AWhat changed
A 2015 joint analysis of BICEP2/Keck and Planck polarization maps found substantial Galactic dust contribution to the observed B-mode power and set a model-dependent limit r at pivot 0.05 per Mpc below 0.12 at 95% confidence. A later BICEP/Keck analysis adding 2016–2018 data and using WMAP and Planck maps reported r below 0.036 at 95% under its stated foreground and cosmological model.
Scientific scope
A 2015 joint analysis of BICEP2/Keck and Planck polarization maps found substantial Galactic dust contribution to the observed B-mode power and set a model-dependent limit r at pivot 0.05 per Mpc below 0.12 at 95% confidence. A later BICEP/Keck analysis adding 2016–2018 data and using WMAP and Planck maps reported r below 0.036 at 95% under its stated foreground and cosmological model. Both limits depend on foreground and cosmological assumptions. The 2021 baseline removes the earlier external dust spectral-index prior but retains a parametric foreground model, assumptions about lensing and synchrotron, and systematic uncertainties; its data overlap earlier analyses. The 2015 approximately seven-sigma lensing B-mode detection is not a primordial gravitational-wave detection. Neither upper limit establishes primordial tensor modes.
Evidence
The linked original works support the scoped statement and contribution attribution. WRS has not independently replayed experiments or reconstructed a full mathematical proof. Both limits depend on foreground and cosmological assumptions. The 2021 baseline removes the earlier external dust spectral-index prior but retains a parametric foreground model, assumptions about lensing and synchrotron, and systematic uncertainties; its data overlap earlier analyses. The 2015 approximately seven-sigma lensing B-mode detection is not a primordial gravitational-wave detection. Neither upper limit establishes primordial tensor modes.
Contributors
- The named authors in the research record · SCIENCE: These are the listed authors of the cited contribution sources. Paper authorship does not quantify individual effort. An incomplete list is explicitly marked; same names are not automatically merged.
- A Joint Analysis of BICEP2/Keck Array and Planck Data
- BICEP / Keck XIII: Improved Constraints on Primordial Gravitational Waves using Planck, WMAP, and BICEP/Keck Observations through the 2018 Observing Season
Provisional WRS assessment, edition 2026-10-28.1. Independent expert calibration is pending. This grade does not certify correctness or assign ownership.
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