The 2024 BBN baryon abundance update

Fuente: arXiv
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Main Author: Schöneberg, Nils
Format: Preprint
Published: 2024
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author Schöneberg, Nils
author_facet Schöneberg, Nils
contents We revisit the state of the light element abundances from big bang nucleosynthesis in early 2024 with particular focus on the derived baryon abundance. We find that the largest differences between the final baryon abundances are typically driven by the assumed Deuterium burning rates, characterized in this work by the underlying code. The rates from theoretical ab-initio calculations favor smaller baryon abundances, while experimentally-determined rates prefer higher abundances. Through robust marginalization over a wide range of nuclear rates, the recently released $\mathtt{PRyMordial}$ code allows for a conservative estimate of the baryon abundance at $Ω_b h^2 = 0.02218 \pm 0.00055$ (using PDG-recommended light element abundances) in $Λ$CDM and $Ω_b h^2 = 0.02196 \pm 0.00063$ when additional ultra-relativistic relics are considered ($Λ$CDM + $N_\mathrm{eff}$). These additional relics themselves are constrained to $ΔN_\mathrm{eff} = -0.14 \pm 0.21$ by light element abundances alone.
format Preprint
id arxiv_https___arxiv_org_abs_2401_15054
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The 2024 BBN baryon abundance update
Schöneberg, Nils
Cosmology and Nongalactic Astrophysics
We revisit the state of the light element abundances from big bang nucleosynthesis in early 2024 with particular focus on the derived baryon abundance. We find that the largest differences between the final baryon abundances are typically driven by the assumed Deuterium burning rates, characterized in this work by the underlying code. The rates from theoretical ab-initio calculations favor smaller baryon abundances, while experimentally-determined rates prefer higher abundances. Through robust marginalization over a wide range of nuclear rates, the recently released $\mathtt{PRyMordial}$ code allows for a conservative estimate of the baryon abundance at $Ω_b h^2 = 0.02218 \pm 0.00055$ (using PDG-recommended light element abundances) in $Λ$CDM and $Ω_b h^2 = 0.02196 \pm 0.00063$ when additional ultra-relativistic relics are considered ($Λ$CDM + $N_\mathrm{eff}$). These additional relics themselves are constrained to $ΔN_\mathrm{eff} = -0.14 \pm 0.21$ by light element abundances alone.
title The 2024 BBN baryon abundance update
topic Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2401.15054