Spin gravity: a non-Abelian gauge theory on a flat spacetime

In this paper, I show that a Yang-Mills force with a U(1)$\timesSU(2)\times$SU(2) group symmetry predicts solar system observations of gravitational behavior as well as binary pulsar precession provided that mass is redefined as intrinsic static pressure and all stress-energy-momentum tensors are, thus, traceless. Using a homogeneous, isotropic universe model, I show that this theory explains the accelerating expansion of the universe directly from group symmetry with no ad hoc constants and predicts that antimatter and matter gravitationally repel one another (antimatter "falls" up). In addition, because it is a generic massless Yang-Mills theory, it is a renormalizable quantum theory.