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Related papers: Resonance- and Width-aware Parton Shower Evolution…

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We present an implementation of electroweak W+W-jj production at hadron colliders in the POWHEG framework, a method that allows the interfacing of a next-to-leading order QCD calculation with parton shower Monte Carlo programs. We provide…

High Energy Physics - Phenomenology · Physics 2015-06-12 Barbara Jager , Giulia Zanderighi

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

We present the first next-to-leading order matched and multi-jet merged predictions based on the Alaric parton shower. The components needed for infrared subtraction in the S-MC@NLO algorithm are computed analytically for the case of color…

High Energy Physics - Phenomenology · Physics 2025-07-31 Stefan Höche , Frank Krauss , Peter Meinzinger , Daniel Reichelt

We present a general method to match fully differential next-to-next-to-leading (NNLO) calculations to parton shower programs. We discuss in detail the perturbative accuracy criteria a complete NNLO+PS matching has to satisfy. Our method is…

High Energy Physics - Phenomenology · Physics 2015-06-17 Simone Alioli , Christian W. Bauer , Calvin Berggren , Frank J. Tackmann , Jonathan R. Walsh , Saba Zuberi

The increasingly high accuracy of top-quark studies at the LHC calls for a theoretical description of $t\bar t$ production and decay in terms of exact matrix elements for the full $2\to 6$ process that includes the off-shell production and…

High Energy Physics - Phenomenology · Physics 2023-07-31 Tomáš Ježo , Jonas M. Lindert , Stefano Pozzorini

We present a process-independent technique to consistently combine next-to-leading order parton-level calculations of varying jet multiplicity and parton showers. Double counting is avoided by means of a modified truncated shower scheme.…

High Energy Physics - Phenomenology · Physics 2015-06-05 Stefan Hoeche , Frank Krauss , Marek Schonherr , Frank Siegert

We calculate the process $pp\to W^+W^-\to e^+ \nu_e \mu^-\bar{\nu}_\mu$ at NLO QCD, including also effective field theory (EFT) operators mediating the $ggW^+W^-$ interaction, which first occur at dimension eight. We further combine the NLO…

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 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

In this study we tried to emphasize the role parton shower plays in event generation, and in the physics of high energy event generation. We achieved this task by comparing the next-to-leading order and next-to-next-to-leading order results…

High Energy Physics - Phenomenology · Physics 2014-05-08 Hessamoddin Kaveh , Mohammad Ebrahim Zomorrodian

We propose a scheme that could offer a convenient Monte Carlo sampling of next-to-leading-order matrix elements and, at the same time, allow the interfacing of such parton configurations with a parton-shower approach for the estimation of…

High Energy Physics - Phenomenology · Physics 2007-05-23 Christer Friberg , Torbjörn Sjöstrand

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 compute the production cross section of a top-antitop pair in association with a jet at hadron colliders at next-to-leading order accuracy matched with parton shower algorithms to make predictions at the hadron level. The parton shower…

High Energy Physics - Phenomenology · Physics 2015-03-17 Adam Kardos , Costas Papadopoulos , Zoltan Trocsanyi

This paper is a follow-up of Ref.~\cite{Ravasio:2018lzi}, where we studied the impact of next-to-leading order calculations merged with parton shower generators (NLO+PS) of increasing accuracy in the extraction of the top mass at hadron…

High Energy Physics - Phenomenology · Physics 2020-01-08 Silvia Ferrario Ravasio , Tomas Jezo , Paolo Nason , Carlo Oleari

Parton showers are among the most widely used tools in collider physics. Despite their key importance, none so far has been able to demonstrate accuracy beyond a basic level known as leading logarithmic (LL) order, with ensuing limitations…

High Energy Physics - Phenomenology · Physics 2020-08-05 Mrinal Dasgupta , Frédéric A. Dreyer , Keith Hamilton , Pier Francesco Monni , Gavin P. Salam , Gregory Soyez

We consider $Z \gamma$ production in hadronic collisions and present the first computation of next-to-next-to-leading order accurate predictions consistently matched to parton showers (NNLO+PS). Spin correlations, interferences and…

High Energy Physics - Phenomenology · Physics 2021-07-07 Daniele Lombardi , Marius Wiesemann , Giulia Zanderighi

We have implemented two recently proposed dipole shower algorithms that have next-to-leading-logarithmic accuracy at leading colour in the Herwig event generator. We study their properties and compare them to Herwig's existing dipole and…

High Energy Physics - Phenomenology · Physics 2026-05-05 Jack Holguin , Simon Plätzer , Michael H. Seymour , Siddharth Sule

The production of W+ W- b bbar from e+ e- collisions at energies close to the t tbar threshold is dominated by the resonant process with a nearly on-shell t tbar intermediate state. The W b pairs in the final state can also be reached…

High Energy Physics - Phenomenology · Physics 2022-09-21 M. Beneke , B. Jantzen , P. Ruiz-Femenia

Parton shower evolution is given by a renormalization group equation that reflects the infrared behavior of perturbative QCD including color and spin and including quantum interference. With added approximations, such an evolution equation…

High Energy Physics - Phenomenology · Physics 2026-05-13 Zoltan Nagy , Davison E. Soper

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