We present a complete momentum-space prescription for the renormalisation of tensorial correlators in conformal field theories. Our discussion covers all 3-point functions of stress tensors and conserved currents in arbitrary spacetime dimensions. In dimensions three and four, we give explicit results for the renormalised correlators, the anomalous Ward identities they obey, and the conformal anomalies. For the stress tensor 3-point function in four dimensions, we identify the specific evanescent tensorial structure responsible for the type A Euler anomaly, and show this anomaly has the form of a double copy of the chiral anomaly.
A complete momentum-space renormalisation prescription is given for all 3-point functions of stress tensors and conserved currents in arbitrary dimensions, with explicit d=3,4 results, and the type A Euler anomaly in d=4 is shown to arise from a specific evanescent tensor structure and to take the form of a double copy of the chiral anomaly.
That the dimensional/momentum-space regularisation scheme used preserves enough of the conformal and conservation structure for the identified evanescent tensor to unambiguously generate the type A Euler anomaly — scheme dependence of evanescent operators is a well-known subtlety and the 'double copy of chiral anomaly' interpretation rests on this identification, which cannot be checked from the abstract.
1/ In CFT, 3-point functions of stress tensors and currents are fixed up to a few constants, but in momentum space they are UV-divergent and need renormalisation. This paper gives a uniform prescription for doing that, for all such tensorial 3-points in any dimension. 2/ In d=3 and d=4 they write the renormalised correlators explicitly, derive the anomalous Ward identities they satisfy, and read off the conformal anomalies (a- and c-type in 4d, etc.). 3/ The structural payoff: the d=4 type A (Euler) anomaly is traced to an evanescent tensor — a structure that vanishes in exactly 4d but contributes through 1/ε poles — and its form mirrors a 'double copy' of the chiral (ABJ) anomaly.
They show how to clean up infinities in special CFT correlators and find one anomaly is two chiral anomalies multiplied together.
Abstract-only review. The paper is by established authors in momentum-space CFT (Bzowski–McFadden–Skenderis) extending their prior renormalisation programme to tensorial 3-point functions. The claims are concrete and computational: explicit renormalised correlators, anomalous Ward identities, and conformal anomalies in d=3,4. The most striking structural claim — that the type A Euler anomaly arises from an evanescent tensor structure and has the form of a 'double copy' of the chiral anomaly — is plausible given known double-copy/anomaly relations but cannot be verified without the full text. Confidence kept LOW because the technical content (tensor decompositions, evanescent structures, regularisation scheme dependence) is exactly where errors hide and is invisible from the abstract. No red flags from abstract alone; correctness risk rated low given authors' track record and the constructive nature of the claims, but this is a prior, not verification.