# UTFANSWF v21 — Row 20 Bridge Origin Probe

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

## Bridge strength

| Quantity | Value |
|---|---:|
| best coupled bridge strength | 1.266000 |

## Candidate origin scales

| Rank | Candidate | Value | abs difference | relative error |
|---:|---|---:|---:|---:|
| 1 | BAO_DM_pull | 1.268904 | 0.002904 | 0.002289 |
| 2 | ell_A_minus_BAO_H_gap_half | 1.347596 | 0.081596 | 0.060549 |
| 3 | half_BAO_H_minus_DM_gap | 1.492633 | 0.226633 | 0.151835 |
| 4 | mean_BAO_abs_pull | 1.492633 | 0.226633 | 0.151835 |
| 5 | SH0ES_minus_SN_gap_half | 0.851713 | 0.414287 | 0.486416 |
| 6 | BAO_H_pull | 1.716363 | 0.450363 | 0.262394 |
| 7 | SN_pivot_half_abs | 1.859825 | 0.593825 | 0.319291 |

## Best match

```json
{
  "candidate": "BAO_DM_pull",
  "value": 1.2689039785507539,
  "bridge_strength": 1.266,
  "absolute_difference": 0.0029039785507538607,
  "relative_error": 0.0022885723426216737
}
```

## Interpretation

- This probe tests whether the best coupled bridge strength can be attributed to an existing residual geometry scale rather than treated as a new fitted parameter.
- The bridge strength is closest to a BAO bridge/projection scale, supporting a BAO-origin interpretation.
- The closest scale matches the bridge strength within 20%, which is sufficient for diagnostic-origin plausibility but not final proof.

## Verdict

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