# UTFANSWF Research Item 05 — Full Proton QCD+QED Completion

Date: 2026-08-17/18 (America/New_York)

## Production isolation
- Frozen v23 canonical 18/18 PASS bundle was not modified.
- Protected `main.tex` and `main.pdf` were not modified.

## Starting point
Row 29 closes only the isospin-symmetric N_f=2+1 QCD nucleon mass:
- `M_N_isoQCD = 941.2231331333769 MeV`
- `sigma = 35.184029612232145 MeV`
- `m_u = m_d`, no QED.

A physical charged-proton completion requires, schematically,

`M_p = M_N_isoQCD + deltaM_p_SIB + deltaM_p_QED + higher orders`.

A source-complete first-order response therefore needs compatible, renormalized inputs for the up/down mass splitting and strong response, plus the electromagnetic coupling and proton QED response.

## Internal response machinery
The archived symmetric-state program has the correct architecture:

`M_n - M_p = g_S (m_d-m_u) + alpha K_EM + ...`

- Feynman-Hellmann strong-response engine preflight: PASS as machinery, but its tiny-lattice coefficient is not a physical/renormalized `g_S`.
- QED response engine preflight: PASS for even/quadratic response infrastructure, but FAIL for physical electromagnetic sign/coefficient extraction on the tiny lattice.

No toy coefficient is promoted.

## Dependency audit
Required internal quantities:
- isoQCD nucleon mass: AVAILABLE (Row 29).
- unique first-generation `m_d-m_u`: NOT CLOSED; Item 04 no-go.
- physical/renormalized strong response `g_S`: NOT AVAILABLE; engine preflight only.
- physical electromagnetic coupling: NOT CLOSED; Item 01 blind-alpha closeout remains blocked.
- physical/renormalized QED response `K_EM`: NOT AVAILABLE; engine preflight only.

The manuscript's old `-0.76 MeV * alpha/alpha0` electromagnetic splitting is not admissible as a blind completion because it is normalized to measured `alpha0`.

## External methodology audit
Primary lattice literature confirms that the desired calculation class is physically well-defined:
- Borsanyi et al., arXiv:1406.4088: fully dynamical QCD+QED with nondegenerate quarks; physical-coupling interpolation is part of the calculation.
- Romiti, arXiv:2203.04636: first-order QCD+QED/RM123 slopes evaluated in isoQCD; the calculation explicitly uses physical `alpha_EM` and experimental hadronic ratios to define/tune the physical point.
- de Divitiis et al., arXiv:1303.4896: general leading-isospin-breaking expansion in `m_d-m_u` and `alpha_EM`.

These validate the response architecture but do not provide a blind UTFANSWF closure of the missing internal inputs.

## Verdict
`BLOCKED_PRODUCTION_QCDQED_RESPONSE__INTERNAL_ALPHA_AND_FLAVOR_BOUNDARIES_OPEN`

A conditional Standard-Model QCD+QED completion is viable in principle if physical alpha, quark masses, and production response coefficients are imported. That would be a conditional external-SM completion, not an internally derived blind UTFANSWF proton prediction.

## Production consequence
None. Row 29 remains correctly scoped as an isoQCD nucleon-mass closure. The frozen v23 18/18 PASS checkpoint remains untouched.
