  A modified gravitational theory is developed in which the gravitational
coupling constants $G$ and $Q$ and the effective mass $m_\phi$ of a repulsive
vector field run with momentum scale $k$ or length scale $\ell =1/k$, according
to a renormalization group flow. The theory can explain cosmological early
universe data with a dark hidden photon and late time galaxy and cluster
dynamics without dark matter. The theory agrees with solar system and binary
pulsar observations.
