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Related papers: Combining QCD Matrix Elements and Parton Showers

200 papers

We derive a new method for initial-state collinear showering in Monte-Carlo event generators which is based on the use of unintegrated parton correlation functions. Combined with a previously derived method for final-state showering, the…

High Energy Physics - Phenomenology · Physics 2008-11-26 John C. Collins , Xiaomin Zu

Parton showers in Monte Carlo event generators reflect to a certain accuracy our understanding of QCD radiation at all orders. For observables sensitive to interjet energy flow in well defined regions of phase space, it has been known for…

High Energy Physics - Phenomenology · Physics 2007-06-19 Mrinal Dasgupta

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

QCD jets are considered important probes for quark gluon plasma created in collisions of nuclei at high energies. Their parton showers are significantly altered if they develop inside of a deconfined medium. Hadronization of jets is also…

Shower Monte Carlo event generators have played an important role in particle physics. Modern experiments would hardly be possible without them. In this talk I discuss how QCD physics is incorporated into the mathematical structure of these…

High Energy Physics - Phenomenology · Physics 2017-08-23 Zoltan Nagy , Davison E. Soper

We propose to model hadronization of parton showers in QCD jets through a hybrid approach involving quark recombination and string fragmentation. This is achieved by allowing gluons at the end of the perturbative shower evolution to undergo…

Nuclear Theory · Physics 2016-04-20 Kyong Chol Han , Rainer J. Fries , Che Ming Ko

Transverse-momentum dependent parton distributions can be introduced gauge-invariantly in QCD from high-energy factorization. We discuss Monte Carlo applications of these distributions to parton showers and jet physics, with a view to the…

High Energy Physics - Phenomenology · Physics 2009-02-18 F. Hautmann , H. Jung

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

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 diagram as well as those of a tree level can be generated using an…

High Energy Physics - Phenomenology · Physics 2010-04-05 Y. Kurihara , J. Fujimoto , T. Ishikawa , K. Kato , S. Kawabata , T. Munehisa , H. Tanaka

We present a new formalism for parton shower simulation of QCD jets, which incorporates the following features: invariance under boosts along jet axes, improved treatment of heavy quark fragmentation, angular-ordered evolution with soft…

High Energy Physics - Phenomenology · Physics 2014-11-17 Stefan Gieseke , Philip Stephens , Bryan Webber

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

We present an algorithm to combine multiple matrix elements at LO and NLO with a parton shower. We build on the unitarized merging paradigm. The inclusion of higher orders and multiplicities reduce the scale uncertainties for observables…

High Energy Physics - Phenomenology · Physics 2018-04-18 Johannes Bellm , Stefan Gieseke , Simon Plätzer

The latest progress in calculating electroweak gauge boson production in association with QCD jets at hadron colliders is summarized. Particular emphasis is given to the recently completed QCD one-loop calculations of W+3jets and Wb final…

High Energy Physics - Phenomenology · Physics 2022-03-02 Steffen Schumann

In this talk I gave a brief summary of leading order, next-to-leading order and shower calculations. I discussed the main ideas and approximations of the shower algorithms and the related matching schemes. I tried to focus on QCD issues and…

High Energy Physics - Phenomenology · Physics 2007-06-28 Zoltan Nagy

We specify recursive equations that could be used to generate a lowest order parton shower for hard scattering in hadron-hadron collisions. The formalism is based on the factorization soft and collinear interactions from relatively harder…

High Energy Physics - Phenomenology · Physics 2009-04-22 Zoltan Nagy , Davison E. Soper

The last few years have seen community-wide excitement in the study of jet substructure derived from the inner workings of clustering algorithms. Such efforts have resulted in the design of new observables which are related to partonic…

High Energy Physics - Phenomenology · Physics 2022-09-13 Raghav Kunnawalkam Elayavalli

We present a study of effects of QCD radiation in the production of heavy colored states, employing inclusive multi-jet samples obtained by matching matrix elements and parton showers. We discuss several examples showing that matched…

High Energy Physics - Phenomenology · Physics 2009-06-09 Johan Alwall , Simon de Visscher , Fabio Maltoni

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

With the use of MARTINI, a model which considers evolving QCD jets against a fluid dynamical background, it is shown that the introduction of formation time to the parton shower after the initial hard scattering is essential for a…

High Energy Physics - Phenomenology · Physics 2024-07-30 Rouzbeh Modarresi-Yazdi , Shuzhe Shi , Charles Gale , Sangyong Jeon

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