# LIB2-305 — Supply the missing QCD flip energy in the neutron–proton splitting

- class: OPEN · review_state: IN_REVIEW · house_tier: not yet assigned
- labels as printed: math_status None · attachment None · scorecard tier word none (PDF p.None)
- basis: {"pdf_sha256_prefix": "b64ddcd9e16a6dcd", "release": "Rev33.1_S369"}

## Statement

Can a QCD flip energy complete the neutron–proton mass-difference calculation alongside the existing Coulomb/QED contribution?

## Caution

No neutron–proton mass prediction or continuous isospin dynamics follows from the registered parity alone.

## Primary source

Paper 9, §9, Isospin sector: unpriced neutron–proton difference, PDF p.138: "The neutron–proton mass difference mn − mp = 1.2933 MeV is unpriced: the framework carries the QED half (Coulomb, with α external) and no QCD half (mu = md at constituent level; the e7 flip carries no energy), so without a flip energy its sign comes out wrong (s1129)."

## Machine

- url: /library-v2/LIB2-305/
- content_sha256: d3679502657fdfa424f5dec97e1b95ab8163e18668cf54e29001f133b8714e01
- candidate_ids: C2-130

## Freshness

- BUILD_STAMP S371a · 2026-09-26T22:53Z · master 01d1a5873ede42f5 · cut 9dcc6ce9a8ee3e02
- Declared volatile fields (R36): BUILD_STAMP