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Related papers: Implementing the ME+PS merging algorithm

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We propose a method for combining QCD matrix elements and parton showers in Monte Carlo simulations of hadronic final states in $e^+e^-$ annihilation. The matrix element and parton shower domains are separated at some value $y_{ini}$ of the…

High Energy Physics - Phenomenology · Physics 2010-02-03 S. Catani , F. Krauss , R. Kuhn , B. R. Webber

CompHEP, as a partonic event generator, and PYTHIA, as a generator of final states of detectable objects, are interfaced. Thus, integrated tool is proposed for simulation of (almost) arbitrary collision processes at the level of detectable…

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

We revisit the CKKW-L method for merging tree-level matrix elements with parton showers, and amend it with an add/subtract scheme to minimise dependencies on the merging scale. The scheme is constructed to, as far as possible, recover the…

High Energy Physics - Phenomenology · Physics 2015-06-12 Leif Lonnblad , Stefan Prestel

The new version 6.1 of the HERWIG event generator allows one to simulate hadronic final states in electron-positron annihilations using the $O(\alpha_s^2)$ partonic matrix elements (MEs) for $e^+e^-\to q\bar qgg$ and $e^+e^-\to q\bar q…

High Energy Physics - Phenomenology · Physics 2007-05-23 S. Moretti

A new method for combining QCD matrix elements and parton showers in Monte Carlo simulations of hadronic final states is outlined. The aim is to provide at least a leading-order description of all hard multi-jet configurations together with…

High Energy Physics - Phenomenology · Physics 2007-05-23 B. R. Webber

The efficient simulation of multijet final states presents a serious computational task for analyses of LHC data and will be even more so at the HL-LHC. We here discuss means to accelerate the generation of unweighted events based on a…

High Energy Physics - Phenomenology · Physics 2026-03-11 Tim Herrmann , Timo Janßen , Mathis Schenker , Steffen Schumann , Frank Siegert

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

Given the current landscape in experimental high-energy physics, these lectures are focused on applications of event generators for hadron colliders like the Tevatron and LHC. Section 2 contains a first overview of the physics picture and…

High Energy Physics - Phenomenology · Physics 2009-11-30 Torbjörn Sjöstrand

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

In this paper we describe Herwig++ version 2.3, a general-purpose Monte Carlo event generator for the simulation of hard lepton-lepton, lepton-hadron and hadron-hadron collisions. A number of important hard scattering processes are…

High Energy Physics - Phenomenology · Physics 2009-09-29 M. Bahr , S. Gieseke , M. A. Gigg , D. Grellscheid , K. Hamilton , O. Latunde-Dada , S. Platzer , P. Richardson , M. H. Seymour , A. Sherstnev , J. Tully , B. R. Webber

We present a new approach to combine multiple NLO parton-level calculations matched to parton showers into a single inclusive event sample. The method provides a description of hard multi-jet configurations at next-to leading order in the…

High Energy Physics - Phenomenology · Physics 2013-02-14 Thomas Gehrmann , Stefan Hoeche , Frank Krauss , Marek Schonherr , Frank Siegert

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

In this contribution the new event generation framework Sherpa will be presented. It aims at the full simulation of events at current and future high-energy experiments, in particular the LHC. Some results related to the production of jets…

High Energy Physics - Phenomenology · Physics 2008-12-18 T. Gleisberg , S. Hoeche , F. Krauss , A. Schaelicke , S. Schumann , J. Winter

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

We describe the implementation of supersymmetric processes in the HERWIG Monte Carlo event generator. We define relevant parameter and mixing conventions and list the hard scattering matrix elements. Our implementation is based on the…

High Energy Physics - Phenomenology · Physics 2010-04-06 S. Moretti , K. Odagiri , P. Richardson , M. H. Seymour , B. R. Webber

Recent developments in QCD phenomenology have spurred on several improved approaches to Monte Carlo event generation, relative to the post--LEP state of the art. In this brief review, the emphasis is placed on approaches for 1) consistently…

High Energy Physics - Phenomenology · Physics 2009-11-11 Peter Z. Skands

Several methods to improve the parton-shower description of hard processes by an injection of matrix-element-based information have been presented over the years. In this article we study (re)weighting schemes for the first/hardest…

High Energy Physics - Phenomenology · Physics 2015-05-18 Richard Corke , Torbjörn Sjöstrand

We have developed a Monte Carlo event generator for non-resonant diphoton ($\gamma\gamma$) production at hadron collisions in the framework of GR@PPA, which consistently includes additional one-jet production. The jet-matching method…

High Energy Physics - Phenomenology · Physics 2013-05-30 Shigeru Odaka , Yoshimasa Kurihara

We study Matrix Element corrections as implemented in four popular event generators for hadron collisions. We compare PYTHIA, HERWIG, ALPGEN and SHERPA in the Z/gamma* inclusive production at LHC. PYTHIA and HERWIG are able to correct the…

High Energy Physics - Phenomenology · Physics 2009-03-27 P. Lenzi , J. M. Butterworth