# UTFANSWF Result 04 — Proton-Origin / isoQCD Nucleon Mass Closeout

**Date:** 2026-08-16  
**Verdict:** `PASS_TARGET_ISOLATED_ISOQCD_NUCLEON_MASS_CLOSURE`  
**Publication policy:** Ron updates the final PDF manually. No `main.tex` or PDF was modified.

## Frozen forward result

- Model-averaged isoQCD nucleon mass: **941.223 ± 35.184 MeV**
- AICc-preferred model: **939.101 MeV**
- Forward SHA-256: `3d3058e25117f4b8fe7c97dd124bcdc35e6b7ce1a644a8c568d40b0ac15fb921`
- Proton/neutron holdout used in forward fit: **No**

## Input boundary

The closed claim begins from independent Standard-Model/QCD inputs, not from a first-principles derivation of the entire flavor sector:

- frozen UTFANSWF `alpha_s(M_Z)=0.1184`;
- hardened `Lambda_MSbar^(3)=339.796 ± 4.2 MeV`;
- independent ALPHA RGI quark masses `M_ud=4.70 MeV`, `M_s=127.0 MeV`;
- 24 external CLS `N_f=2+1` production ensembles at five lattice spacings;
- internal continuum/chiral/model-average reconstruction;
- no proton or neutron mass used to select the forward result.

## Stability

- Leave-one-ensemble result range: **936.73–947.44 MeV**.
- 1% mass-renormalization stress range: **930.49–947.42 MeV**.
- Same-CLS published continuum analysis: **941.7 MeV**, only **0.477 MeV** from this reconstruction (analysis cross-check, not independent ensemble validation).

## What closes

The proton-origin project closes at the standard QCD input boundary: **QCD dynamics generates the nucleon matter scale from upstream SM/QCD parameters without using the nucleon mass as a solve target.**

## What remains separate

1. **Flavor-Origin:** deriving light/strange Yukawa amplitudes from UTFANSWF itself. Existing v22-native routes were tested and do not uniquely close this.
2. **Physical charged proton:** a full `m_u != m_d` + QED production calculation. The absolute split from isoQCD is convention/scheme dependent, so no arbitrary correction was appended.

These are distinct extensions and are not hidden blockers of the isoQCD nucleon-mass closure.

## Claim discipline

Do **not** claim that current v22 derives all quark Yukawas or that this is a pristine first-time blind proton prediction. A defensible label is:

> **Result 04 candidate — target-isolated isoQCD nucleon / matter-scale closure.**
