Locality and Unitarity of Scattering Amplitudes from Singularities and Gauge Invariance.

@article{ArkaniHamed2018LocalityAU,
  title={Locality and Unitarity of Scattering Amplitudes from Singularities and Gauge Invariance.},
  author={Nima Arkani-Hamed and Laurentiu Rodina and Jaroslav Trnka},
  journal={Physical review letters},
  year={2018},
  volume={120 23},
  pages={
          231602
        }
}
We conjecture that the leading two-derivative tree-level amplitudes for gluons and gravitons can be derived from gauge invariance together with mild assumptions on their singularity structure. Assuming locality (that the singularities are associated with the poles of cubic graphs), we prove that gauge invariance in just n-1 particles together with minimal power counting uniquely fixes the amplitude. Unitarity in the form of factorization then follows from locality and gauge invariance. We also… 
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References

SHOWING 1-10 OF 30 REFERENCES
On tree amplitudes in gauge theory and gravity
The BCFW recursion relations provide a powerful way to compute tree amplitudes in gauge theories and gravity, but only hold if some amplitudes vanish when two of the momenta are taken to infinity in
Effective Field Theories from Soft Limits of Scattering Amplitudes.
TLDR
This work proposes a natural classification of all scalar effective field theories according to two numbers which encode the derivative power counting and soft behavior of the corresponding amplitudes, in those cases where there is no consistent amplitude.
Constraining subleading soft gluon and graviton theorems
We show that the form of the recently proposed subleading soft graviton and gluon theorems in any dimension are severely constrained by elementary arguments based on Poincar\'e and gauge invariance
Scattering equations and matrices: from Einstein to Yang-Mills, DBI and NLSM
A bstractThe tree-level S-matrix of Einstein’s theory is known to have a representation as an integral over the moduli space of punctured spheres localized to the solutions of the scattering
Scattering of massless particles in arbitrary dimensions.
TLDR
A compact formula for the complete tree-level S-matrix of pure Yang-Mills and gravity theories in arbitrary spacetime dimensions is presented and Gauge invariance is completely manifest as it follows from a simple property of the Pfaffian.
New Relations for Gauge-Theory Amplitudes
We present an identity satisfied by the kinematic factors of diagrams describing the tree amplitudes of massless gauge theories. This identity is a kinematic analog of the Jacobi identity for color
A periodic table of effective field theories
A bstractWe systematically explore the space of scalar effective field theories (EFTs) consistent with a Lorentz invariant and local S-matrix. To do so we define an EFT classification based on four
Higher-spin massless $S$-matrices in four-dimensions
On-shell, analytic $S$-matrix elements in massless theories are constructed from a finite set of primitive three-point amplitudes, which are fixed by Poincar\'e invariance up to an overall numerical
Graviton and Gluon Scattering from First Principles.
TLDR
By systematic analysis exceptional graviton scattering amplitudes are derived, which in general dimensions cannot be related to gluon amplitudes.
The Amplituhedron
A bstractPerturbative scattering amplitudes in gauge theories have remarkable simplicity and hidden infinite dimensional symmetries that are completely obscured in the conventional formulation of
...
...