2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/149019We present a simple derivation of the one-loop trace anomaly in spinor QED through dispersion relations, avoiding completely any ultraviolet regularization. The anomaly can be expressed as a convergent sum rule for the imaginary part of a relevant formfactor. In the massless limit, the imaginary part produces a delta-function singularity at zero external momentum squared. Such a treatment reveals an "infrared face" of the trace anomaly, in striking similarity with the well-known case of the axial anomaly.12 pages LATEX, minor changes in referencesHigh Energy Physics - PhenomenologyHigh Energy Physics - Theorytext