV (95%). SDSS helps even more when dropping prior assumptions about curvature, neutrinos, tensor modes and the equation of state. Our results are in substantial agreement with the joint analysis of WMAP and the 2dF Galaxy Redshift Survey, which is an impressive consistency check with independent redshift survey data and analysis techniques. In this paper, we place particular emphasis on clarifying the physical origin of the constraints, i.e., what we do and do not know when using different data sets and prior assumptions. For instance, dropping the assumption that space is perfectly flat, the WMAP-only constraint on the measured age of the Universe tightens from t0 ≈ 16.3 +2.3 −1.8 Gyr to t0 ≈ 14.1Gyr by adding SDSS and SN Ia data. Including tensors, running tilt, neutrino mass and equation of state in the list of free parameters, many constraints are still quite weak, but future cosmological measurements from SDSS and other sources should allow these to be substantially tightened.

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Section: Figsupporting

confidence: 76%

Cosmological parameters from SDSS and WMAP

Tegmark¹,

Strauss²,

Blanton³

et al. 2004

Phys. Rev. D

3,494

1,835

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“…Since then, deuterium has been steadily destroyed in stellar interiors by nuclear processes. Thus, its abundance compared to hydrogen, D/H, is a key measurement for studies of both cosmology and galactic chemical evolution (see, e.g., Vangioni-Flam, Coc, & Cassé 2000;Coc et al 2004). Although the evolution of the deuterium abundance seems to be qualitatively understood, important questions remain unanswered.…”

Section: Introductionmentioning

confidence: 99%

The Deuterium‐to‐Oxygen Ratio in the Interstellar Medium

Hébrard¹,

Moos²

2003

ApJ

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Because the ionization balances for H i, O i, and D i are locked together by charge exchange, the deuterium-to-oxygen ratio, D/O, is an important tracer for the value of the D/H ratio and for potential spatial variations in the ratio. As the D i and O i column densities are of similar orders of magnitude for a given sight line, comparisons of the two values will generally be less subject to systematic errors than comparisons of D i and H i, which differ by about 5 orders of magnitude. Moreover, D/O is additionally sensitive to astration, because as stars destroy deuterium, they should produce oxygen. We report here the results of a survey of D/O in the interstellar medium performed with the Far Ultraviolet Spectroscopic Explorer. We also compare these results with those for D/N. Together with a few results from previous missions, the sample totals 24 lines of sight. The distances range from a few to $2000 pc and log N(D i) from $13 to $16 cm À2 . The D/O ratio is constant in the local interstellar medium out to distances of $150 pc and NðD iÞ ' 1 Â 10 15 cm À2 , i.e., within the Local Bubble. In this region of the interstellar space, we find D=O ¼ ð3:84 AE 0:16Þ Â 10 À2 (1 in the mean). The homogeneity of the local D/O measurements shows that the spatial variations in the local D/H and O/H must be extremely few, if any. A comparison of the Local Bubble mean value with the few D/O measurements available for low-metallicity quasar sight lines shows that the D/O ratio decreases with cosmic evolution, as expected. Beyond the Local Bubble, we detected significant spatial variations in the value of D/O. This likely implies a variation in D/H, as O/H is known to not vary significantly over the distances covered in this study. Our data set suggests a present-epoch deuterium abundance below 1 Â 10 À5 , i.e., lower than the value usually assumed, around 1:5 Â 10 À5 .

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“…30 −0.27 × 10 −10 [11] from low-metallicity stars within the globular cluster NGC 6397, indicating if taken at face value, that there may be a problem in SBBN. This discrepancy may not be resolved by nuclear reaction rate uncertainties in the main lithium-producing reaction 3 He(α, γ) 7 Be [7] and only very unlikely due to uncertainties in the lithium-destroying reaction 7 Be(d, p)2 4 He [8]. It is conceivable, however, that it is due to other systematic uncertainties entering the inference of primordial 7 Li abundances, such as stellar astration of 7 Li in lowmetallicity stars, or imprecise determinations of stellar surface temperatures in these stars.…”

mentioning

confidence: 99%

Did something decay, evaporate, or annihilate during big bang nucleosynthesis?

Jedamzik

2004

Phys. Rev. D

246

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Results of a detailed examination of the cascade nucleosynthesis resulting from the putative hadronic decay, evaporation, or annihilation of a primordial relic during the Big Bang nucleosynthesis (BBN) era are presented. It is found that injection of energetic nucleons around cosmic time 10 3 sec may lead to an observationally favored reduction of the primordial 7 Li/H yield by a factor 2 − 3. Moreover, such sources also generically predict the production of the 6 Li isotope with magnitude close to the as yet unexplained high 6 Li abundances in low-metallicity stars. The simplest of these models operate at fractional contribution to the baryon density Ω b h 2 > ∼ 0.025, slightly larger than that inferred from standard BBN. Though further study is required, such sources, as for example due to the decay of the next-to-lightest supersymmetric particle into GeV gravitinos or the decay of an unstable gravitino in the TeV range of abundance ΩGh 2 ∼ 5 × 10 −4 show promise to explain both the 6 Li and 7 Li abundances in low metallicity stars.Big Bang nucleosynthesis has since long been known as one of the most precise and furthest back-reaching probes of cosmic conditions and the cosmic matter content of the early Universe. It thus, for example, has significantly contributed to the notion that a large fraction of matter in present-day galaxies is believed to be of non-baryonic nature as well as considerably limited some extensions of the standard model of particle physics. Paramount to having become such a useful tool of cosmology was and is, not only the examination of early synthesis of light elements in it's simplest standard version, but also in a variety of non-standard, alternative scenarios, relaxing a priori non-verified assumptions entering the calculations of a standard BBN (SBBN). Depending on the light element yields obtained in these latter scenarios, such calculations may then either favor a modified version of BBN, or strengthen the case for the SBBN. In either case, calculations of non-standard BBN may be used to place limits on the cosmic condition in the early Universe. In this spirit, technically advanced calculations of BBN including decaying particles during, or after BBN, an inhomogeneous baryon distribution, small-scale antimatter domains, neutrino degeneracy, or varying fundamental constants (for reviews cf.[1]), among others, have been performed over the years, rendering SBBN (also by the principle of Occam's razor) as our preferred scenario for BBN On the observational side significant advances have been made with the advent of high-resolution spectrographs on the Keck-and VLT-telescopes and the resulting capability to perform D/H abundance determinations of unprecedented accuracy in a few simple high-redshift quasar absorption line (QAL) systems. Furthermore an independent determination of the fractional contribution of baryons to the critical density, Ω b , from precision measurements of the cosmic microwave background radiation (CMB) by various balloon missions and the WMAP [2] sattelite has...

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Updated Big–bang Nucleosynthesis Compared to Wmap Results

Cited by 9 publications

References 25 publications

Cosmological parameters from SDSS and WMAP

Cosmological parameters from SDSS and WMAP

The Deuterium‐to‐Oxygen Ratio in the Interstellar Medium

Did something decay, evaporate, or annihilate during big bang nucleosynthesis?

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