Chinese Magic in Loop Integrals

Abstract

We present an approach to higher point loop integrals using Chinese magic in the virtual loop integration variable. We show, using the five point function in the important e^+e^-\to f\bar{f}+\gamma process for ISR as a pedagogical vehicle, that we get an expression for it directly reduced to one scalar 5-point function and 4-, 3-, and 2- point integrals, thereby avoiding the computation of the usual three tensor 5-pt Passarino-Veltman reduction. We argue that this offers potential for greater numerical stability.

Comments: 11 pages, 1 figure; improved figure, improved text and references;added CERN report number;extended text; corrected misprint; extended text, improved figure; improved text, fonts and style; extended text for publication in Phys. Rev. D (title changed in journal)