Hadron masses in cavity quantum chromodynamics to order $α_s^2$
The non-divergent diagrams describing two-gluon exchange and annihilation between quarks and antiquarks are calculated in the Feynman gauge, based on quantum chromodynamics in a spherical cavity. Using the experimental $N$, $Δ$, $Ω$, and $ρ$ masses to fit the free parameters of the M.I.T.\ bag model, the predicted states agree very well with the observed low-lying hadrons. As expected, the two-gluon annihilation graphs lift the degeneracy of the $π$ and $η$, while the $ρ$ and $ω$ remain degenerate. Diagonalizing the $η- η'$ subspace Hamiltonian yields a very good value for the mass of the $η$ meson.
hep-ph↗