Dual Identities inside the Gluon and the Graviton Scattering Amplitudes
S. -H. Henry Tye, Yang Zhang
TL;DR
This paper uses heterotic and open-string formalisms to refine and prove BCJ-like color–kinematic dualities in M-gluon tree amplitudes, showing how left-moving color factors and right-moving kinematic numerators obey dual Jacobi identities and can be combined via KLT to reproduce YM and gravity amplitudes. It develops a systematic contour-integral approach to generate color and kinematic identities for general M, analyzes gauge-choice issues for the kinematic sector, and demonstrates, through explicit 4- and 5-point examples, that gravity amplitudes can be written diagonally as sums of products of kinematic numerators. The work provides a robust bridge from gauge theory to gravity via string-theoretic constructions and suggests the broader applicability of BCJ dualities to loops and fermionic states. Overall, the study reinforces the deep intertwining of gauge and gravity amplitudes and offers practical pathways to compute them without explicit Feynman rules.
Abstract
Recently, Bern, Carrasco and Johansson conjectured dual identities inside the gluon tree scattering amplitudes. In this paper, we use the properties of the heterotic string and open string tree scattering amplitudes to refine and derive these dual identities. These identities can be carried over to loop amplitudes using the unitarity method. Furthermore, given the $M$-gluon (as well as gluon-gluino) tree amplitudes, $M$-graviton (as well as graviton-gravitino) tree scattering amplitudes can be written down immediately, avoiding the derivation of Feynman rules and the evaluation of Feynman diagrams for graviton scattering amplitudes.
