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QCD and Electroweak Quantum Corrections at the Large Hadron Collider

English title QCD and Electroweak Quantum Corrections at the Large Hadron Collider
Applicant Pozzorini Stefano
Number 153027
Funding scheme SNSF Professorships
Research institution Institut für Theoretische Physik Universität Zürich
Institution of higher education University of Zurich - ZH
Main discipline Theoretical Physics
Start/End 01.10.2014 - 30.09.2016
Approved amount 703'977.00
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All Disciplines (2)

Discipline
Theoretical Physics
Particle Physics

Keywords (11)

QCD; Cross section; NLO; Top quark; LHC; Electroweak interactions; Higgs boson; Jets; multi-particle processes; Standard Model; Background

Lay Summary (German)

Lead
In zukuenftige Tests des Higgs Mechanismus und Suchen nach neuer Physik am CERN Large Hadron Collier (LHC) werden praezise theoretische Simulationen von Teilchenkollisionen eine zunehmend wichtige Rolle spielen. In der ersten Phase dieses Projekts wurde ein neues algorithmische Konzept vorgeschlagen und in das Simulationsprogramm Sherpa+OpenLoops implementiert. Diese neue Methode erlaubt voellig automatisierte Simulationen unerhoerter Effizienz, Komplaexitaet und Flexibilitaet. In diesem Projekt sind weitgehende Funktionalitaetserweiterungen vorgesehen, um Sherpa+OpenLoops zum vollstaendigste Simulationsprogramm in the LHC Aera zu machen.
Lay summary
After the discovery of the Higgs Boson, future measurements at CERN's Large Hadron Collider (LHC) will be aimed at precision tests of the Higgs mechanism, by which all elementary particles acquire their mass, and at searches for new exotic phenomena.  In this context, the precision of theoretical simulations will play an increasingly important role in order to fully exploit the possibility to use LHC data for stringent tests of the Standard Model and alternative theories.  In particular, precise simulations of multi-particle processes will become increasingly important in the high-energy and high-luminosity phase of the LHC experiment.  Thanks to a novel algorithmic concept, which was proposed in the first phase of this project and implemented in the Sherpa+OpenLoops program, such multi-particle simulations can now be performed with an unprecedented degree of efficency and automation for any Standard-Model process with up to (at least) six external particles. This project aims at promoting Sherpa+OpenLoops to the most complete tool for precision simulations in the LHC era. To this end the functionality of OpenLoops and Sherpa will be extended in various new nontrivial directions including: first-order quantum effects associated with electroweak interactions; quantum corrections for complex processes involving the production and subsequent chain-decays of heavy unstable particles; applications to the analysis of various key processes involving top quarks, vector bosons, photons and Higgs bosons at the LHC.  All envisaged improvements will be implemented in a fully flexible and automated way. This will guarantee a very wide range of applicability, and we expect that our tool will be widely used by the experimental community.
Direct link to Lay Summary Last update: 13.10.2014

