Project

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Mixed QCD and electroweak corrections for Higgs production at the LHC

Applicant Anastasiou Charalampos
Number 165772
Funding scheme Project funding (Div. I-III)
Research institution Institut für Theoretische Physik ETH Zürich
Institution of higher education ETH Zurich - ETHZ
Main discipline Theoretical Physics
Start/End 01.04.2016 - 31.03.2018
Approved amount 319'538.00
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All Disciplines (2)

Discipline
Theoretical Physics
Particle Physics

Keywords (4)

Perturbative Calculations; Quantum Chromodynamics; Theory of Elementary Particles; Higgs boson physics

Lay Summary (Italian)

Lead
Dopo la scoperta del bosone di Higgs , gli esperimenti di LHC misurano il ritmo di produzione di particelle di Higgs con alta precisione. Questo ritmo è previsto nel Modello Standard della fisica delle particelle con un'incertezza più grande. Per abbinare la precisione sperimentale, fenomeni fisici sottili devono essere prese in considerazione .
Lay summary
In questo progetto, ci proponiamo di calcolare l'effetto 
delle interazioni simultanee del bosone di Higgs e QCD
( quark o gluoni ) ed elettrodeboli ( bosoni W o Z) particelle.
Questo richiede il calcolo dei diagrammi di Feynman complicate , che sono alla frontiera
di ciò che è attualmente possibile . Con il nostro lavoro, potremo migliorare i metodi
matematici generali che sono disponibili per il calcolo dei diagrammi di Feynman.
Questa parte del progetto sarà utile per molte altre applicazioni in calcoli perturbativi
in Teoria Quantistica dei Campi .

Al completamento del progetto, avremo eliminato uno dei maggiori incertezze teoriche
rimanente per una determinazione precisa del ritmo di produzione del bosone di Higgs a LHC .
Direct link to Lay Summary Last update: 31.03.2016

Lay Summary (English)

Lead
After the discovery of the Higgs boson, the LHC experiments are inferring from their increasingly precise measurements the produced number of Higgs boson particles. The ultimate experimental precision on this number will be of a few percent. This number is predicted in the Standard Model of particle physics with a larger uncertainty. To match the experimental uncertainty, many subtle physical phenomena need to be taken into account.
Lay summary

In this project, we aim to compute the effect of simultaneous interactions of the Higgs boson and QCD (quark or gluons) and electroweak (W or Z bosons) particles.  This requires the computation of  complicated three-loop Feynman diagrams, which are at the frontier of what is presently possible.  We will improve on known mathematical methods for the computation of Feynman diagrams in order to elevate them to the complication level of our problem. This part of our project will be useful for many other applications in general perturbative computations in Quantum Field Theory. Upon completion of our project, we will have removed one of the major remaining  theoretical uncertainties for a precise determination of the production rate of the Higgs boson at the LHC.    

Direct link to Lay Summary Last update: 31.03.2016

Responsible applicant and co-applicants

Employees

Publications

Publication
Mixed QCD-electroweak corrections to Higgs production via gluon fusion in the small mass approximation
Anastasiou Charalampos, Del Duca Vittorio, Furlan Elisabetta, Mistlberger Bernhard, Moriello Francesco, Schweitzer Armin, Specchia Caterina (2019), Mixed QCD-electroweak corrections to Higgs production via gluon fusion in the small mass approximation, in Journal of High Energy Physics, 2019(3), 162-162.

Collaboration

Group / person Country
Types of collaboration
Dr Claude Duhr/ CERN theory Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Dr Bernhard Mistlberger/ CERN Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Dr Falko Dulat/ SLAC United States of America (North America)
- in-depth/constructive exchanges on approaches, methods or results
- Publication

Abstract

The Large Hadron Collider has entered a new phase of precision measurements with emphasis on the properties of the newly discovered Higgs boson. This research program will refer frequently to the theoretical predictions for the total number of Higgs bosons which are produced at the LHC (the inclusive cross-section). The cross-section for the production of the Higgs boson via the gluon-fusion mechanism is known through next-to-next-to-next-to-leading-order (N3LO) in the strong coupling perturbative QCD expansion. Electroweak corrections are known exactly only at next-to-leading-order. Currently, mixed QCD and electroweak corrections (mixed QCD/EWK) are estimated to be as important as the N3LO QCD corrections. However, these mixed QCD/EWK corrections can only be estimated by means of an effective field theory, which is however not valid for realistic W-boson and the Higgs-boson mass values. The aim of the project is to perform a realistic computation of mixed QCD/EWK corrections at three loops. This will eliminate a source of theoretical uncertainty for the inclusive Higgs cross-section which iscurrently dominant and it will improve the precision of themeasurements of Higgs couplings at the LHC. The proposed research will have a strong mathematical component in developing methods for multiloop amplitudes. It will therefore lead to further progress in the field ofperturbative QCD beyond the strict boundaries of the phenomenological goal of the project.
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