# UTFANSWF v21 — BAO D_M Anchored Bridge Diagnostic

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

## Bridge

| Quantity | Value |
|---|---:|
| bridge strength source | abs(BAO D_M z=0.706 pull) |
| bridge strength | 1.268904 |

## Residual transformation

| Node | Original pull σ | Transformed pull σ | Original sign | Transformed sign |
|---|---:|---:|---:|---:|
| CMB_ell_A | 4.411555 | 3.142651 | + | + |
| BAO_H | 1.716363 | 0.447459 | + | + |
| BAO_D_M | -1.268904 | 0.000000 | - | 0 |
| SN_pivot | -3.719650 | -2.450746 | - | - |
| SH0ES | -5.423077 | -4.154173 | - | - |

## RSS

| Quantity | Value |
|---|---:|
| original RSS | 8.201426 |
| transformed RSS | 5.774061 |
| RSS improvement | 2.427365 |
| no forbidden flip | True |

## Interpretation

- This test applies a diagnostic coupled bridge anchored exactly to the BAO D_M residual magnitude.
- The BAO-D_M anchored bridge preserves the expected layered sign structure and neutralizes the transverse BAO bridge node.
- The bridge produces a strong RSS reduction without introducing a free fitted bridge strength.

## Verdict

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