Color-flow decomposition of QCD amplitudes

By Fabio Maltoni, Kevin Paul, Tim Stelzer, S. Willenbrock. 2002

148 citations recorded by the source corpus.

We introduce a new color decomposition for multi-parton amplitudes in QCD, free of fundamental-representation matrices and structure constants. This decomposition has a physical interpretation in terms of the flow of color, which makes it ideal for merging with shower Monte-Carlo programs. The color-flow decomposition allows for very efficient evaluation of amplitudes with many quarks and gluons, many times faster than the standard color decomposition based on fundamental-representation matrices. This will increase the speed of event generators for multi-jet processes, which are the principal backgrounds to signals of new physics at colliders.

Subfields: Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/6de22453ea36b94217367c64e28ab8cdfbd53704

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In Nuclear and High Energy Physics

Citations in the corpus

QCD matrix elements and truncated showers (2009, background): “It was pointed out in [36, 37] that the colour-flow decomposition of QCD amplitudes is advantageous over both the fundamental and (if existent) the adjoint representation decomposition.”
Electroweak radiative corrections for collider physics (2019, result): “Employing colour decompositions [349], the colour matrix appearing in the squared amplitude is computed automatically once and for all and then stored in memory, similarly as in OpenLoops.”
Recursive generation of one-loop amplitudes in the Standard Model (2012, methodology): “[80, 81] for perturbative QCD computations, where the conventional 8 gluon fields Aμ are replaced by a 3× 3 matrix (Aμ)j = 1 2 A a μ(λ )j with the trace condition ∑ i (Aμ)i = 0.”
Automated event generation for loop-induced processes (2015, methodology): “The solution consists then in projecting the colour factors λl onto a colour-flow basis [31] built out of K colour-flow basis vectors κi (chains of Kronecker delta structures with indices in the (anti-)fundamental representation of SU(3)c).”
Comix, a new matrix element generator (2008, background): “[22] for the fundamental representation decomposition, the adjoint representation decomposition and the colour flow 2 Note that in this context weights have to be normalised to unity on the flight.”
The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations (2014, methodology): “Then, by employing colour decompositions [114–116], they can be organised into gauge-invariant subsets (often called dual amplitudes), each corresponding to an element of a colour basis.”