Symbol alphabets in QCD and flag cluster algebras
Abstract
A bstract The full 245-letter symbol alphabet for all planar massless two-loop six-point Feynman integrals was recently determined in arXiv:2412.19884 and arXiv:2501.01847. In a parallel mathematical development, it was shown in arXiv:2408.14956 that there is an embedding of the cluster algebra associated to the partial flag variety $$ {\mathcal{Fl}}_{2,n-2;n} $$ Fl 2 , n − 2 ; n , which describes the kinematics of n massless particles, into that of the Grassmannian Gr( n –2, 2 n –4). In this paper we connect these developments by showing that most of the rational symbol letters can be expressed in terms of flag cluster variables, and that all of the algebraic symbol letters arise from infinite mutation sequences.
Fields of Study & Subjects
Particle physics theoretical and experimental studies
Algebraic structures and combinatorial models
Advanced Mathematical Theories and Applications
Publication details
- Journal / source
- Journal of High Energy Physics
- Publisher
- Springer Science and Business Media LLC
- Volume
- 2026
- Issue
- 3
- Publication date
- 12 March 2026
- Language
- EN