Gauge anomalies (and cancellations)

[diegzumillo]

Hey all
As usual I can get through the specifics of calculations on books but the big picture escapes me. I'm having difficulty understanding gauge anomalies and cancellations. To be more specific, every book I read talks about Feynman diagrams, giving the impression that gauge anomalies are a perturbative phenomena. On the other hand, the anomaly seems to come from a symmetry of the lagrangian on chiral theories, and I don't see anything perturbation-specific there.

I'd appreciate any help, indlucing some interesting references on the subject.

 

[DrDu]

The point is that an "anomalous" symmetry is a symmetry which is a symmetry of the classical model but not of the quantum model. So nonperturbatively, you won't see any symmetry at all.

 

[diegzumillo]

Just to be clear. When you say classical model and quantum you are referring to the Lagrangian symmetries and the usual quantization procedures, or equivalently tree-level and higher order diagrams, right? And in a hypothetical scenario, if we could study this system in, say, a lattice there would be no symmetry to be broken in the first place.