https://doi.org/10.1140/epjc/s10052-022-11078-2
Special Article - Tools for Experiment and Theory
Improving colour computations in MadGraph5_aMC@NLO and exploring a 
expansion
1
Department of Astronomy and Theoretical Physics, Lund University, Sölvegatan 14A, 223 62, Lund, Sweden
2
Centre for Cosmology, Particle Physics and Phenomenology (CP3), Université catholique de Louvain, Chemin du Cyclotron 2, 1348, Louvain-la-Neuve, Belgium
Received:
19
October
2022
Accepted:
24
November
2022
Published online:
19
December
2022
In this paper, we present an extension of MadGraph5_aMC@NLO which is able to evaluate tree-level QCD matrix-elements up to 
(one more particle than before). To achieve this, we implemented Berends–Giele-like recursion, and re-implemented the way colour is computed such that we can now expand the colour matrix in powers of and truncate this expansion to a chosen order. For high multiplicity samples, even without truncating the colour matrix, the new implementation offers a speed gain compared to the previous MadGraph5_aMC@NLO code.
© The Author(s) 2022
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