Primordial nucleosynthesis redux

Walker, T. W.; Steigman, Gary; Schramm, David N.; Olive, Keith A.; Kang, Ho Shik

doi:10.1086/170255

Cited by 850 publications

(834 citation statements)

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“…(11). The result found in [1] was N ν < 3.3. The methods for deriving N ν have since been refined incorporating a more statistical meaning to the bound.…”

Section: Constraints On N νmentioning

confidence: 81%

“…The literature on light element abundance measurements is large, and is well-reviewed in, e.g., references [1,21,22]. Here we will give only a brief summary of the current best abundances for each light isotope, with emphasis on new developments, particularly the possible detection of D/H in quasar absorption line systems (QSOALS).…”

Section: Datamentioning

confidence: 99%

“…In fact, it has been common [1] to express (by means of a fit) the 4 He mass fraction as a function of η 10 , N ν , and the neutron meanlife. For example, near η 10 = 2 and N ν = 3, we have,…”

Section: Constraints On N νmentioning

confidence: 99%

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Model independent predictions of big bang nucleosynthesis from He and Li: consistency and implications

et al. 1996

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We examine in detail how BBN theory is constrained, and what predictions it can make, when using only the most model-independent observational constraints. We avoid the uncertainties and model-dependencies that necessarily arise when solar neighborhood D and 3 He abundances are used to infer primordial D and 3 He via chemical and stellar evolution models. Instead, we use 4 He and 7 Li, thoroughly examining the effects of possible systematic errors in each. Via a likelihood analysis, we find near perfect agreement between BBN theory and the most model-independent data. Given this agreement, we then assume the correctness of BBN to set limits on the single parameter of standard BBN, the baryon-to-photon ratio, and to predict the primordial D and 3 He abundances. We also repeat our analysis including recent measurements of D/H from quasar absorption systems and find that the near perfect agreement between theory and observation of the three isotopes, D, 4 He and 7 Li is maintained. These results have strong implications for the chemical and stellar evolution of the light elements, in particular for 3 He. In addition, our results (especially if the D/H measurements are confirmed) have implications for the stellar depletion of 7 Li. Finally, we set limits on the number N ν of neutrino flavors, using an analysis which carefully and systematically includes all available experimental constraints. The value N ν = 3.0 fits best with BBN and a 95% CL upper limit of N ν < ∼ 4 is established.

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“…(11). The result found in [1] was N ν < 3.3. The methods for deriving N ν have since been refined incorporating a more statistical meaning to the bound.…”

Section: Constraints On N νmentioning

confidence: 81%

Section: Datamentioning

confidence: 99%

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Model independent predictions of big bang nucleosynthesis from He and Li: consistency and implications

et al. 1996

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“…The spectra were obtained in 5 exposures covering 3890 -7450Å on July 31 and Aug. 1,1994. We used a Textronix 2303x2048 CCD with 2x2 pixel on chip binning.…”

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confidence: 99%

Cosmological baryon density derived from the deuterium abundance at redshift z = 3.57

Tytler

Fan

Burles

1996

Nature

304

281

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The primordial ratio of the number of deuterium to hydrogen nuclei (D/H) created in big bang nucleosynthesis is the most sensitive measure of the cosmological baryon to photon ratio and the cosmological density of baryons Ω b (1-5). In the interstellar medium (ISM) of our Galaxy D/H = 1.6 ± 0.1 × 10 −5 (6), which places a strict lower limit on the primordial abundance, because stars reduce the proportion of D in the ISM. Quasar absorption systems (QAS) should give definitive measurements of the primordial D because they can sample metal-poor gas at early epochs where the destruction of D should be negligible. A probable measurement of a high abundance ratio was reported in one QAS: D/H ≈ 24 × 10 −5 (7,8). Here we report a measurement of low D/H = 2.3 ×10 −5 , in another QAS, which is consistent with D/H in the ISM, with models of Galactic chemical evolution, (9,10), and with earlier data (7,8) provided that D line is strongly contaminated. We have internal consistency checks, and believe that this is the first direct measurement of a primordial abundance ratio. It provides the most accurate measurement of the baryon density: a high value of Ω b = 0.05, assuming a Hubble constant H 0 = 70 km s −1 Mpc −1 .Deuterium is rarely seen in QAS because the associated hydrogen is usually distributed over a wide range of velocities and its absorption covers deuterium. We selected QSO 1937-1009 because we found that the absorption system at z = 3.572 showed unusually weak metal lines in low resolution spectra, which we took to indicate that the gas was distributed in one or two narrow velocity components (11). We obtained optical spectra of QSO 1937-1009 (z em = 3.78, V ≃ 17.5) with the HIRES echelle spectrograph (12) on the W. M. Keck 10-m telescope. The high quality spectra make this amongst the best characterized QAS, and show strong absorption at the expected position of the D Lyα line and weak but highly significant absorption at D Lyβ .The weak metal lines in the system, C II, C IV, Si II, and Si IV, appear to have the same profiles, which are adequately described by two components separated by 15 km s −1 .

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“…In the past, δN ν has been argued to be 0.3 or even smaller as 0.04 [12]. However, although claimed to be quite conservative, more careful recent analyses do not exclude even δN ν = 1.5 [13].…”

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confidence: 99%

Cosmological implications of radiatively generated axion scale

1997

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We study cosmological implications of supersymmetric axion models in which the axion scale is generated radiatively. Such models lead to the so-called thermal inflation and subsequent reheating should be constrained not to yield a too large axion energy density at the time of nucleosynthesis. We examine how plausible it is that this nucleosynthesis constraint is satisfied for both hadronic and Dine-Fischler-Srednicki-Zhitnitskii type axion models. Baryogenesis and the possibility for raising up the cosmological upper bound on the axion scale in thermal inflation scenario are also discussed.

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Primordial nucleosynthesis redux

Cited by 850 publications

References 0 publications

Model independent predictions of big bang nucleosynthesis from He and Li: consistency and implications

Model independent predictions of big bang nucleosynthesis from He and Li: consistency and implications

Cosmological baryon density derived from the deuterium abundance at redshift z = 3.57

Cosmological implications of radiatively generated axion scale

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