Merging meets matching in MC@NLO

By R. Frederix, Stefano Frixione. 2012

1,057 citations recorded by the source corpus.

A bstractThe next-to-leading order accuracy for MC@NLO results exclusive in J light jets is achieved if the computation is based on matrix elements that feature J and J + 1 QCD partons. The simultaneous prediction of observables which are exclusive in different light-jet multiplicities cannot simply be obtained by summing the above results over the relevant range in J; rather, a suitable merging procedure must be defined. We address the problem of such a merging, and propose a solution that can be easily incorporated into existing MC@NLO implementations. We use the automated aMC@NLO framework to illustrate how the method works in practice, by considering the production at the 8 TeV LHC of a Standard Model Higgs in association with up to J = 2 jets, and of an e+νe pair or a $ t\overline{t} $ pair in association with up to J = 1 jet.

Subfields: Artificial Intelligence, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/5248d8331ca09bc2de4f0ace0a50eb0bb48f5442

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Citations in the corpus

Merging H/W/Z + 0 and 1 jet at NLO with no merging scale: a path to parton shower + NNLO matching (2012, background): “[10], conservatively, use merging scales which are not too low.”
Les Houches 2015: Physics at TeV Colliders Standard Model Working Group Report (2016, background): “dat, the FxFx merging [379] is turned on.”
Electron and photon reconstruction and identification with the CMS experiment at the CERN LHC (2020, methodology): “The matrix elements are computed at NLO for the three processes pp → Z + Njets, where Njets = 0, 1, 2, and merged with the parton showers using the FxFx [25] scheme with a merging scale of 30 GeV.”
Evidence for Higgs boson decay to a pair of muons (2020, methodology): “For processes simulated at NLO (LO) in QCD with the MadGraph5_amc@nlo generator, events from the ME characterized by different parton multiplicities are merged via the FxFx (MLM) prescription [66, 67].”
Les Houches 2013: Physics at TeV Colliders: Standard Model Working Group Report (2014, methodology): “Jet multiplicities are then merged using the FxFx merging prescription [357].”
Simplified dark matter models with two Higgs doublets: I. Pseudoscalar mediators (2017, methodology): “2 using a FxFx NLO jet matching prescription [107] and the final-state top quarks have been decayed with MadSpin [108].”
Measurement of differential cross sections for top quark pair production using the lepton+jets final state in proton-proton collisions at 13 TeV (2016, methodology): “In another simulation all processes of up to two additional partons are calculated at NLO and combined with the PYTHIA8 parton shower simulation using the FxFx [18] algorithm.”
Event generation with Sherpa 2.2 (2019, methodology): “ements and parton showers is taken, and any overlaps are carefully removed to fully maintain the respective accuracies throughout. Other formulations and approximations thereof have been presented in [134, 135, 136, 137]. NLO EW Corrections in Matching and Merging In [138, 139], an approach to incor”
A framework for Higgs characterisation (2013, methodology): “Among other things, this will also provide one with the possibility of using the FxFx NLO-merging [106] framework, which has the advantages of both the ME+PS and aMC@NLO approaches.”
Performance of missing transverse momentum reconstruction in proton-proton collisions at √s = 13 TeV using the CMS detector (2019, methodology): “For the MADGRAPH5 aMC@NLO samples, jets from the matrix element calculations are matched to the parton shower following the MLM [22] (FxFx [23]) prescription for LO (NLO) samples.”
Identification of heavy, energetic, hadronically decaying particles using machine-learning techniques (2020, methodology): “Double counting of partons generated using pythia and MadGraph5_amc@nlo is eliminated using the MLM [35] and FxFx [36] matching schemes for the LO and NLO samples, respectively.”
Herwig 7.0/Herwig++ 3.0 release note (2015, methodology): “0 contains interface support for FxFx merging [54], a method for merging multi-jet NLO samples with a parton shower.”
Measurement of the forward Z boson production cross-section in pp collisions at s=7$$ \sqrt{s}=7 $$ TeV (2015, methodology): “The MLM [28] sample has leading-order accuracy for the emission of zero, one or two jets; the FxFx [29] sample has next-to-leading-order (NLO) accuracy for zero- or one-jet emission; and the UNLOPS [30] sample is accurate at NLO for zero- or one-jet emission and accurate at LO for two-jet emission.”
Measurements of Higgs boson properties in the diphoton decay channel with 36 fb$^{-1}$ of $pp$ collision data at $\sqrt{s} = 13$ TeV with the ATLAS detector (2018, neutral): “[46, 105], which includes up to two jets at NLO accuracy using the FxFx merging scheme [106].”
Herwig 7.2 release note (2019, methodology): “ulation of resolved photon processes. 9.2 FxFx The FxFx merging module was introduced in [1] to provide support of the NLO multi-jet merging method Johannes Bellm et al.: Herwig 7.2 Release Note 5 of [26], via Les Houches-accord event (LHE) les generated by MadGraph 5/aMC@NLO [27]. In Herwig 7.2 thi”
Combined search for electroweak production of charginos and neutralinos in proton-proton collisions at $\sqrt{s} =$ 13 TeV (2018, methodology): “A double counting of the partons generated with MadGraph5 amc@nlo and those with pythia is removed using the MLM [76] and the FxFx [77] matching schemes, in the LO and NLO samples, respectively.”
Identification of heavy-flavour jets with the CMS detector in pp collisions at 13 TeV (2017, methodology): “2 generator [22], including MadSpin [23] and the FxFx merging scheme [24] between jets from matrix element calculations and the parton shower description, or with the powheg 2.”