TY - JOUR
T1 - New Representations of the Perturbative S Matrix
AU - Baadsgaard, Christian
AU - Bjerrum-Bohr, N. E.J.
AU - Bourjaily, Jacob L.
AU - Caron-Huot, Simon
AU - Damgaard, Poul H.
AU - Feng, Bo
N1 - Publisher Copyright:
© 2016 American Physical Society.
PY - 2016/2/10
Y1 - 2016/2/10
N2 - 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 nonplanar theories without well-defined forward limits or good ultraviolet behavior.
AB - 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 nonplanar theories without well-defined forward limits or good ultraviolet behavior.
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U2 - 10.1103/PhysRevLett.116.061601
DO - 10.1103/PhysRevLett.116.061601
M3 - Article
AN - SCOPUS:84957989763
SN - 0031-9007
VL - 116
JO - Physical review letters
JF - Physical review letters
IS - 6
M1 - 061601
ER -