All-gluon amplitudes with off-shell recursion in multiplet bases

Summary, in English

The efficient computation of color-summed QCD amplitudes at high parton multiplicities remains a central challenge for precision collider predictions. Existing approaches using trace, color-flow, or adjoint bases suffer from non-orthogonality, which complicates the color algebra and scales poorly with multiplicity. In this work, we present an off-shell recursive framework for computing all-gluon tree-level amplitudes directly in orthogonal multiplet bases. Utilizing Wigner 6j coefficients, we construct an algorithm that builds multiplet-projected off-shell currents from lower-point currents. By optimizing the recursion through partial summation and caching, we find that the computational complexity of calculating n-gluon color-summed squared amplitudes scales as O17n. This demonstrates the potential competitiveness of multiplet bases for high-multiplicity processes.

• Author: Oskar Bolinder; Rikkert Frederix; Malin Sjodahl
• Department/s: Department of Physics
• Publishing year: 2025-10
• Language: English
• Publication/Series: Journal of High Energy Physics
• Volume: 2025
• Issue: 10
• Links: http://dx.doi.org/10.1007/JHEP10(2025)168
• Document type: Journal article
• Publisher: Springer
• Topic: Subatomic Physics
• Keywords: Automation; Parton Shower; Specific QCD Phenomenology
• Status: Published
• ISBN/ISSN/Other: ISSN: 1029-8479