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Related papers: QCD matrix elements + parton showers: The NLO case

200 papers

We present a new calculation for the production of isolated photon pairs at the LHC with NNLL$'_{\mathcal{T}_0}$+NNLO accuracy. This is the first implementation within the GENEVA Monte Carlo framework of a process with a nontrivial…

High Energy Physics - Phenomenology · Physics 2021-04-21 Simone Alioli , Alessandro Broggio , Alessandro Gavardi , Stefan Kallweit , Matthew A. Lim , Riccardo Nagar , Davide Napoletano , Luca Rottoli

A recent global analysis of direct photon production at hadron collider and fixed target experiments has noted a disturbing trend of disagreement between next-to-leading-order (NLO) calculations and data. The conjecture has been made that…

High Energy Physics - Phenomenology · Physics 2009-10-28 Howard Baer , Mary Hall Reno

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

We present predictions for the production cross section of a Standard Model Z0-boson in association with a top-antitop pair at the next-to-leading order accuracy in QCD, matched with shower Monte Carlo programs to evolve the system down to…

High Energy Physics - Phenomenology · Physics 2012-04-23 M. V. Garzelli , A. Kardos , C. G. Papadopoulos , Z. Trocsanyi

Extending previous work on the predictions for the production of supersymmetric (SUSY) particles at the LHC, we present the fully differential calculation of the next-to-leading order (NLO) SUSY-QCD corrections to the production of squark…

High Energy Physics - Phenomenology · Physics 2015-06-22 Ryan Gavin , Christian Hangst , Michael Krämer , Margarete Mühlleitner , Mathieu Pellen , Eva Popenda , Michael Spira

We briefly summarize the Nagy-Soper parton shower and the MC@NLO-like matching scheme. Results obtained using HELAC-NLO framework in conjunction with DEDUCTOR for top quark pair production in association with one hard jet at the LHC are…

High Energy Physics - Phenomenology · Physics 2015-10-09 Manfred Kraus

We discuss the theoretical bases that underpin the automation of the computations of tree-level and next-to-leading order cross sections, of their matching to parton shower simulations, and of the merging of matched samples that differ by…

High Energy Physics - Phenomenology · Physics 2015-06-19 J. Alwall , R. Frederix , S. Frixione , V. Hirschi , F. Maltoni , O. Mattelaer , H. -S. Shao , T. Stelzer , P. Torrielli , M. Zaro

We study the hadroproduction of a $Wb$ pair in association with a light jet, focusing on the dominant $t$-channel contribution and including exactly at the matrix-element level all non-resonant and off-shell effects induced by the finite…

High Energy Physics - Phenomenology · Physics 2016-06-29 Rikkert Frederix , Stefano Frixione , Andrew S. Papanastasiou , Stefan Prestel , Paolo Torrielli

We present a simple formalism for the evolution of timelike jets in which tree-level matrix element corrections can be systematically incorporated, up to arbitrary parton multiplicities and over all of phase space, in a way that…

High Energy Physics - Phenomenology · Physics 2013-08-06 W. T. Giele , D. A. Kosower , P. Z. Skands

The accuracy of parton-shower simulations is often a limiting factor in the interpretation of data from high-energy colliders. We present the first formulation of parton showers with accuracy one order beyond state-of-the-art…

High Energy Physics - Phenomenology · Physics 2024-06-14 Silvia Ferrario Ravasio , Keith Hamilton , Alexander Karlberg , Gavin P. Salam , Ludovic Scyboz , Gregory Soyez

We introduce an improvement to the FxFx matrix element merging procedure for $pp\to t \bar t W$ production at NLO in QCD with one and/or two additional jets. The main modification is an improved treatment of jets that are not…

High Energy Physics - Phenomenology · Physics 2021-11-24 Rikkert Frederix , Ioannis Tsinikos

This paper assesses the uncertainties inherent to parton shower simulations at double logarithmic accuracy, with a focus on their impact on jet quenching studies in high-energy heavy-ion collisions. For that purpose, we developed a massless…

High Energy Physics - Phenomenology · Physics 2025-07-29 Carlota Andres , Liliana Apolinário , Néstor Armesto , André Cordeiro , Fabio Dominguez , José Guilherme Milhano

We report the results of a computation of the full next-to-leading order QCD corrections to the production of two $b\bar{b}$ pairs at the LHC. This calculation at the parton level provides predictions for well separated $b$-jets. The…

High Energy Physics - Phenomenology · Physics 2011-09-29 Nicolas Greiner , Alberto Guffanti , Thomas Reiter , Jürgen Reuter

We present methods to achieve NLL+NLO accurate parton showering for processes with two coloured legs: neutral- and charged-current Drell-Yan, and Higgs production in $pp$ collisions, as well as DIS and $e^+e^-$ to jets. The methods include…

We present a detailed technical derivation of matching conditions at next-to-next-to-leading order in the sectorised VINCIA parton shower, by considering leading-colour 2-, 3- and 4-jet rates in hadronic Z-boson decays. In particular, we…

High Energy Physics - Phenomenology · Physics 2025-11-10 Basem Kamal El-Menoufi , Christian T. Preuss , Ludovic Scyboz , Peter Skands

The decade-old technique of combining NLO-corrected hard process with LO-level parton shower Monte Carlo is now mature and used in practice of the QCD calculations in the LHC data analysis. The next step, its extension to an NNLO-corrected…

High Energy Physics - Phenomenology · Physics 2015-06-17 S. Jadach , A. Kusina , W. Placzek , M. Skrzypek

The possibility of an improvement of current NLO Monte Carlo event generators by means of choosing a suitable factorization scheme is studied. The optimal factorization scheme for combining initial state parton showers and NLO hard…

High Energy Physics - Phenomenology · Physics 2012-12-12 Karel Kolar

We present a first application of a previously published method for the computation of QCD processes that is accurate at next-to-leading order, and that can be interfaced consistently to standard shower Monte Carlo programs. We have…

High Energy Physics - Phenomenology · Physics 2009-11-11 Paolo Nason , Giovanni Ridolfi

Monte Carlo event generators for hard hadronic collisions depend on the evolution of parton showers backwards from a high-scale subprocess to the hadronization scale. The evolution is treated as a branching process with a sequence of…

High Energy Physics - Phenomenology · Physics 2024-04-16 Stefano Frixione , Bryan R. Webber

We extend the multi-purpose Monte-Carlo event generator Sherpa to include processes in deeply inelastic lepton-nucleon scattering. Hadronic final states in this kinematical setting are characterised by the presence of multiple kinematical…

High Energy Physics - Phenomenology · Physics 2015-09-22 Tancredi Carli , Thomas Gehrmann , Stefan Höche