The decay of 2-gluon colour singlets in quarks: 2g\rightarrow q\bar q +2q2\bar q has been simulated with the Monte-Carlo method, taking into account an effective 1-gluon exchange interaction between the emitted quarks, which was folded with a 2-gluon density determined self-consistently. 2-gluon densities were found with different radii, which correspond to 0⁺⁺ glueballs of the size of light q\bar q, s\bar s, c\bar c, b\bar b and heavier q\bar q systems. Binding potentials between the two gluons have been deduced, which are consistent with the confinement potential from lattice results. However, self-consistency for the deduction of 2-gluon densities requires  massless (or very light) quarks for all flavours. The masses are given by the binding energies of quarks and gluons, yielding excitation spectra of 0⁺⁺ glueballs and  \Phi , J/\Psi  and  \Upsilon  states consistent with observation. The sum of q--q potentials yields a strong coupling \alpha _s consistent with the available data up to large momenta. The nucleon is described by a gluonium state coupled to 3 valence quarks, yielding ground state and radial excitations consistent with experiment. Finally, we discuss the compressibility of the nucleon and relate it to that of nuclear matter.

PACS numbers: 12.38.Aw, 12.39.Mk, 14.20.Dh, 14.40.--n