Non-Abelian and type-A conformal anomalies from Euler descent

We classify the non-Abelian anomaly of the Euclidean conformal group SO(2n + 1, 1) in 2n dimensions via Stora-Zumino descent from its Euler invariant polynomial in 2n + 2 dimensions. In this way, we place the conformal anomaly on the same footing as ordinary perturbative ’t Hooft anomalies. We also explore the relation of the non-Abelian anomaly to the known type-A Weyl anomaly, which involves projecting into a Weyl cocycle. We discuss implications for anomaly inflow, and ’t Hooft anomaly matching for the full conformal group with a Wess-Zumino-Witten term. In 4d, this enables the construction of a dilaton effective action matching the full non-Abelian SO(5, 1) conformal anomaly.