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arXiv · 1905.04216

The Momentum Amplituhedron

David Damgaard·Livia Ferro·Tomasz Lukowski·Matteo Parisi
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Abstract

In this paper we define a new object, the momentum amplituhedron, which is the long sought-after positive geometry for tree-level scattering amplitudes in $\mathcal{N}=4$ super Yang-Mills theory in spinor helicity space. Inspired by the construction of the ordinary amplituhedron, we introduce bosonized spinor helicity variables to represent our external kinematical data, and restrict them to a particular positive region. The momentum amplituhedron $\mathcal{M}_{n,k}$ is then the image of the positive Grassmannian via a map determined by such kinematics. The scattering amplitudes are extracted from the canonical form with logarithmic singularities on the boundaries of this geometry.

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David Damgaard, Livia Ferro, Tomasz Lukowski, Matteo Parisi. 2019-05-10. The Momentum Amplituhedron. https://doi.org/10.1007/jhep08(2019)042

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