General Structure of Conformal Anomaly and 4 Dimensional Photon-Dilaton Gravity

The general structure of the conformal anomaly and the dilaton's effect to it are analysed. First we give a new formal proof of the statement that the conformal anomaly, in the theory which is conformal invariant at the classical level, is conformal invariant. The heat-kernel regularization and Fujikawa's method are taken for the analysis. We present a new explicit result of the conformal anomaly in 4 dimensional photon-dilaton gravity. This result is examined from the point of the general structure.