  In 3+1 space-time dimensions, fourth order derivative gravity is
perturbatively renormalizable. Here it is shown that it describes a unitary
theory of gravitons (with/without an additional scalar) in a limited coupling
parameter space which includes standard cosmology. The running of gravitational
constant which includes contribution of graviton is computed. It is shown that
generically Newton's constant vanishes at short distance in this perturbatively
renormalizable and unitary theory.

High Energy Physics - Theory;General Relativity and Quantum Cosmology