2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/204426We give a new interpretation of the Faddeev-Mickelsson anomaly in certain Yang-Mills theories in terms of S^1-central extensions of Lie groupoids.v2. 27 pages, content reorganizedDifferential GeometryMathematical Physics22A22; 81T13Anomalies in gauge theory and gerbes over quotient stackstext