Stress-tensor conformal anomaly for scalar, spinor, and vector fields

The conformal trace anomalies for massless scalar, "neutrino," and photon fields propagating in an arbitrary Riemannian space-time are derived. They are seen to be a consequence of the subtraction, during renormalization, of a finite term, ~ln(m²L²), which violates the scale invariance of the massless theory. A general derivation of the scalar anomaly is given based on the ζ-function regularization developed earlier.