Preprint Revisits Non-Additivity of Mass in Special Relativity, Reaffirming QCD Origin of Hadron Masses

Caruso deconstructs the common reading of E=mc² as direct mass-energy equivalence and derives non-additivity of mass from four-momentum conservation alone. In composite systems the total invariant mass differs from the sum of parts whenever internal potential energy is present. The analysis contrasts atomic nuclei, where binding energy reduces total mass, with hadrons, where confinement raises it.

Lattice QCD calculations and experimental parton distributions already quantify this: valence quarks account for under 5% of nucleon mass while gluon fields and sea quarks supply the rest. Caruso’s contribution is mainly conceptual, clarifying why the “missing mass” is not missing but stored as field energy.

The paper does not present new data or derivations beyond textbook special-relativistic kinematics applied to QCD. Its framing nevertheless underscores that everyday matter is an emergent phenomenon of strong-interaction dynamics rather than a simple sum of elementary masses.

Future high-precision lattice simulations and electron-ion collider measurements of gluon distributions will test the quantitative partition of mass between quarks and gluons to sub-percent accuracy.