Equal u, d Quark Mass and Diquark, Nucleon Structure

Author(s)

Abstract
The known masses of 6 mesons, π^±, K^±, D⁰, Φ(1020), J/Ψ, and Y(1S), chosen for their purity in their quark contents, have been inserted into the meson mass formula in SSI, scalar strong interaction hadron theory, to fix the masses of the five quarks, u, d, s, c, and b and a constant d_m0 in that formula. The u and d quark masses were found to be nearly the same, 0.5891243±1.7×10^-5 GeV. This discovery revises our earlier conception that the d quark is about 2 MeV heavier than the u quark, obtained using 6 other mesons as input. Applied to nucleon, the strong interaction parts in the proton and neutron have also to be the same. But the proton charge is expected to contribute its Coulomb energy to its strong interaction mass to become heavier than the neutron mass. This result however contradicts data. This problem appears to be related to the diquark-quark structure of the nucleon. The diquark, considered as a point particle hitherto in SSI, has now a small extension, < 0.45 fm here, due to Coulomb repulsion. This force generates a “hidden” charge mass to be subtracted from the common strong interaction mass. Since this extra charge mass is greater for the uu diquark than for dd, the proton is lighter. A coarse estimate in SSI led to some qualitative values about 31 to 56 % smaller than the measured 1.293 MeV.

Keywords
scalar strong interaction hadron theory SSI, ground state mesons, meson mass formula, equality of predicted u and d mass, “arrow” model of nucleon, Coulomb repulsion in diquark, “rod” like diquark, virtual charge mass, nucleon mass difference.

Cite this paper
F. C. Hoh, Equal u, d Quark Mass and Diquark, Nucleon Structure , SCIREA Journal of Physics. Volume 11, Issue 3, June 2026 | PP. 158-168. 10.54647/physics140726

References