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Related papers: QCD matrix elements + parton showers: The NLO case

200 papers

The concept of new methodology of adding QCD NLO corrections in the initial state Monte Carlo parton shower (hard process part) is tested numerically using, as an example, the process of the heavy boson production at hadron--hadron…

High Energy Physics - Phenomenology · Physics 2013-01-03 S. Jadach , M. Jezabek , A. Kusina , W. Placzek , M. Skrzypek

The merging procedure of tree-level matrix elements with the subsequent parton shower as implemented in SHERPA will be studied for the example of W boson pair production at the Fermilab Tevatron. Comparisons with fixed order calculations at…

High Energy Physics - Phenomenology · Physics 2011-03-23 T. Gleisberg , F. Krauss , A. Schaelicke , S. Schumann , J. Winter

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 investigate the effects of combining next-to-leading order QCD results with parton-shower effects in $W^+W^-jj$ production via vector-boson fusion including leptonic decays. Using the Herwig 7 framework interfaced to VBFNLO 3, we compare…

High Energy Physics - Phenomenology · Physics 2016-07-04 Michael Rauch , Simon Plätzer

In the algorithm presented here, the ME+PS approach to merge samples of tree-level matrix elements into inclusive event samples is combined with the POWHEG method, which includes exact next-to-leading order matrix elements in the parton…

High Energy Physics - Phenomenology · Physics 2011-09-28 Frank Siegert , Stefan Hoeche , Frank Krauss , Marek Schonherr

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 make the connection between certain deep learning architectures and the renormalisation group explicit in the context of QCD by using a deep learning network to construct a toy parton shower model. The model aims to describe…

High Energy Physics - Phenomenology · Physics 2018-12-26 James William Monk

We present an MC@NLO-like matching of next-to-leading order QCD calculations with the Nagy-Soper parton shower. An implementation of the algorithm within the HELAC-DIPOLES Monte Carlo generator is used to address the uncertainties and…

High Energy Physics - Phenomenology · Physics 2015-06-15 M. Czakon , H. B. Hartanto , M. Kraus , M. Worek

Programs that calculate observables in quantum chromodynamics at next-to-leading order typically generate events that consist of partons rather than hadrons -- and just a few partons at that. These programs would be much more useful if the…

High Energy Physics - Phenomenology · Physics 2009-11-10 Davison E. Soper

We calculate the production of a W boson in association with up to two jets including at least one b-jet to next-to-leading order (NLO) in QCD at the CERN Large Hadron Collider with 7 TeV center-of-mass energy. Both exclusive and inclusive…

High Energy Physics - Phenomenology · Physics 2013-03-20 F. Caola , J. M. Campbell , F. Febres Cordero , L. Reina , D. Wackeroth

We study in this paper the production, in hadronic collisions, of final states with W gauge bosons, heavy quark pairs and n extra jets (with n up to 4). The complete partonic tree-level QCD matrix elements are evaluated using the ALPHA…

High Energy Physics - Phenomenology · Physics 2008-11-26 Michelangelo L. Mangano , Mauro Moretti , Roberto Pittau

The new methodology of adding QCD NLO corrections in the initial state Monte Carlo parton shower (hard process part) is presented using process of the heavy boson production at the LHC as an example. Despite the simplified model of the…

High Energy Physics - Phenomenology · Physics 2012-10-31 S. Jadach , A. Kusina , M. Skrzypek , M. Slawinska

We present a parameter-free scheme to combine fixed-order multi-jet results with parton-shower evolution. The scheme produces jet cross sections with leading-order accuracy in the complete phase space of multiple emissions, resumming large…

High Energy Physics - Phenomenology · Physics 2017-10-11 Nadine Fischer , Stefan Prestel

We introduce the first family of parton showers that achieve next-to-leading logarithmic (NLL) accuracy for processes involving a $t$-channel exchange of a colour-singlet, and embed them in the PanScales framework. These showers are…

High Energy Physics - Phenomenology · Physics 2024-02-06 Melissa van Beekveld , Silvia Ferrario Ravasio

In this article we illustrate how event weights for jet events can be calculated efficiently at next-to-leading order (NLO) accuracy in QCD. This is a crucial prerequisite for the application of the Matrix Element Method in NLO. We modify…

High Energy Physics - Phenomenology · Physics 2015-09-18 Till Martini , Peter Uwer

The pair production of squarks is one of the main search channels for supersymmetry at the LHC. We present a fully differential calculation of the next-to-leading order (NLO) SUSY-QCD corrections to the on-shell production of a pair of…

High Energy Physics - Phenomenology · Physics 2014-02-17 Ryan Gavin , Christian Hangst , Michael Krämer , Margarete Mühlleitner , Mathieu Pellen , Eva Popenda , Michael Spira

We compare a NLO W gamma matrix element generator with the leading order calculation in Pythia . A matching scheme between a next-to-leading order W gamma matrix element generator by Baur et. al. and the Pythia parton shower is presented.…

High Energy Physics - Phenomenology · Physics 2010-02-24 D. Majumder , K. Mazumdar , T. Sjostrand

We apply the MC@NLO approach to the process of heavy flavour hadroproduction. MC@NLO is a method for matching next-to-leading order (NLO) QCD calculations and parton shower Monte Carlo (MC) simulations, with the following features: fully…

High Energy Physics - Phenomenology · Physics 2009-11-10 S. Frixione , P. Nason , B. R. Webber

We compute the production cross section of a top-antitop pair in association with a jet at hadron colliders at next-to-leading order accuracy matched with parton shower algorithms to make predictions at the hadron level. The parton shower…

High Energy Physics - Phenomenology · Physics 2015-03-17 Adam Kardos , Costas Papadopoulos , Zoltan Trocsanyi

The leptonic decays of the heavy gauge bosons W and/or Z provide a clear experimental signature at hadron colliders. The production of accompanying jets is an excellent signal to probe QCD, while also being the main background to many…

High Energy Physics - Phenomenology · Physics 2015-03-18 Flavia A. Dias , Emily Nurse , Gavin Hesketh