Feynman rules for the rational part of the QCD 1-loop amplitudes

Draggiotis, Petros; Garzelli, Maria Vittoria; Papadopoulos, Costas G.; Pittau, R.

doi:10.1088/1126-6708/2009/04/072

Cited by 140 publications

(154 citation statements)

References 48 publications

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“…These tools require not only the input of the tree-level vertices of the model, but in addition the user has to provide all the one-loop ultra-violet counterterms required to renormalize the one-loop amplitude. Furthermore, depending on the underlying algorithm to construct the one-loop matrix element, additional tree-level-like vertices need to be included to reproduce the correct rational terms in the one-loop amplitude [66][67][68][69]. While all of these new vertices formally go beyond a simple tree-level computation from a Lagrangian, they are nevertheless universal (for a given model) and can be computed once and for all.…”

Section: Discussionmentioning

confidence: 99%

FeynRules 2.0 — A complete toolbox for tree-level phenomenology

Alloul

Christensen

Degrande

et al. 2014

Computer Physics Communications

2,366

1,904

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FeynRules is a Mathematica-based package which addresses the implementation of particle physics models, which are given in the form of a list of fields, parameters and a Lagrangian, into high-energy physics tools. It calculates the underlying Feynman rules and outputs them to a form appropriate for various programs such as CalcHep, FeynArts, MadGraph, Sherpa and Whizard. Since the original version, many new features have been added: support for two-component fermions, spin-3/2 and spin-2 fields, superspace notation and calculations, automatic mass diagonalization, completely general FeynArts output, a new universal FeynRules output interface, a new Whizard interface, automatic 1 → 2 decay width calculation, improved speed and efficiency, new guidelines for validation and a new web-based validation package. With this feature set, FeynRules enables models to go from theory to simulation and comparison with experiment quickly, efficiently and accurately.

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Section: Discussionmentioning

confidence: 99%

FeynRules 2.0 — A complete toolbox for tree-level phenomenology

Alloul

Christensen

Degrande

et al. 2014

Computer Physics Communications

2,366

1,904

View full text Add to dashboard Cite

show abstract

“…In particular, one can show [158] that the computation of R 2 is equivalent to that of a tree-level amplitude, constructed with a universal set of theory-dependent rules (see ref. [159], refs. [160][161][162], and refs.…”

Section: Jhep07(2014)079mentioning

confidence: 99%

The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations

Alwall

Frederix

Frixione

et al. 2014

J. High Energ. Phys.

6,069

5,572

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We discuss the theoretical bases that underpin the automation of the computations of tree-level and next-to-leading order cross sections, of their matching to parton shower simulations, and of the merging of matched samples that differ by light-parton multiplicities. We present a computer program, MadGraph5 aMC@NLO, capable of handling all these computations -parton-level fixed order, shower-matched, merged -in a unified framework whose defining features are flexibility, high level of parallelisation, and human intervention limited to input physics quantities. We demonstrate the potential of the program by presenting selected phenomenological applications relevant to the LHC and to a 1-TeV e + e − collider. While next-to-leading order results are restricted to QCD corrections to SM processes in the first public version, we show that from the user viewpoint no changes have to be expected in the case of corrections due to any given renormalisable Lagrangian, and that the implementation of these are well under way.

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“…[76,77,78]. Finally we note that yet another unitarity-based method for the calculation of the rational part has been developed [79,80].…”

Section: Comments On the Rational Partmentioning

confidence: 98%

One-loop calculations in quantum field theory: From Feynman diagrams to unitarity cuts

et al. 2012

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The success of the experimental program at the Tevatron re-inforced the idea that precision physics at hadron colliders is desirable and, indeed, possible. The Tevatron data strongly suggests that one-loop computations in QCD describe hard scattering well. Extrapolating this observation to the LHC, we conclude that knowledge of many short-distance processes at next-to-leading order may be required to describe the physics of hard scattering. While the field of oneloop computations is quite mature, parton multiplicities in hard LHC events are so high that traditional computational techniques become inefficient. Recently new approaches based on unitarity have been developed for calculating one-loop scattering amplitudes in quantum field theory. These methods are especially suitable for the description of multi-particle processes in QCD and are amenable to numerical implementations. We present a systematic pedagogical description of both conceptual and technical aspects of the new methods.

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Feynman rules for the rational part of the QCD 1-loop amplitudes

Cited by 140 publications

References 48 publications

FeynRules 2.0 — A complete toolbox for tree-level phenomenology

FeynRules 2.0 — A complete toolbox for tree-level phenomenology

The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations

One-loop calculations in quantum field theory: From Feynman diagrams to unitarity cuts

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