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Oxana Smirnova

Oxana Smirnova

Senior Lecturer, Deputy Head of division

Oxana Smirnova

Evidence for the associated production of the Higgs boson and a top quark pair with the ATLAS detector

Author

  • M Aaboud
  • G Aad
  • B. Abbott
  • O Abdinov
  • B Abeloos
  • S. H. Abidi
  • Torsten Åkesson
  • Simona Bocchetta
  • Eric Corrigan
  • Caterina Doglioni
  • Eva Brottmann Hansen
  • Vincent Hedberg
  • Göran Jarlskog
  • Charles Kalderon
  • Edgar Kellermann
  • Balazs Konya
  • Else Lytken
  • Katja Mankinen
  • Ulf Mjörnmark
  • Ruth Pöttgen
  • Trine Poulsen
  • Oxana Smirnova
  • Oleksandr Viazlo

Summary, in English

A search for the associated production of the Higgs boson with a top quark pair (ttH) is reported. The search is performed in multilepton final states using a data set corresponding to an integrated luminosity of 36.1 fb-1 of proton-proton collision data recorded by the ATLAS experiment at a center-of-mass energy s=13 TeV at the Large Hadron Collider. Higgs boson decays to WW∗, ττ, and ZZ∗ are targeted. Seven final states, categorized by the number and flavor of charged-lepton candidates, are examined for the presence of the Standard Model Higgs boson with a mass of 125 GeV and a pair of top quarks. An excess of events over the expected background from Standard Model processes is found with an observed significance of 4.1 standard deviations, compared to an expectation of 2.8 standard deviations. The best fit for the ttH production cross section is σ(ttH)=790-210+230 fb, in agreement with the Standard Model prediction of 507-50+35 fb. The combination of this result with other ttH searches from the ATLAS experiment using the Higgs boson decay modes to bb, γγ and ZZ∗→4, has an observed significance of 4.2 standard deviations, compared to an expectation of 3.8 standard deviations. This provides evidence for the ttH production mode. © 2018 CERN, for the ATLAS Collaboration. Published by the American Physical Society under the terms of the »https://creativecommons.org/licenses/by/4.0/» Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3.

Department/s

  • Particle and nuclear physics
  • eSSENCE: The e-Science Collaboration

Publishing year

2018

Language

English

Publication/Series

Physical Review D

Volume

97

Issue

7

Document type

Journal article

Publisher

American Physical Society

Topic

  • Subatomic Physics

Status

Published

ISBN/ISSN/Other

  • ISSN: 2470-0010