Automation of next-to-leading order computations in QCD: the FKS subtraction

By R. Frederix, Stefano Frixione, Fabio Maltoni, Tim Stelzer. 2009

317 citations recorded by the source corpus.

We present the complete automation of the universal subtraction formalism proposed by Frixione, Kunszt, and Signer for the computation of any cross section at the next-to-leading order in QCD. Given a process, the only ingredient to be provided externally is the infrared- and ultraviolet-finite contribution of virtual origin. Our implementation, currently restricted to the case of e+e− collisions, is built upon and works in the same way as MadGraph. It is particularly suited to parallel computation, and it can deal with any physical process resulting from a theory implemented in MadGraph, thus including the Standard Model as well as Beyond the Standard Model theories. We give results for some sample processes that document the performances of the implementation, and show in particular how the number of subtraction terms has an extremely mild growth with final-state multiplicity.

Subfields: Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/e4fa194c9fb472c123b0e205787bf92230feef37

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Citations in the corpus

Scalar and pseudoscalar Higgs production in association with a top–antitop pair (2011, methodology): “The other matrix-element contributions to the cross sections, their phasespace subtractions according to the FKS formalism [24], their combinations with the one-loop results, and their integration are performed by MadFKS [25].”
Constraints on the gluon PDF from top quark pair production at hadron colliders (2013, methodology): “To study the impact of the improvement of gluon PDF uncertainties there, we have computed top quark pair production with the aMC@NLO program [85–87], at NLO matched to the Herwig6 shower [88].”
The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations (2014, methodology): “(2.49) is what has been originally implemented inMadFKS.”
Combining higher-order resummation with multiple NLO calculations and parton showers in GENEVA (2012, background): “However, given that the integral of the subtraction counterterms over the whole phase space is known analytically for both massless and massive partons [17, 70, 71],”
MadAnalysis 5, a user-friendly framework for collider phenomenology (2012, background): “On the one hand, the generation of the real emission contributions with the appropriate subtraction terms has been achieved in an automatic way [16, 17, 18, 19, 20, 21].”
Collider physics at the precision frontier (2020, methodology): “Sector-improved residue subtraction [952–955] has been inspired by sector decomposition applied to phase space integrals [956–961, 373, 962, 377] and FKS subtraction [910, 921].”
A framework for Higgs characterisation (2013, methodology): “Finally, we mention that Level-2 studies in tt̄ associated production can be performed for spin-0 [82] and spin-1 [61] in a fully automatic way.”
Electroweak radiative corrections for collider physics (2019, methodology): “28The automation of FKS subtraction [53] has been accomplished as well [328, 380] and represents the underlying IR subtraction method of the MadGraph5 aMC@NLO [68] and POWHEG [398, 399] Monte Carlo programs.”
A general framework for implementing NLO calculations in shower Monte Carlo programs: the POWHEG BOX (2010, background): “[32] have also proposed a general FKS implementation for e+e− processes, and they are currently extending it to hadronic collisions [39].”
Lifting degeneracies in Higgs couplings using single top production in association with a Higgs boson (2012, background): “, thj and tZj, a task that can now be accomplished in a fully automatic way [15, 27, 28, 32].”
N-jettiness subtractions for NNLO QCD calculations (2015, methodology): “1) using FKS subtractions [1–3, 104, 105], the cross section is obtained as follows:”
Les Houches 2015: Physics at TeV Colliders Standard Model Working Group Report (2016, methodology): “The automation of the NLO QCD and EW corrections for a generic SM process has required major improvements for all the building blocks of the MadGraph5_aMC@NLO code [282,305].”
Automation of one-loop QCD computations (2011, background): “[1]; that of the former task is the subject of this paper.”
MadGraph 5: going beyond (2011, methodology): “The resulting tool, MadLoop [32] interfaced to MadFKS [24], allows a fully automatic calculation of infrared-safe observables at NLO in QCD for a wide range of processes in the Standard Model.”
Les Houches 2017: Physics at TeV Colliders Standard Model Working Group Report (2017, methodology): “In particular, virtual contributions are numerically calculated by the MadLoop module [479], which will be described later, while the real emission contributions are regulated using the Frixione-KunsztSigner (FKS) subtraction method [142, 143, 421].”