A Two-Loop Four-Gluon Helicity Amplitude in QCD

Abstract

We present the two-loop pure gauge contribution to the gluon-gluon scattering amplitude with maximal helicity violation. Our construction of the amplitude does not rely directly on Feynman diagrams, but instead uses its analytic properties in 4 - 2 epsilon dimensions. We evaluate the loop integrals appearing in the amplitude through O(epsilon^0) in terms of polylogarithms.

Comments: Latex, 27 pages, 12 figures; v2: normalizations corrected in (5.11), (A.6) and (A.7)