New Representations of the Perturbative S-Matrix
Abstract
We propose a new framework to represent the perturbative S-matrix which is well-defined for all quantum field theories of massless particles, constructed from tree-level amplitudes and integrable term-by-term. This representation is derived from the Feynman expansion through a series of partial fraction identities, discarding terms that vanish upon integration. Loop integrands are expressed in terms of "Q-cuts" that involve both off-shell and on-shell loop-momenta, defined with a precise contour prescription that can be evaluated by ordinary methods. This framework implies recent results found in the scattering equation formalism at one-loop, and it has a natural extension to all orders---even non-planar theories without well-defined forward limits or good ultraviolet behavior.
Keywords
Cite
@article{arxiv.1509.02169,
title = {New Representations of the Perturbative S-Matrix},
author = {Christian Baadsgaard and N. E. J. Bjerrum-Bohr and Jacob L. Bourjaily and Simon Caron-Huot and Poul H. Damgaard and Bo Feng},
journal= {arXiv preprint arXiv:1509.02169},
year = {2016}
}
Comments
4+1 pages, 4 figures