Recursion Relations, Generating Functions, and Unitarity Sums in N=4 SYM
Theory
release_vyuaw3lsgrernfzhizkatowsra
by
Henriette Elvang, Daniel Z. Freedman, Michael Kiermaier
(2008)
Abstract
We prove that the MHV vertex expansion is valid for any NMHV tree amplitude
of N=4 SYM. The proof uses induction to show that there always exists a complex
deformation of three external momenta such that the amplitude falls off at
least as fast as 1/z for large z. This validates the generating function for
npoint NMHV tree amplitudes. We also develop generating functions for antiMHV
and antiNMHV amplitudes. As an application, we use these generating functions
to evaluate several examples of intermediate state sums on unitarity cuts of
1, 2, 3 and 4loop amplitudes. In a separate analysis, we extend the recent
results of arXiv:0808.0504 to prove that there exists a valid 2line shift for
any npoint tree amplitude of N=4 SYM. This implies that there is a BCFW
recursion relation for any tree amplitude of the theory.
In text/plain
format
Archived Files and Locations
application/pdf 557.6 kB
file_gtpyd3mce5dw5fskx3egpflw4u

archive.org (archive) 
article
Stage
accepted
Date 20081220
Version
v2
Language
en
^{?}
0808.1720v2
access all versions, variants, and formats of this works (eg, preprints)