Matching Matrix Elements and Parton Showers with HERWIG and PYTHIA

By Stephen Mrenna, Peter Wilson Fermi National Accelerator Laboratory, Theory Division, Cern. 2003

191 citations recorded by the source corpus.

We report on our exploration of matching matrix element calculations with the parton-shower models contained in the event generators HERWIG and PYTHIA. We describe results for e + e i collisions and for the hadroproduction of W bosons and Drell- Yan pairs. We compare methods based on (1) a strict implementation of ideas proposed by Catani et al., (2) a generalization based on using the internal Sudakov form factors of HERWIG and PYTHIA, and (3) a simpler proposal of M. Mangano. Where appropriate, we show the dependence on various choices of scales and clustering that do not afiect the soft and collinear limits of the predictions, but have phenomenological implications. Finally, we comment on how to use these results to state systematic errors on the theoretical predictions.

Subfields: Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/11c9aef5b0dd1e52b0a21f5fc8882e51e864b329

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Citations in the corpus

A comprehensive approach to new physics simulations (2009, methodology): “Here also, significant progress has been made in the development of matching algorithms such as that by Catani, Krauss, Kuhn and Webber (CKKW) [30, 31, 32], Mangano (MLM) [33] and others [34, 35, 36], in their comparison [37, 38] and application to SM [33, 39] and BSM [40] processes.”
Tuning PYTHIA 8.1: the Monash 2013 tune (2014, methodology): “Especially in the latter context of matrix-element matching, we expect that in many cases PYTHIA 8 will be used together with codes such as ALPGEN [127], MADGRAPH [128], aMCatNLO [129], or POWHEG [130], either using the matching algorithms of those programs themselves, or via any of PYTHIA’s several”
General-purpose event generators for LHC physics (2011, methodology): “In addition, more pragmatic versions of the CKKW(-L) merging have been introduced, with less focus on the formal accuracy; the MLM approach by Mangano [72] (see also [73]) and the Pseudo-Shower algorithm by Mrenna and Richardson[74].”
Event generation with SHERPA 1.1 (2008, background): “[89,23,24], and the first dedicated experimental analyses on comparing these improved Monte Carlo predictions with actual data have been presented [90,91,92].”
QCD Radiation in the Production of Heavy Colored Particles at the LHC (2008, result): “These different procedures are in substantial agreement and give consistent results at hadron colliders [13, 14].”
The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations (2014, unknown): “[145–148, 192–197]).”
MadGraph 5: going beyond (2011, methodology): “Here again, signiﬁcant progress has been made in the development of merging algorithms, such as CKKW and MLM merging [36, 37, 38, 39, 40, 41, 42], and in their comparison [43, 44], with applications to SM [45, 39, 46] and to BSM [47] processes.”
MadGraph/MadEvent v4: The New Web Generation (2007, methodology): “It should also be noted that a similar matching method for matching of MadEvent matrix elements to Pythia showers has been implemented independently by Mrenna [15] and has been successfully used to describe Tevatron W+jets backgrounds.”