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Related papers: Multivariable evolution in parton showers with ini…

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We outline a new formalism for dipole-type parton showers which maintain exact energy-momentum conservation at each step of the evolution. Particular emphasis is put on the coherence properties, the level at which recoil effects do enter…

High Energy Physics - Phenomenology · Physics 2011-01-17 Simon Platzer , Stefan Gieseke

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

A new family of parameters intended for composition studies is presented. They make exclusive use of surface data combining the information from the total signal at each triggered detector and the array geometry. We perform an analytical…

High Energy Astrophysical Phenomena · Physics 2009-08-03 G. Ros , A. D. Supanitsky , G. A. Medina-Tanco , L. del Peral , M. D. Rodriguez-Frias

In a companion publication, we have explored how to examine the summation of large logarithms in a parton shower. Here, we apply this general program to the thrust distribution in electron-positron annihilation, using several shower…

High Energy Physics - Phenomenology · Physics 2020-11-17 Zoltan Nagy , Davison E. Soper

Parton shower Monte Carlo event generators in which the shower evolves from hard splittings to soft splittings generally use the leading color approximation, which is the leading term in an expansion in powers of $1/N_c^2$, where $N_c = 3$…

High Energy Physics - Phenomenology · Physics 2015-06-04 Zoltán Nagy , Davison E. Soper

We consider a model of transverse momentum production in which non-perturbative smearing takes place throughout the perturbative evolution, by a simple modification to an initial state parton shower algorithm. Using this as the important…

High Energy Physics - Phenomenology · Physics 2009-02-18 Stefan Gieseke , Michael H. Seymour , Andrzej Siodmok

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

A new family of parameters intended for composition studies in cosmic ray surface array detectors is proposed. The application of this technique to different array layout designs has been analyzed. The parameters make exclusive use of…

High Energy Astrophysical Phenomena · Physics 2015-03-19 G. Ros , A. D. Supanitsky , G. A. Medina-Tanco , L. del Peral , J. C. D'Olivo , M. D. Rodríguez-Frías

Starting with the interpretation of parton evolution with rapidity as a branching-diffusion process, we describe the different kinds of fluctuations of the density of partons which affect the properties of QCD scattering amplitudes at…

High Energy Physics - Phenomenology · Physics 2014-09-16 A. H. Mueller , S. Munier

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

We report on the implementation of an interface between the SANC generator framework for Drell-Yan hard processes, which includes next-to-leading order electroweak (NLO EW) corrections, and the Herwig++ and Pythia8 QCD parton shower Monte…

High Energy Physics - Phenomenology · Physics 2015-05-20 P. Richardson , R. R. Sadykov , A. A. Sapronov , M. H. Seymour , P. Z. Skands

We relate the fragmentation functions of partons into mesons and baryons in the framework of recombination of shower partons. The results are in reasonable agreement with the data. The implication is that the meson and baryon fragmentation…

Nuclear Theory · Physics 2009-11-11 Rudolph C. Hwa , C. B. Yang

We describe an algorithm for improving subsequent parton shower emissions by full SU(3) color correlations in the framework of a dipole-type shower. As a proof of concept, we present results from the first implementation of such an…

High Energy Physics - Phenomenology · Physics 2015-06-03 Simon Platzer , Malin Sjodahl

We give a prescription for attaching parton showers to next-to-leading order (NLO) partonic jet cross sections in electron-positron annihilation. Our method effectively extends to NLO the scheme of Catani, Krauss, Kuhn, and Webber for…

High Energy Physics - Phenomenology · Physics 2007-05-23 Zoltan Nagy , Davison E. Soper

The Drell-Yan process is a standard tool for probing the partonic structure of hadrons. Since the process proceeds through a quark-antiquark annihilation, Drell-Yan scattering possesses a unique ability to selectively probe sea…

Nuclear Experiment · Physics 2008-11-26 Paul E. Reimer

We study the logarithmic accuracy of angular-ordered parton showers by considering the singular limits of multiple emission matrix elements. This allows us to consider different choices for the evolution variable and propose a new choice…

High Energy Physics - Phenomenology · Physics 2020-03-27 Gavin Bewick , Silvia Ferrario Ravasio , Peter Richardson , Michael H. Seymour

A new framework is sketched for the treatment of the hadronisation of a highly-virtual quark and anti-quark jet pair created in electron-positron annihilations. As in such a case, factorization theorem does not work, a new scale-evolution…

High Energy Physics - Phenomenology · Physics 2017-07-04 Karoly Urmossy

It has been argued recently that parton showers based on colour dipoles conflict with collinear factorization and do not lead to the correct DGLAP equation. We show that this conclusion is based on an inappropriate assumption, namely the…

High Energy Physics - Phenomenology · Physics 2009-11-20 Peter Skands , Stefan Weinzierl

We develop the notion of shower partons and determine their distributions in jets in the framework of the recombination model. The shower parton distributions obtained render a good fit of the fragmentation functions. We then illustrate the…

High Energy Physics - Phenomenology · Physics 2011-02-01 Rudolph C. Hwa , C. B. Yang

We present an implementation of a parton shower algorithm for hadron colliders and electron-positron colliders based on the dipole factorisation formulae. The algorithm treats initial-state partons on equal footing with final-state partons.…

High Energy Physics - Phenomenology · Physics 2008-11-26 Michael Dinsdale , Marko Ternick , Stefan Weinzierl