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Related papers: Matching Tree-Level Matrix Elements with Interleav…

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We present a simple formalism for the evolution of timelike jets in which tree-level matrix element corrections can be systematically incorporated, up to arbitrary parton multiplicities and over all of phase space, in a way that…

High Energy Physics - Phenomenology · Physics 2013-08-06 W. T. Giele , D. A. Kosower , P. Z. Skands

We extend the lowest-order matching of tree-level matrix elements with parton showers to give a complete description at the next higher perturbative accuracy in alpha_s at both small and large jet resolutions, which has not been achieved so…

We aim to improve the modelling of deep inelastic scattering by implementing multi-jet merging capabilities in Vincia parton shower in the general-purpose Monte Carlo event generator, Pythia. Merging allows to combine event samples of…

High Energy Physics - Phenomenology · Physics 2024-08-16 Joni Laulainen , Ilkka Helenius , Christian T. Preuss

We introduce a method for matching the neutral-current deep inelastic scattering process with parton showers at first order in the strong coupling. This multiplicative matching is achieved by reweighting leading-order Born-level events and…

High Energy Physics - Phenomenology · Physics 2026-05-13 Ilkka Helenius , Joni O. Laulainen , Christian T. Preuss

One of the main theoretical systematics in studies of final states with large jet multiplicities at high-energy hadron colliders is associated with the merging of QCD parton showers and hard-scattering matrix elements. We present a method…

High Energy Physics - Phenomenology · Physics 2022-09-28 A. Bermudez Martinez , F. Hautmann , M. L. Mangano

In this short note, I introduce to essential conceptual features and main building blocks of matrix element merging algorithms, operating on fixed order calculations both at leading order and next-to-leading order. The intention is purely…

High Energy Physics - Phenomenology · Physics 2015-03-30 Thomas Rössler

An algorithm is presented that combines the ME+PS approach to merge sequences of tree-level matrix elements into inclusive event samples with the POWHEG method, which combines exact next-to-leading order matrix elements with parton showers.…

High Energy Physics - Phenomenology · Physics 2010-09-09 Stefan Hoeche , Frank Krauss , Marek Schonherr , Frank Siegert

We propose a sophisticated framework for high-energy hadronic collisions, wherein different QCD physics processes are interleaved in a common sequence of falling transverse-momentum values. Thereby phase-space competition is introduced…

High Energy Physics - Phenomenology · Physics 2016-09-06 T. Sjöstrand , P. Skands

The second-order QCD matrix elements give a very good agreement with experimental data on the angular distributions of the four-jet events in e+e- collisions at the Z0 resonance energy. Unfortunately the description of the sub-jet structure…

High Energy Physics - Phenomenology · Physics 2007-05-23 Johan André

In recent times the algorithms for the simulation of hadronic collisions have been subject to two substantial improvements: the inclusion, within parton showering, of exact higher order tree level matrix elements (MEPS) and, separately,…

High Energy Physics - Phenomenology · Physics 2015-03-14 Keith Hamilton , Paolo Nason

We propose a general approach for the description of multijet events in the framework of QCD event generators. We introduce a new algorithm to match parton showers and arbitrary matrix elements for the production of any number of jets via…

High Energy Physics - Phenomenology · Physics 2009-10-31 F. Krauss , R. Kuhn , G. Soff

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- collisions and for the hadroproduction of W bosons and…

High Energy Physics - Phenomenology · Physics 2011-05-05 Stephen Mrenna , Peter Richardson

We study the matching of multijet matrix elements and shower evolution in the case of top production in hadronic collisions at the Tevatron and at the LHC. We present the results of the matching algorithm implemented in the ALPGEN Monte…

High Energy Physics - Phenomenology · Physics 2010-10-27 Michelangelo L. Mangano , Mauro Moretti , Fulvio Piccinini , Michele Treccani

We have implemented a systematic procedure for combining parton shower algorithms with next-to-leading order QCD calculations for the case of jet production in deep-inelastic electron-proton scattering. Using this method we have computed…

High Energy Physics - Phenomenology · Physics 2009-11-07 B. Pötter , T. Schörner

The method to merge matrix elements for multi particle production and parton showers in electron-positron annihilations and hadronic collisions and its implementation into the new event generator SHERPA is described in detail. Examples…

High Energy Physics - Phenomenology · Physics 2009-11-11 Andreas Schaelicke , Frank Krauss

QCD predictions for final states with multiple jets in hadron collisions make use of multi-jet merging methods, which allow one to combine consistently the contributions from hard scattering matrix elements with different parton…

High Energy Physics - Phenomenology · Physics 2022-08-15 Aron Mees van Kampen

In this work we present the implementation of generators for W and Z bosons in association with two jets interfaced to parton showers using the POWHEG BOX. We incorporate matrix elements from the parton-level Monte Carlo program MCFM in the…

High Energy Physics - Phenomenology · Physics 2015-06-15 John M. Campbell , R. Keith Ellis , Paolo Nason , Giulia Zanderighi

We propose a simple scheme to start a parton-shower evolution description from a given jet configuration in $e^+ e^-$ annihilation events. This allows a convenient combination of the full angular information content of matrix elements with…

High Energy Physics - Phenomenology · Physics 2011-01-13 J. André , T. Sjöstrand

One of the most important developments in Monte Carlo simulation of collider events for the LHC has been the arrival of schemes and codes for matching of parton showers to matrix elements calculated at next-to-leading order in the QCD…

High Energy Physics - Phenomenology · Physics 2017-12-21 Andy Buckley , Debottam Bakshi Gupta

The merging procedure of tree-level matrix elements and the subsequent parton shower as implemented in the new event generator SHERPA will be validated for the example of W/Z+jets production at the Tevatron. Comparisons with results…

High Energy Physics - Phenomenology · Physics 2011-03-23 Frank Krauss , Andreas Schaelicke , Steffen Schumann , Gerhard Soff