  In Article I, a harmonic-oscillator model of a universe of n quarks is
infinitesimally modified to eliminate the background reference frame. As a
result, quark trajectories exhibit the unification of gravity and the harmonic
oscillator near the horizon of a quantum black hole, a region that is
approximately flat in space-time. Constituent quarks are confined to composite
particles by cluster decomposition rather than a binding force. Here, the
composite-particles are input for a perturbation model of particle-exchange
interactions. As in Article I, the Hamiltonian cannot be expressed as H=H0+HI
where H0 generates the unperturbed equations of motion. In the present article,
H0 annihilates the initial state. Quark substructures yield exchange particles
of various masses and angular momenta and thus a natural unification of forces.
The background-frame elimination in the fundamental model implies causality and
unitarity in the effective model. Feynman propagators are derived and
first-order scattering amplitudes are calculated for elastic and inelastic
scattering.