Responsible applicant and co-applicants

Employees

Publications

Publication
$W^{+}W^{−}$ production at the LHC: fiducial cross sections and distributions in NNLO QCD
Grazzini Massimiliano, Kallweit Stefan, Pozzorini Stefano, Rathlev Dirk, Wiesemann Marius (2016), $W^{+}W^{−}$ production at the LHC: fiducial cross sections and distributions in NNLO QCD, in JHEP, 08, 140-140.
Fast evaluation of theoretical uncertainties with Sherpa and MCgrid
Bothmann Enrico, Schönherr Marek, Schumann Steffen (2016), Fast evaluation of theoretical uncertainties with Sherpa and MCgrid, in XXIII International Workshop on Deep-Inelastic Scattering, DIS2015, PoS, Italy.
Handbook of LHC Higgs Cross Sections: 4. Deciphering the Nature of the Higgs Sector
de Florian D., others (2016), Handbook of LHC Higgs Cross Sections: 4. Deciphering the Nature of the Higgs Sector, CERN report, CERN, geneva.
Higgs + Multi-jets in Gluon Fusion
Greiner Nicolas, Hoeche Stefan, Luisoni Gionata, Schonherr Marek, Winter Jan-Christopher, Yundin Valery (2016), Higgs + Multi-jets in Gluon Fusion, in 12th International Symposium on Radiative Corrections (Radcor 2015) and LoopFest XIV (Radiative Corr, PoS, Sissa, Italy / www.
Les Houches 2015: Physics at TeV Colliders Standard Model Working Group Report
Andersen J. R., Andersen J. R. and others (2016), Les Houches 2015: Physics at TeV Colliders Standard Model Working Group Report, INSPIRE, www.
Measuring the signal strength in ttH with H->bb
Moretti Niccolo, Petrov Petar, Pozzorini Stefano, Spannowsky Michael (2016), Measuring the signal strength in ttH with H->bb, in Phys. Rev., D93(1), 014019-014019.
Multijet merging for vector boson plus jets production including electroweak corrections
Kallweit Stefan, Lindert Jonas, Maierhöfer Philipp, Pozzorini Stefano, Schönherr Marek (2016), Multijet merging for vector boson plus jets production including electroweak corrections, in Loops and Legs in Quantum Field Theory, LL2016, PoS, Sissa, Italy / www.
NLO QCD+EW predictions for V + jets including off-shell vector-boson decays and multijet merging
Kallweit Stefan, Lindert Jonas M., Maierhofer Philipp, Pozzorini Stefano, Schönherr Marek (2016), NLO QCD+EW predictions for V + jets including off-shell vector-boson decays and multijet merging, in JHEP, 04, 021-021.
Phenomenological analysis of Higgs boson production through gluon fusion in association with jets
Greiner Nicolas, Höche Stefan, Luisoni Gionata, Schönherr Marek, Winter Jan-Christopher, Yundin Valery (2016), Phenomenological analysis of Higgs boson production through gluon fusion in association with jets, in JHEP, 01, 169-169.
Physics at a 100 TeV pp collider: Standard Model processes
Mangano M. L., others (2016), Physics at a 100 TeV pp collider: Standard Model processes, CERN report, CERN, Geneva.
Recent developments in Monte-Carlo Event Generators
Schönherr Marek (2016), Recent developments in Monte-Carlo Event Generators, in XLV International Symposium on Multiparticle Dynamics (ISMD 2015), EPJ Web of Conferences, www.
Fast evaluation of theoretical uncertainties with Sherpa and MCgrid
Bothmann Enrico, Schönherr Marek, Schumann Steffen (2015), Fast evaluation of theoretical uncertainties with Sherpa and MCgrid, Proceedings of Science, Sissa, http://pos.sissa.it/cgi-bin/reader/conf.cgi?confid=247.
LHAPDF6: parton density access in the LHC precision era
Buckley Andy, Ferrando James, Lloyd Stephen, Nordström Karl, Page Ben, Rüfenacht Martin, Schönherr Marek, Watt Graeme (2015), LHAPDF6: parton density access in the LHC precision era, in Eur. Phys. J., C75(3), 132-132.
Mass Effects in the Higgs-Gluon Coupling: Boosted vs Off-Shell Production
Buschmann Malte, Goncalves Dorival, Kuttimalai Silvan, Schonherr Marek, Krauss Frank, Plehn Tilman (2015), Mass Effects in the Higgs-Gluon Coupling: Boosted vs Off-Shell Production, in JHEP, 02, 038-038.
Next-to-leading order QCD predictions for top-quark pair production with up to two jets merged with a parton shower
Hoeche Stefan, Krauss Frank, Maierhoefer Philipp, Pozzorini Stefano, Schonherr Marek, Siegert Frank (2015), Next-to-leading order QCD predictions for top-quark pair production with up to two jets merged with a parton shower, in Phys. Lett., B748, 74-78.
NLO electroweak automation and precise predictions for W+multijet production at the LHC
Kallweit Stefan, Lindert Jonas M., Maierhöfer Philipp, Pozzorini Stefano, Schönherr Marek (2015), NLO electroweak automation and precise predictions for W+multijet production at the LHC, in JHEP, 04, 012-012.
NLO QCD+EW automation and precise predictions for V+multijet production
Kallweit Stefan, Lindert Jonas M., Pozzorini Stefano, Schönherr Marek, Maierhöfer Philipp (2015), NLO QCD+EW automation and precise predictions for V+multijet production, in Proceedings, 50th Recontres de Moriond, QCD and high energy interactions : La Thuile, Italy, March 2, ARISF, www.
NLO QCD+EW for V+jets
Schoenherr Marek, Kallweit Stefan, Lindert Jonas M., Pozzorini Stefano, Maierhoefer Philipp, NLO QCD+EW for V+jets, in Fourth Annual Large Hadron Collider Physics LHCP2016, PoS, Sissa, Italy / www.

Collaboration

Group / person Country
Types of collaboration
Zurich University Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Mainz University Germany (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Freiburg University Germany (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Exchange of personnel
DESY Hamburg Germany (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Dresden University Germany (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Standford Linear Accellerator Center United States of America (North America)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Durham University Great Britain and Northern Ireland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Exchange of personnel
CERN Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Universita' Milano Bicocca Italy (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Exchange of personnel

