# UTFANSWF v21 — Row 20 BAO Bridge Probe

**Context:** DIAGNOSTIC_NON_GATING. No physics, thresholds, datasets, parameters, or gate verdicts changed.

## BAO DM/H nodes

| Slice | z | observable | data | theory | residual | pull sigma | chi2 |
|---|---:|---|---:|---:|---:|---:|---:|
| D_M z=0.510 | 0.510 | D_M | 2007.973214 | 1981.016373 | 26.956841 | 1.083420 | 1.173799 |
| H z=0.510 | 0.510 | H | 92.788967 | 89.790118 | 2.998849 | 1.647567 | 1.685407 |
| D_M z=0.706 | 0.706 | D_M | 2564.085107 | 2597.825563 | -33.740456 | -1.268904 | 1.610117 |
| H z=0.706 | 0.706 | H | 104.271594 | 101.200355 | 3.071238 | 1.716363 | 5.829909 |

## Bridge drift z=0.510 → z=0.706

| Observable | low pull | high pull | pull drift | low residual | high residual | residual drift |
|---|---:|---:|---:|---:|---:|---:|
| H | 1.647567 | 1.716363 | 0.068796 | 2.998849 | 3.071238 | 0.072389 |
| D_M | 1.083420 | -1.268904 | -2.352324 | 26.956841 | -33.740456 | -60.697297 |

## z=0.706 projection check

| Quantity | Value |
|---|---:|
| D_M pull | -1.268904 |
| H pull | 1.716363 |
| H minus D_M pull gap | 2.985267 |
| combined z=0.706 chi2 | 7.440026 |

## Interpretation

- BAO bridge probe tests whether the z=0.706 bridge slice follows CMB, bends toward SN/SH0ES, or carries its own DM/H projection tension.
- At z=0.706, H(z) and D_M pull in opposite signs, indicating radial/transverse BAO projection tension.
- The z=0.706 radial/transverse pull gap is large enough to mark the bridge as internally stressed.
- BAO z=0.706 stress is much smaller than SH0ES overlay stress, so BAO does not carry the solution to H0≈73.

## Verdict

BAO_bridge_geometry_probe_complete; diagnostic only; no physics, thresholds, datasets, parameters, or gate verdicts changed.
