Abstract
In this paper we focus on scattering amplitudes in maximally supersymmetric Yang-Mills theory and define a long sought-after geometry, the loop momentum amplituhedron, which we conjecture to encode tree and (the integrands of) loop amplitudes in spinor helicity variables. Motivated by the structure of amplitude singularities, we define an extended positive space, which enhances the Grassmannian space featuring at tree level, and a map which associates to each of its points tree-level kinematic variables and loop momenta. The image of this map is the loop momentum amplituhedron. Importantly, our formulation provides a global definition of the loop momenta. We conjecture that for all multiplicities and helicity sectors, there exists a canonical logarithmic differential form defined on this space, and provide its explicit form in a few examples.
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Acknowledgments
We would like to thank A. Lipstein and J. Trnka for useful discussions. This work was partially funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) — Projektnummern 404358295 and 404362017. This research was partially supported by the Munich Institute for Astro-, Particle and BioPhysics (MIAPbP) which is funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany’s Excellence Strategy — EXC-2094 — 390783311.
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Ferro, L., Łukowski, T. The Loop Momentum Amplituhedron. J. High Energ. Phys. 2023, 183 (2023). https://doi.org/10.1007/JHEP05(2023)183
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DOI: https://doi.org/10.1007/JHEP05(2023)183