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
Seminar Michigan State University Individual talk Electroweak corrections for LHC physics 01.11.2016 East Lansing, MI, United States of America Schönherr Marek;
9th International Workshop on Top Quark Physics, TOP 2016 Talk given at a conference Electroweak corrections and off-shell effects in tt production and decay 19.09.2016 Olomouc, Czech Republic Pozzorini Stefano;
QCD@LHC Talk given at a conference Sherpa: overview and recent developments 22.08.2016 Zurich, Switzerland Schönherr Marek;
QCD@LHC 2016 Talk given at a conference Theory precision for ttH signals and backgrounds 22.08.2016 Zurich, Switzerland Pozzorini Stefano;
LoopFest XV Talk given at a conference Electroweak corrections to V+jets production 15.08.2016 Buffalo, NY, United States of America Schönherr Marek;
Lectures at African School of Fundamental Physics and Applications Individual talk Monte-Carlo Event Generators: Introduction" (3 lectures & 2 tutorials) 01.08.2016 Kigali, Rwanda Schönherr Marek;
Lecture at 2016 CTEQ & MCnet School Individual talk Electroweak Theory and Higgs Mechanism 06.07.2016 DESY Hamburg, Germany Pozzorini Stefano;
Parton showers and resummation (PSR16) Talk given at a conference Reweighting QCD matrix element and parton shower calculations 04.07.2016 Paris, France Schönherr Marek;
Fourth Annual Large Hadron Collider Physics Conference (LHCP2016) Talk given at a conference NLO electroweak corrections in V+jets 13.06.2016 Lund, Sweden Schönherr Marek;
Mw topical meeting Talk given at a conference Status of electroweak corrections in Sherpa+OpenLoops 08.06.2016 CERN, Geneva, Switzerland Schönherr Marek;
Strategy Workshop on High-Energy Particle Physics in Switzerland Talk given at a conference Theory tools for precision SM and Higgs Physics 07.06.2016 Aegerisee, Switzerland Pozzorini Stefano;
Seminar at Goettingen Universtity Individual talk Electroweak corrections for the LHC 03.06.2016 Goettingen, Germany Schönherr Marek;
KITP Workshop “LHC Run II and the Precision Frontier” Talk given at a conference Precision for V+jets and Dibosons 23.04.2016 KITP, Santa Barbara University of California, United States of America Pozzorini Stefano;
Seminar Milano Bicocca University Individual talk Electroweak corrections for the LHC 14.04.2016 Milano, Italy Schönherr Marek;
Rencontres de Physique de la Vallee d’Aoste Talk given at a conference Recent Theoretical Progress in QCD and EW Corrections 09.03.2016 La Thuile, Italy Pozzorini Stefano;
Meeting of the German Physical Society Talk given at a conference Precision Theory Simulations for the LHC 04.03.2016 Hamburg, Germany Pozzorini Stefano;
Talks at Vienna University Individual talk Scattering Amplitudes and Precision Simulations for the LHC 26.01.2016 Vienna University, Austria Pozzorini Stefano;
The 11th Workshop of the LHC Higgs Cross Section Working Group Talk given at a conference Update of the Les Houches Higgs+jets study using NLO multi-leg approaches and fixed order 13.01.2016 CERN, Geneva, Switzerland Schönherr Marek;
11th Workshop of the LHC Higgs Cross Section Working Group Talk given at a conference ttH/tH working group: status of YR4 preparation and future activities 13.01.2016 CERN, Geneva, Switzerland Pozzorini Stefano;
ATLAS-CMS Monte-Carlo Generators Workshop Talk given at a conference Status and perspectives of loop-induced processes 11.01.2016 CERN. Geneva, Switzerland Schönherr Marek;
Sherpa Users' Day Talk given at a conference Implementation of NLO EW corrections 06.01.2016 TU Dresden, Germany Schönherr Marek;
Sherpa Users' Day Talk given at a conference Systematic uncertainties on-the-fly 06.01.2016 TU Dresden, Germany Schönherr Marek;
Sinergia meeting Talk given at a conference ttH searches in the H->bb channel: precision theory simulations and boosted analyses 17.12.2015 EPFL, Lausanne, Switzerland Moretti Niccolo;
Seminar at DESY Hamburg Individual talk Scattering Amplitudes and Precision Simulations for the LHC 02.12.2015 DESY Hamburg, Germany Pozzorini Stefano;
Higgs Couplings 2015 Talk given at a conference MC for ttH and SM backgrounds 13.10.2015 Lumley Castle, Durham, Great Britain and Northern Ireland Pozzorini Stefano;
International Symposium on Multiparticle Dynamics Talk given at a conference Recent Developments in Monte Carlo Event Generators 04.10.2015 Wildbad Kreuth, Germany Schönherr Marek;
International Symposium on Multiparticle Dynamics Talk given at a conference Recent developments in Monte-Carlo Event Generators 04.10.2015 Wildbad Kreuth, Germany Schönherr Marek;
ATLAS Physics Modeling Group meeting Individual talk On-the-fly scale variations in Sherpa 22.09.2015 CERN, Geneva, Switzerland Schönherr Marek;
3rd Conference on Large Hadron Collider Physics (LHCP 2015) Talk given at a conference Electroweak theory at the LHC 31.08.2015 St.Petersburgh, Russia Pozzorini Stefano;
Sherpa Tutorial Talk given at a conference Sherpa-2.2.1: overview, developments and usage 29.08.2015 CERN, Geneva, Switzerland Schönherr Marek;
Les Houches Workshop "Physics at TeV Colliders" Talk given at a conference Les Houches 2015 Monte Carlo working group 01.06.2015 Les Houches, France Schönherr Marek;
Theory Seminar at Universita degli Studi di Milano Individual talk Scattering Amplitudes and (N)NLO simulations with OpenLoops 21.05.2015 Milano, Italy Pozzorini Stefano;
Theory Seminar at LPTHE, Paris VI University Individual talk Scattering Amplitudes and (N)NLO simulations with OpenLoops 04.05.2015 Paris, France Pozzorini Stefano;
Standard Model at LHC 2015 Talk given at a conference Precise electroweak predictions for V+multijet production 21.04.2015 Florence, Italy Pozzorini Stefano;
9th Workshop of LHC Higgs Cross Section Working Group Talk given at a conference ttH Theory Overview 22.01.2015 CERN, Geneva, Switzerland Pozzorini Stefano;
Higgs (N)NLO Monte Carlo Tools Workshop for LHC RUN-2 Talk given at a conference tt+jets (incl HF), ttV+jets in SHERPA+OPENLOOPS 17.12.2014 CERN, Geneva, Switzerland Pozzorini Stefano;
Higgs+Jets Workshop Durham Talk given at a conference Higgs production at NLO in Sherpa 08.12.2014 Durham, Great Britain and Northern Ireland Schönherr Marek;
Institutsseminar Universitaet Freiburg Individual talk Electroweak Corrections for LHC physics 18.11.2014 Freiburg, Germany Schönherr Marek;
TOP 2014 - 7th International Workshop on Top-quark Physics Talk given at a conference New generators (including future developments on EW correction to top) for the HL-­LHC 02.10.2014 Cannes, France Pozzorini Stefano;


