Improved Constraints on Primordial Gravitational Waves using Planck, WMAP, and… (SRC-BICEP-KECK-2021)

Improved Constraints on Primordial Gravitational Waves using Planck, WMAP, and BICEP/Keck Observations through the 2018 Observing Season

Ade, P. A. R.; Ahmed, Z.; et al. (BICEP/Keck Collaboration) · 2021

AI-verified citationSRC-BICEP-KECK-2021

identifier / locator

Physical Review Letters 127(15): 151301. DOI: 10.1103/PhysRevLett.127.151301

verification note

DOI and bibliographic details confirmed via Crossref.

reliability notes

The current observational frontier for primordial tensor B-modes (r < 0.036 at 95% CL): no detection yet — the forward-looking discriminator between inflationary ΛCDM and non-inflationary scenarios like CCC remains open.

Evidence drawn from this source

Qualifies· moderateCCC-E021

what the source states: The combined BICEP/Keck, Planck, and WMAP analysis through the 2018 observing season constrains the tensor-to-scalar ratio to r < 0.036 at 95% confidence, with no detection of primordial gravitational-wave B-modes.
what we infer: Qualifies the inflationary steelman rather than supporting CCC: the one signature that would evidence an inflationary era in our own aeon directly remains unseen, so the discriminating measurement between the two frameworks (CCC-R003) is still open in both directions. Recorded symmetrically: a future detection would create a signal CCC has no mechanism for; continued nulls constrain inflationary models without confirming CCC.
limitations: Many viable inflation models predict r below current sensitivity, so the null does not currently damage the steelman.