Observable detail · COS

Baryon density \(\Omega_b h^2\)

Prediction / mechanism	Inherits Planck/BBN value \(\Omega_b h^2 = 0.0224 \pm 0.0001\); SM tautology under constant-\(P_0\).
Measured	Planck 2018 PR3 \(\Omega_b h^2 = 0.02237 \pm 0.00015\).
Residual / status	HIT — SM tautology
Status	HIT
Source paper	DCT-COS-01

Mechanism

Background Friedmann inherits \(\Omega_b\) from CMB + BBN concordance.

Derivation

The derivation chain follows the cluster paper DCT-COS-01 and reduces to the canonical DCT constants (\(P_0 = 0.851\), \(\omega_0 = 50{,}037\), \(c_{BD} = 138{,}189\), master identity \(2\omega_0 + 3 = c_{BD} \cdot P_0^2 = 100{,}077\)). See the cluster paper for the full multi-line derivation.

Methodology

Domain	Cosmology (COS)
Input data source	See "References" below for the canonical public-archive citation.
Measurement procedure	The measured value used here is the most recent peer-reviewed central value plus 1σ uncertainty from the cited reference.
Acceptance threshold	HIT: residual within 1σ of measurement. SOFT: directional agreement within bracketing range. OPEN: untested or unresolved.
Falsification threshold	MISS: prediction excluded at ≥3σ by the canonical measurement under the corpus-canonical (constant-\(P_0\)) treatment.
Current status	See verdict pill above.

Python verification

Verification script: cmb_analysis.py. Run with python3 cmb_analysis.py to reproduce the canonical DCT result against the public-archive measurement source listed below.

Cross-references

Related observables: bbn-abundances · planck-cmb-tt.

Aggregate views: /predictions/ · /scorecard/ · /empirical/ · /outstanding-problems/.

Audit notes

This sub-page is part of the post-build-out of the observable archive (see the observable index). Verdict reflects the corpus-canonical (constant-\(P_0\)) treatment. The cluster-paper deep-link above (DCT-COS-01) is the canonical source of the derivation chain.

References

Planck Collaboration 2020
Source paper: DCT-COS-01

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