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arxiv: 2601.18892 · v3 · submitted 2026-01-26 · ✦ hep-th · hep-ph

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Non-Abelian and Type-A Conformal Anomalies from Euler Descent

Authors on Pith no claims yet

Pith reviewed 2026-05-16 10:29 UTC · model grok-4.3

classification ✦ hep-th hep-ph
keywords anomalyconformalnon-abeliananomaliesdescentdimensionseulerfull
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0 comments X

The pith

Non-Abelian anomalies of the Euclidean conformal group descend from the Euler polynomial in two dimensions higher.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper establishes that the non-Abelian anomaly of the conformal group SO(2n+1,1) in 2n dimensions arises directly through Stora-Zumino descent applied to the Euler invariant polynomial in 2n+2 dimensions. This construction treats the conformal anomaly on the same footing as ordinary perturbative 't Hooft anomalies in gauge theories. A reader would care because the method supplies a systematic origin for the anomaly cocycle and enables explicit matching conditions for the full conformal symmetry, including via a Wess-Zumino-Witten term. In four dimensions the same descent produces a dilaton effective action that reproduces the complete SO(5,1) anomaly.

Core claim

The authors 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. This places the conformal anomaly on the same footing as ordinary perturbative 't Hooft anomalies. They also explore the relation of the non-Abelian anomaly to the known type-A Weyl anomaly, which involves projecting into a Weyl cocycle, and 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.

What carries the argument

Stora-Zumino descent applied to the Euler invariant polynomial, generating the anomaly cocycle for the full non-Abelian conformal group.

If this is right

  • The conformal anomaly can be matched under 't Hooft anomaly matching conditions using a Wess-Zumino-Witten term for the full conformal group.
  • Anomaly inflow from a higher-dimensional topological term reproduces the non-Abelian conformal anomaly.
  • In four dimensions the descended cocycle supplies an explicit dilaton effective action that matches the complete SO(5,1) anomaly.
  • The non-Abelian anomaly is related to the type-A Weyl anomaly by projection onto the appropriate Weyl cocycle.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • The same descent procedure could be used to construct consistent effective actions when conformal symmetry is spontaneously broken in higher even dimensions.
  • It suggests that anomaly inflow provides a geometric origin for conformal anomalies that may appear in holographic duals without additional assumptions.
  • Explicit matching of the full non-Abelian anomaly may constrain possible ultraviolet completions that preserve the entire conformal group.
  • The method offers a route to compute anomaly coefficients in dimensions beyond four without relying on perturbative expansions.
  • keywords:[
  • conformal anomaly
  • non-Abelian anomaly
  • Stora-Zumino descent

Load-bearing premise

The Euler polynomial in 2n+2 dimensions descends to a non-trivial cocycle for the full non-Abelian conformal group without additional obstructions or vanishing conditions specific to the conformal case.

What would settle it

A direct calculation of the conformal anomaly in four dimensions that yields coefficients different from those obtained by descending the six-dimensional Euler polynomial and projecting to the Weyl cocycle.

read the original abstract

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 \textit{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.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

1 major / 1 minor

Summary. The manuscript claims to classify the non-Abelian anomaly of the Euclidean conformal group SO(2n+1,1) in 2n dimensions by applying Stora-Zumino descent to the Euler invariant polynomial in 2n+2 dimensions. This places the conformal anomaly on equal footing with ordinary 't Hooft anomalies. The work further relates the resulting cocycle to the type-A Weyl anomaly via projection onto a Weyl factor, discusses implications for anomaly inflow and 't Hooft matching with a WZW term, and constructs a dilaton effective action in 4d that matches the full non-Abelian SO(5,1) anomaly.

Significance. If the descent produces a non-trivial cocycle for the full non-Abelian group, the result would provide a systematic, descent-based classification of conformal anomalies analogous to gauge anomalies, enabling consistent anomaly matching and effective actions. The explicit 4d dilaton construction offers a concrete, testable application for conformal field theory studies.

major comments (1)
  1. [Stora-Zumino descent and projection onto Weyl cocycle] The central claim that Stora-Zumino descent from the Euler polynomial yields a non-vanishing (2n-1)-cocycle for the full non-Abelian SO(2n+1,1) action rests on the assumption of no conformal-specific obstructions. The abstract notes that the type-A anomaly arises only after projecting the cocycle onto a Weyl factor; this projection step indicates that unprojected components may vanish due to non-compactness, the metric representation, or Euclidean signature. Explicit cocycle expressions or a verification that the descent remains non-trivial without projection are required to support the classification.
minor comments (1)
  1. [Abstract] The abstract refers to results 'in 4d' without stating the range of n for which the general classification holds; adding this clarification would improve readability.

Simulated Author's Rebuttal

1 responses · 0 unresolved

We thank the referee for their careful reading of the manuscript and for identifying the need to strengthen the evidence for the non-vanishing of the full non-Abelian cocycle. We address the major comment below and will incorporate clarifications and explicit expressions in a revised version.

read point-by-point responses
  1. Referee: The central claim that Stora-Zumino descent from the Euler polynomial yields a non-vanishing (2n-1)-cocycle for the full non-Abelian SO(2n+1,1) action rests on the assumption of no conformal-specific obstructions. The abstract notes that the type-A anomaly arises only after projecting the cocycle onto a Weyl factor; this projection step indicates that unprojected components may vanish due to non-compactness, the metric representation, or Euclidean signature. Explicit cocycle expressions or a verification that the descent remains non-trivial without projection are required to support the classification.

    Authors: The Stora-Zumino descent is performed on the Euler invariant polynomial in the standard manner, yielding a non-trivial (2n-1)-cocycle for the full conformal group action; the non-vanishing follows directly from the topological properties of the Euler class and the absence of additional obstructions in the descent equations for this case. The projection onto a Weyl factor is introduced only to isolate the type-A component and relate it to the known Weyl anomaly, but the unprojected cocycle remains non-zero for general conformal transformations. To address the request for explicit verification, we will include the explicit form of the (2n-1)-cocycle in the revised manuscript together with a direct check that it satisfies the descent equations without vanishing prior to projection. revision: yes

Circularity Check

0 steps flagged

Standard Stora-Zumino descent from independently known Euler polynomial; derivation self-contained

full rationale

The paper's central construction starts from the known Euler invariant polynomial in 2n+2 dimensions and applies the standard Stora-Zumino descent procedure to obtain the non-Abelian anomaly cocycle for SO(2n+1,1). No equations or steps in the provided abstract or description reduce the result to a self-definition, a fitted parameter renamed as prediction, or a load-bearing self-citation chain. The type-A projection is presented as an additional step after descent, not as a redefinition of the input. The derivation is therefore independent of its own outputs and receives the default non-circularity finding.

Axiom & Free-Parameter Ledger

0 free parameters · 2 axioms · 0 invented entities

The construction rests on the standard mathematical properties of the Euler class and the Stora-Zumino descent procedure, which are taken from prior literature without new free parameters or invented entities.

axioms (2)
  • standard math The Euler polynomial in 2n+2 dimensions is a closed invariant that descends to a non-trivial cocycle for the conformal group in 2n dimensions.
    Invoked in the classification step; this is a standard fact from characteristic class theory.
  • domain assumption Projection onto the Weyl cocycle recovers the known type-A anomaly without loss of information about the non-Abelian structure.
    Stated in the abstract as the relation explored between non-Abelian and type-A anomalies.

pith-pipeline@v0.9.0 · 5444 in / 1449 out tokens · 29205 ms · 2026-05-16T10:29:30.856225+00:00 · methodology

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