Testing consistency of ${\Omega }_b{h}^2$ in the Planck data

Abstract

We find that the cosmic microwave background temperature and polarization power spectra measurements from Planck constrain the parameter ${\Omega }_b{h}^2$ mostly through: A) the amplitude of Thomson scattering and B) a factor that ensures Thomson scattering does not violate momentum conservation of the baryon-photon fluid. This allows us to obtain two distinct but comparably strong constraints on ${\Omega }_b{h}^2$ from the Planck data alone. They are consistent, showing robustness of the Planck ${\Omega }_b{h}^2$ constraint. We can alternatively rephrase these constraints as A) the change of the Thomson scattering cross section since recombination is less than $\sim 2\%$ and B) momentum during recombination is conserved to better than $\sim 2\%$ by Thomson scattering. Decoupling the eight various ways in which ${\Omega }_b{h}^2$ affects the Planck data leads to $H_0$ only slightly higher than in the standard analysis, $(68.3\pm 1.6)km/s/Mpc$. The overall consistency of all ${\Omega }_b{h}^2$ constraints does not suggest any problem with the standard cosmological model.

arXiv comment7 pages, 4 figures. Accepted version + added missing reference

References in corpus (15)

• Efficient Computation of CMB anisotropies in closed FRW models
• Cosmological parameters from CMB and other data: a Monte-Carlo approach
• A Line of Sight Approach to Cosmic Microwave Background Anisotropies
• Large Magellanic Cloud Cepheid Standards Provide a 1% Foundation for the Determination of the Hubble Constant and Stronger Evidence for Physics Beyond LambdaCDM
• Cosmological Perturbation Theory in the Synchronous and Conformal Newtonian Gauges
• Cosmological Perturbation Theory in the Synchronous vs. Conformal Newtonian Gauge
• The Hubble Hunter's Guide
• A New Calculation of the Recombination Epoch
• One percent determination of the primordial deuterium abundance
• Accurate halo-model matter power spectra with dark energy, massive neutrinos and modified gravitational forces
• Lensed CMB power spectra from all-sky correlation functions
• Updated fundamental constant constraints from Planck 2018 data and possible relations to the Hubble tension
• Photons and Baryons before Atoms: Improving the Tight-Coupling Approximation
• Testing cosmological models and understanding cosmological parameter determinations with metaparameters
• Baryon Physics and Tight Coupling Approximation in Boltzmann Codes

Cited by in corpus (5)

• Consistency tests of $\Lambda$CDM from the early integrated Sachs-Wolfe effect: Implications for early-time new physics and the Hubble tension
• Early-Universe-Physics Insensitive and Uncalibrated Cosmic Standards: Constraints on ${\Omega }_{\mathrm{m}}$ and Implications for the Hubble Tension
• Multidimensionality of the Hubble tension: the roles of ${\Omega }_m$ and ${\omega }_c$
• Investigating the Hubble Constant Tension -- Two Numbers in the Standard Cosmological Model
• Deconstructing the Planck TT Power Spectrum to Constrain Deviations from $\Lambda$CDM