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Related papers: NLO matrix elements and truncated showers

200 papers

We discuss an extension of matrix element plus parton shower merging at leading and next-to-leading order. The algorithm does preserve inclusive cross sections at the respective input order. This constraint avoids potentially large…

High Energy Physics - Phenomenology · Physics 2013-07-03 Simon Plätzer

We present results for the QCD production of Z/{\gamma} + 2 jets matched with parton showers using the POWHEG method. Some technicalities relevant for the merging of NLO corrections for this process with parton showers are discussed, and…

High Energy Physics - Phenomenology · Physics 2015-06-04 Emanuele Re

A new implementation of the POWHEG method into the Monte-Carlo event generator Sherpa is presented, focusing on processes with a simple colour structure. Results for a variety of processes, namely e+e- to hadrons, deep-inelastic…

High Energy Physics - Phenomenology · Physics 2011-05-18 Stefan Hoeche , Frank Krauss , Marek Schonherr , Frank Siegert

I review recent developments in POWHEG, a method for interfacing parton-shower generators with NLO QCD computations. I illustrate recent progress in understanding several features of the method, and in clarifying similarity and differences…

High Energy Physics - Phenomenology · Physics 2010-01-18 P. Nason

After an introduction to event generators we give an overview of developments in the field of joining matrix elements with parton showers. Starting with matrix element corrections, we also discuss implementations that match LO and NLO…

High Energy Physics - Phenomenology · Physics 2007-05-23 Stefan Gieseke

A modified version of the CKKW matrix element merging algorithm is presented, suitable for use in an angular-ordered parton shower, using truncated showers and forced splittings. The algorithm is implemented in the Herwig++ Monte Carlo…

High Energy Physics - Phenomenology · Physics 2009-11-13 Keith Hamilton , Peter Richardson , Jon Tully

We introduce a twiki page with collections of generated Monte Carlo event samples in proton-proton collisions at LHC energies including a heavy quark-antiquark pair in the final state. These samples are generated with the POWHEG method and…

High Energy Physics - Phenomenology · Physics 2011-11-08 M. V. Garzelli , Adam Kardos , Zoltán Trócsányi

We present an implementation of the so-called CKKW-L merging scheme for combining multi-jet tree-level matrix elements with parton showers. The implementation uses the transverse-momentum-ordered shower with interleaved multiple…

High Energy Physics - Phenomenology · Physics 2012-03-27 Leif Lonnblad , Stefan Prestel

We present an implementation of the next-to-leading order vector boson plus one jet production process in hadronic collision in the framework of POWHEG, which is a method to implement NLO calculations within a Shower Monte Carlo context.…

High Energy Physics - Phenomenology · Physics 2011-02-01 Simone Alioli , Paolo Nason , Carlo Oleari , Emanuele Re

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

The subtraction method for the matching between the matrix element (ME) and parton shower (PS), that has been developed for combining 0-jet and 1-jet production processes in association with electroweak-boson production in hadron…

High Energy Physics - Phenomenology · Physics 2016-06-21 Shigeru Odaka , Norihisa Watanabe , Yoshimasa Kurihara

A new method to construct event-generators based on next-to-leading order QCD matrix-elements and leading-logarithmic parton showers is proposed. Matrix elements of loop diagrams as well as those of a tree level can be generated using an…

High Energy Physics - Phenomenology · Physics 2007-05-23 Y. Kurihara

We present a simulation program for the production of a pair of W bosons in association with a jet, that can be used in conjunction with general-purpose shower Monte Carlo generators, according to the POWHEG method. We have further adapted…

High Energy Physics - Phenomenology · Physics 2016-10-12 Keith Hamilton , Tom Melia , Pier Francesco Monni , Emanuele Re , Giulia Zanderighi

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…

The next-to-leading order (NLO) corrections to Drell-Yan slepton pair production are merged with parton shower evolution via the POWHEG method in Herwig++. The NLO corrections at the level of event generation alter the shape of observables…

High Energy Physics - Phenomenology · Physics 2012-08-02 Ilan Fridman-Rojas , Peter Richardson

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 give a status report on the automation of next-to-leading order processes within the Monte Carlo event generator WHIZARD, using GoSam and OpenLoops as provider for one-loop matrix elements. To deal with divergences, WHIZARD uses…

High Energy Physics - Phenomenology · Physics 2016-12-21 J. Reuter , B. Chokoufe , A. Hoang , W. Kilian , M. Stahlhofen , T. Teubner , C. Weiss

The positive weight next-to-leading-order (NLO) matching scheme (POWHEG) is applied to Drell-Yan vector boson production in the Herwig++ Monte Carlo event generator. This approach consistently combines the NLO calculation and parton shower…

High Energy Physics - Phenomenology · Physics 2008-11-26 Keith Hamilton , Peter Richardson , Jon Tully

We present an implementation of the calculation of the production of W^+W^+ plus two jets at hadron colliders, at next-to-leading order (NLO) in QCD, in the POWHEG framework, which is a method that allows the interfacing of NLO calculations…

High Energy Physics - Phenomenology · Physics 2015-05-27 Tom Melia , Paolo Nason , Raoul Rontsch , Giulia Zanderighi