On the geometry of the orthogonal momentum amplituhedron

Autor: Lukowski, Tomasz, Moerman, Robert, Stalknecht, Jonah
Rok vydání: 2021
Předmět:
Druh dokumentu: Working Paper
DOI: 10.1007/JHEP12(2022)006
Popis: In this paper we study the orthogonal momentum amplituhedron $\mathcal{O}_k$, a recently introduced positive geometry that encodes the tree-level scattering amplitudes in ABJM theory. We generate the full boundary stratification of $\mathcal{O}_k$ and show that its boundaries can be labelled by so-called orthogonal Grassmannian forests (OG forests). We also determine the generating function for enumerating boundaries according to their dimension and show that the Euler characteristic of $\mathcal{O}_k$ equals one. This provides a strong indication that the orthogonal momentum amplituhedron is homeomorphic to a ball. This paper is supplemented with the Mathematica package "orthitroids" which contains useful functions for studying the positive orthogonal Grassmannian and the orthogonal momentum amplituhedron.
Comment: 19 pages, 7 figures
Databáze: arXiv