Confining Quantum Chromodynamics Model for 3-Quark Baryons, New Mass Source, `Proton Spin Crisis' Solution and Idealized Quark-Lepton Mass Symmetry

We discuss a model for the relativistic bound states of 3-quark baryons based on confining quantum chromoynamics (QCD) with general Yang-Mills symmetry. The model postulates that 3-quark states are formed by consecutive 2-body collisions. For a proton, d and u quarks get together first, and then they capture another u quark so that the d quark is at the core to form a stable proton state with intergral electric charge. The two u quarks form a quantum spheric shell and move in a confining potential $C(r)= Q' r$ of the core d quark. The confining potential $C(r)$ is a static solution of new `phase' fields satisfying the fourth-order equation based on general Yang-Mills symmetry. The two u quarks with the confining linear potentials $C(r)$ in the spherical shell can produce an effective quark Hooke potential $V_{qH}(r)=Qr^2 + V_o$ for the d quark at the core, where Q and $Q'$ are not independent. The proton mass is assumed to be approximately given by $E(d) + 2E(u)$, which can be obtained analytically from Dirac Hamiltonians involving $V_{qH}(r)$ and $C(r)$ for d and two u quarks respectively. The model gives a reasonable understanding of roughly 120 baryon masses based on two different coupling constants and one free parameter $V_o$ for sub-spectra specfied by $J^P$. These results are roughly within 20\% in percent deviation, which appears to be independent of the assumption of color charges. The confining QCD model also gives the neutron-proton mass difference $\approx 0.6 MeV$. We propose an experimental test of the proton structure.