2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/47856The O(N_f alpha^2) electroweak radiative corrections to the Thomson scattering matrix element are calculated for a general renormalization scheme with massless fermions. All integrals can be evaluated exactly in dimensional regularization which in several cases yields new results that are remarkably simple in form. A number of stringent internal consistency checks are performed. The Z-gamma mixing complicates the calculation of 1-particle reducible diagrams considerably at this order and a general treatment of this problem is given. Conditions satisfied by O(N_f alpha^2) counterterms are derived and may be applied to other calculations at this order.29 pages LaTeX. 6 figures. Uses amsmath.sty, cite.sty and epsfig.styHigh Energy Physics - Phenomenologytext