Standard big bang nucleosynthesis and primordial CNO abundances after Planck

Coc, A.; Uzan, Jean‐Philippe; Vangioni, Elisabeth

doi:10.1088/1475-7516/2014/10/050

Cited by 151 publications

(190 citation statements)

References 95 publications

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“…The observed primordial abundances for D and 3,4 He agree well with the predictions of BBN model together with the precise WMAP cosmic baryon density while 7 Li abundance observations in metal poor halo stars are three times smaller than BBN+WMAP predictions [7]. This discrepancy is what is known as the 7 Li problem.…”

Section: The 7 LI Cosmological Problemsupporting

confidence: 78%

Indirect techniques for astrophysical reaction rates determinations

Hammache¹,

Oulebsir²,

Benamara³

et al. 2016

EPJ Web of Conferences

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Direct measurements of nuclear reactions of astrophysical interest can be challenging. Alternative experimental techniques such as transfer reactions and inelastic scattering reactions offer the possibility to study these reactions by using stable beams. In this context, I will present recent results that were obtained in Orsay using indirect techniques. The examples will concern various astrophysical sites, from the Big-Bang nucleosynthesis to the production of radioisotopes in massive stars.The main characteristics of the nuclear reactions involved in stellar nucleosynthesis is the low energy where they generally occur, between few keV to few MeV and at these energies the cross sections of these reactions are very small ranging from fbarn to hundreds of pbarn especially when it involves charged particles. This makes the direct measurements at stellar energies very difficult and often impossible. Hence direct measurement are usually performed at higher energies and then extrapolated down to stellar energies where the reactions occur. However the extrapolations can lead sometimes to wrong results when a possible very low energy resonance or the tail of a possible sub-threshold resonance are not taken into account. 201, 0 0 EPJ Web of Conferences

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Section: The 7 LI Cosmological Problemsupporting

confidence: 78%

Indirect techniques for astrophysical reaction rates determinations

Hammache¹,

Oulebsir²,

Benamara³

et al. 2016

EPJ Web of Conferences

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“…The 6 Li/ 7 Li error is dominated by the 22% uncertainty on 6 Li. The 7 Li abundance prediction is known at the 8% level [37] .…”

Section: Thermonuclear Reaction Rate and Astrophysical Implicationsmentioning

confidence: 99%

Big Bang 6 Li nucleosynthesis studied deep underground (LUNA collaboration)

Trezzi

Anders

Aliotta

et al. 2017

Astroparticle Physics

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a b s t r a c tThe correct prediction of the abundances of the light nuclides produced during the epoch of Big Bang Nucleosynthesis (BBN) is one of the main topics of modern cosmology. For many of the nuclear reactions that are relevant for this epoch, direct experimental cross section data are available, ushering the so-called "age of precision". The present work addresses an exception to this current status: the 2 H( α, γ ) 6 Li reaction that controls 6 Li production in the Big Bang. Recent controversial observations of 6 Li in metal-poor stars have heightened the interest in understanding primordial 6 Li production. If confirmed, these observations would lead to a second cosmological lithium problem, in addition to the well-known 7 Li problem. In the present work, the direct experimental cross section data on 2 H( α, γ ) 6 Li in the BBN energy range are reported. The measurement has been performed deep underground at the LUNA (Laboratory for Underground Nuclear Astrophysics) 400 kV accelerator in the Laboratori Nazionali del Gran Sasso, Italy. The cross section has been directly measured at the energies of interest for Big Bang Nucleosynthesis for the first time, at E cm = 80, 93, 120, and 133 keV. Based on the new data, the 2 H( α, γ ) 6 Li thermonuclear reaction rate has been derived. Our rate is even lower than previously reported, thus increasing the discrepancy between predicted Big Bang 6 Li abundance and the amount of primordial 6 Li inferred from observations.

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“…The effect of these re-evaluations can be seen between columns 2 and 3 in Table I, while columns 4 shows the effect of the re-evaluated reaction rates [5] for deuterium destruction (see § 3). Column 5 represent the results of a Monte Carlo calculation [5] as described in [7,9] but with these few new rates, to be compared with observations in Column 6. [5].…”

Section: Recent Resultsmentioning

confidence: 99%

Primordial Nucleosynthesis

Coc

2017

Proceedings of the 14th International Symposium on Nuclei in the Cosmos (NIC2016)

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Primordial or big bang nucleosynthesis (BBN) is now a parameter free theory whose predictions are in good overall agreement with observations. However, the 7 Li calculated abundance is significantly higher than the one deduced from spectroscopic observations. Most solutions to this lithium problem involve a source of extra neutrons that inevitably leads to an increase of the deuterium abundance. This seems now to be excluded by recent deuterium observations that have drastically reduced the uncertainty on D/H and also calls for improved precision on thermonuclear reaction rates.

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Standard big bang nucleosynthesis and primordial CNO abundances after Planck

Cited by 151 publications

References 95 publications

Indirect techniques for astrophysical reaction rates determinations

Indirect techniques for astrophysical reaction rates determinations

Big Bang 6 Li nucleosynthesis studied deep underground (LUNA collaboration)

Primordial Nucleosynthesis

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