Big-Bang Nucleosynthesis after Planck
By B. Fields, K. Olive, Tsung-Han Yeh, C. Young. Journal of Cosmology and Astroparticle Physics, 2019
352 citations recorded by the source corpus.
We assess the status of big-bang nucleosynthesis (BBN) in light of the final Planck data release and other recent developments, and in anticipation of future measurements. Planck data from the recombination era fix the cosmic baryon density to 0.9% precision, and now damping tail measurements determine the helium abundance and effective number of neutrinos with precision approaching that of astronomical and BBN determinations respectively. All three parameters are related by BBN . In addition, new high-redshift measurements give D/H to better precision than theoretical predictions, and new Li/H data reconfirm the lithium problem. We present new 7Be(n,p)7Li rates using new neutron capture measurements; we have also examined the effect of proposed changes in the d(p,γ)3He rates. Using these results we perform a series of likelihood analyses. We assess BBN/CMB consistency, with attention to how our results depend on the choice of Planck data, as well as how the results depend on the choice of non-BBN, non-Planck data sets. Most importantly the lithium problem remains, and indeed is more acute given the very tight D/H observational constraints; new neutron capture data reveals systematics that somewhat increases uncertainty and thus slightly reduces but does not essentially change the problem. We confirm that d(p,γ)3He theoretical rates brings D/H out of agreement and slightly increases 7Li new experimental data are needed at BBN energies. Setting the lithium problem aside, we find the effective number of neutrino species at BBN is Nν = 2.86 ± 0.15. Future CMB Stage\nobreakdash-4 measurements promise substantial improvements in BBN parameters: helium abundance determinations will be competitive with the best astronomical determinations, and Neff will approach sensitivities capable of detecting the effects of Standard Model neutrino heating of the primordial plasma.
Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics
View Paper: https://www.semanticscholar.org/paper/44f7de73413cddf8525cea49246b7e45d4198051
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Citations in the corpus
- The Dark Photon (2020, methodology): “This number is constrained by data on big bang nucleosynthesis (BBN) to be (Fields et al., 2020): Neff = 2.878± 0.278 .”
- Baryogenesis from the weak scale to the grand unification scale (2020, result): “74 × 10Ωbh(2) (Fields et al., 2020). One can always make a theory for a single number like ηB. Hence, to make progress it is important to develop a consistent picture of the evolution of the Universe that correlates the few available numbers in the framework of a theoretically consistent extension o”