pionNeutralMass_MeV
plain-language theorem explainer
Neutral pion mass is fixed at 134.9768 MeV from PDG 2024. Hadron mass modelers and Recognition Science ladder calculations cite this anchor when computing electromagnetic splittings against the charged pion. The entry is a direct numerical definition with no computation or lemmas.
Claim. The neutral pion mass is $134.9768$ MeV.
background
Pion masses arise in Recognition Science from quark-antiquark binding on the phi-ladder and explicit chiral symmetry breaking. The module sets the neutral pion (ūu-dd̄ state) at rung 12 relative to coherence energy, with the GMOR relation linking mass squared to quark masses and condensate. This definition supplies the PDG 2024 numerical value used for all subsequent difference and ratio calculations in the module.
proof idea
Direct definition that assigns the constant 134.9768 with no lemmas or tactics.
why it matters
Supplies the neutral reference for downstream theorems establishing that the charged pion is heavier, the electromagnetic mass difference is 4.6 MeV, and the relative difference is 3.4 percent. It anchors the phi-ladder prediction m_π/m_e ≈ 273 and the rung-12 placement inside the eight-tick octave. The entry closes the experimental input for P-013 derivations.
Switch to Lean above to see the machine-checked source, dependencies, and usage graph.