English
Related papers

Related papers: Multi-jet merging with NLO matrix elements

200 papers

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

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 propose an extension of matrix element plus parton shower merging at tree level to preserve inclusive cross sections obtained from the merged and showered sample. Implementing this constraint generates approximate next-to-leading order…

High Energy Physics - Phenomenology · Physics 2015-06-12 Simon Platzer

We propose a new approach for combining next-to-leading order (NLO) and parton shower (PS) calculations so as to obtain three core features: (a) applicability to general showers, as with the MCatNLO and POWHEG methods; (b) positive-weight…

High Energy Physics - Phenomenology · Physics 2022-02-02 Paolo Nason , Gavin P. Salam

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

In this talk, we discuss recent developments in combining parton showers and fixed-order calculations. We focus on the UNNLOPS method for matching next-to-next-to-leading order computations to the parton shower, and we present results from…

High Energy Physics - Phenomenology · Physics 2015-07-21 Stefan Hoeche , Ye Li , Stefan Prestel

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

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

To explore the interplay of NLO matching and next-to-leading logarithmic (NLL) parton showers, we consider the simplest case of $\gamma^*$ and Higgs-boson decays to $q\bar q$ and $gg$ respectively. Not only should shower NLL accuracy be…

High Energy Physics - Phenomenology · Physics 2023-10-25 Keith Hamilton , Alexander Karlberg , Gavin P. Salam , Ludovic Scyboz , Rob Verheyen

We review the methods developed for combining the parton shower approximation to QCD with fixed-order perturbation theory, in such a way as to achieve next-to-leading-order (NLO) accuracy for inclusive observables. This has made it possible…

High Energy Physics - Phenomenology · Physics 2015-06-04 Paolo Nason , Bryan Webber

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 extend earlier schemes for merging tree-level matrix elements with parton showers to include also merging with one-loop matrix elements. In this paper we make a first study on how to include one-loop corrections, not only for events with…

High Energy Physics - Phenomenology · Physics 2009-02-02 Nils Lavesson , Leif Lonnblad

Higher order calculations are necessary to predict and describe measurements in high energy collider physics. In recent years multiple approaches to combine multiple next-to-leading (NLO) order corrections with parton showers had been…

High Energy Physics - Phenomenology · Physics 2016-07-08 Johannes Bellm

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 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

We compare different procedures for combining fixed-order tree-level matrix-element generators with parton showers. We use the case of W-production at the Tevatron and the LHC to compare different implementations of the so-called CKKW and…

We consider the POWHEG generator for a H/W/Z boson plus one jet, augmented with the recently proposed MiNLO method for the choice of scales and the inclusion of Sudakov form factors. Within this framework, the generator covers all the…

High Energy Physics - Phenomenology · Physics 2015-06-12 Keith Hamilton , Paolo Nason , Carlo Oleari , Giulia Zanderighi

We introduce multi-jet merging for deep inelastic scattering in the Vincia parton shower in the Monte Carlo event generator Pythia 8. Merging combines event samples of different parton multiplicities with logarithmically enhanced…

High Energy Physics - Phenomenology · Physics 2025-06-10 Ilkka Helenius , Joni O. Laulainen , Christian T. Preuss

A method is suggested to combine tree level QCD matrix for the production of multi jet final states and the parton shower in hadronic interactions. The method follows closely an algorithm developed recently for the case of $e^+e^-$…

High Energy Physics - Phenomenology · Physics 2011-05-05 F. Krauss

The MC@NLO method as implemented in the Sherpa MC generator is presented using the production of W-bosons in conjunction with up to three jets as an example. Corresponding results computed at next-to leading order in QCD and including…

High Energy Physics - Phenomenology · Physics 2012-06-22 Frank Siegert , Stefan Hoeche , Frank Krauss , Marek Schonherr