Self-organised

Title Date Place

Awards

Title Year
SNF consolidator grant 2015

Associated projects

Number Title Start Funding scheme
157722 Quantum Precision for the high energy phase of the Large Hadron Collider 01.10.2015 SNSF Consolidator Grants
141847 Particle Physics with high-quality data from the CERN LHC 01.10.2012 Sinergia
128552 QCD quantum corrections at the Large Hadron Collider 01.10.2010 SNSF Professorships
160814 Particle Physics with high-quality data from the CERN LHC 01.10.2015 Sinergia

Abstract

After the recent discovery of the Higgs Boson, future measurements at the Large Hadron Collider (LHC) will be aimed at testing the symmetry breaking mechanism, by which elementary particles acquire their mass, and searching for new phenomena beyond the Standard Model. Many measurements and searches will be limited by systematic uncertainties, and the precision of theoretical simulations will play an increasingly important role in order to fully exploit the possibility to use LHC data for stringent tests of the Standard Model and alternative theories.In this context, precise simulations of multi-particle processes will become increasingly important in the high-energy and high-luminosity phase of the LHC experiment. Thanks to a novel algorithmic concept, which was proposed in the first phase of this project and implemented in the OpenLoops program, such multi-particle simulations can now be performed with an unprecedented degree of efficency and automation. The OpenLoops program and its automated interface with the Sherpa Monte-Carlo generator allow one to obtain theoretical predictions for any Standard-Model process with up to (atleast) six external particles at next-to-leading order (NLO) in the strong coupling constant.This proposal aims at promoting Sherpa+OpenLoops to the most complete tool for precision simulations in the LHC era. To this end the functionality of OpenLoops and Sherpa will be extended in various new directions: (i) in view of the importance of electroweak corrections for the high-energy run of the LHC, the NLO automation will be extended to electroweak one-loop contributions and to their photon-emission counterpart. Electroweak NLO corrections will be supplemented by higher-order Sudakov logarithms and matched to a QED parton shower. (ii) We will develop a fully automated mechanism to describe electroweak and QCD NLO effects in chain decays, including consistent matching to the parton shower in the various production and decay stages of scattering processes. (iii) We will develop and automated framework for the consistent combination of fixed-order NNLO calculations and merged NLO simulations with multiple final-state jets. (iv) These new automated techniques will be applied to key processes of the LHC physics program, like tt+jets, W/Z+jets, di-photon and di-boson production. (v) A specific subproject is devoted to precise theory simulations for the ttH analyses, with emphasis to the dominant H->bb decay channel, where theory uncertainties in the background simulation represent amajor obstacle to the observation of this associated Higgs-boson production mode.
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