Computing One-Loop Amplitudes From The Holomorphic Anomaly Of Unitarity Cuts

Abstract

We propose a systematic way to carry out the method introduced in hep-th/0410077 for computing certain unitarity cuts of one-loop N=4 amplitudes of gluons. We observe that the class of cuts for which the method works involves all next-to-MHV n-gluon one-loop amplitudes of any helicity configurations. As an application of our systematic procedure, we obtain the complete seven-gluon one-loop leading-color amplitude A_{7;1}(1-,2-,3-,4+,5+,6+,7+).

30 pages, harvmac, 2 figures. v2: Minor corrections, typos fixed, Appendix B added. v3: Note added at end of introduction, paragraph added in section 2