What question did this study set out to answer?

To analyze CMB shift parameters R and l_a within the framework of the U-Cell Model and compare results with ΛCDM.

April 5, 2026Open Access

The U-Cell Model and the CMB Acoustic Scale: Self-Consistent Analysis of the lₐ Constraint

Key Points

To analyze CMB shift parameters R and l_a within the framework of the U-Cell Model and compare results with ΛCDM.
Conducted a numerical analysis of Planck 2018 CMB shift parameters for U-Cell Model.
Applied Eisenstein–Hu approximations for both UCM and ΛCDM models.
Calculated the difference in l_a between UCM and ΛCDM.
The UCM–ΛCDM difference in l_a is 1.8σ, smaller than previous estimate of 4.2σ.
Achieved full consistency with l_a=301.471 at Omega_b h²=0.02246.
The results are 0.6σ from Planck and 0.5σ from BBN, providing new predictions for future observatories.

Abstract

A self-consistent numerical analysis of the Planck 2018 CMB shift parameters (R, lₐ) for the U-Cell Model (UCM) parameters (Omegaₘ=0. 3166, w=−1) using identical Eisenstein–Hu approximations for both UCM and ΛCDM. The UCM–ΛCDM difference in lₐ is 1. 8σ — a factor 2. 3 smaller than a previous naive estimate of 4. 2σ. Full consistency with lₐ=301. 471 is achieved at Omegab h²=0. 02246, which is 0. 6σ from Planck and 0. 5σ from BBN. This value constitutes a new falsifiable UCM prediction testable by CMB-S4 and Simons Observatory.

The U-Cell Model and the CMB Acoustic Scale: Self-Consistent Analysis of the lₐ Constraint

Key Points

Abstract

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