Geometric Strain and the Proton Radius Puzzle: A Zero-Parameter Resolution

The proton radius puzzle—the persistent 4% discrepancy between electronic (0.8751 fm) and muonic (0.84087 fm) measurements of the proton charge radius—has remained unresolved since 2010 despite extensive theoretical and experimental effort. I propose that this discrepancy is not an experimental artifact or evidence of new physics, but rather a direct manifestation of geometric strain: the elastic deformation of measurement boundaries by probes of different information density. Defining channel stiffness as proportional to particle mass and treating the fine structure constant α as the elastic modulus of the vacuum geometry, I derive a universal strain law: Δr/r = α × ln(m_μ/m_e). This yields a predicted discrepancy of 3.89%, matching the experimental value of 3.91% to within 0.5%. The result suggests that the ‘puzzle’ reflects not missing physics but an unrecognized property of measurement itself: observers with different information density necessarily perceive different geometric boundaries.