Conformal anomalies in 6D four-derivative theories: A heat-kernel analysis

We compute the conformal anomalies for some higher-derivative (nonunitary) 6D Weyl invariant theories using the heat-kernel expansion in the background-field method. To this aim we obtain the general expression for the Seeley-DeWitt coefficient b6 for 4-derivative differential operators with background curved geometry and gauge fields, which was known only in flat space so far. We consider 4-derivative scalars and Abelian vectors as well as 3-derivative fermions, confirming the result of the literature obtained via indirect methods. We generalize the vector case by including the curvature coupling FFWeyl