RENORMALIZATION-GROUP PROPERTIES OF HIGHER-DERIVATIVE QUANTUM-GRAVITYWITH MATTER IN 4-EPSILON DIMENSIONS

We investigate the phase structure and the infrared properties of high er-derivative quantum gravity (QG) with matter, in 4 - epsilon dimensi ons, The renormalization group (RG) equations in 4 - epsilon dimension s are analysed for the following types of matter: the f phi(4) theory, the O(N)phi(4) theory, scalar electrodynamics, and the SU(2) model wi th scalars. New fixed points for the scalar coupling appear-one of whi ch is IR stable-some of them being induced by QG. The IR stable fixed point perturbed by QG leads to a second-order phase transition for the theory at non-zero temperature. The RG improved effective potential i n the SU(2) theory (which can be considered as the confining phase of the standard model) is calculated at non-zero temperature and it is sh own that its shape is clearly influenced by QG.