2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/176551We develop a unitarity method to compute one-loop amplitudes with massless propagators in d=4-2*epsilon dimensions. We compute double cuts of the loop amplitudes via a decomposition into a four-dimensional and a -2*epsilon-dimensional integration. The four-dimensional integration is performed using spinor integration or other efficient techniques. The remaining integral in -2*epsilon dimensions is cast in terms of bubble, triangle, box, and pentagon master integrals using dimensional shift identities. The method yields results valid for arbitrary values of epsilon.4 pages. v2: references changedHigh Energy Physics - PhenomenologyHigh Energy Physics - Theorytext