The browser you are using is not supported by this website. All versions of Internet Explorer are no longer supported, either by us or Microsoft (read more here: https://www.microsoft.com/en-us/microsoft-365/windows/end-of-ie-support).

Please use a modern browser to fully experience our website, such as the newest versions of Edge, Chrome, Firefox or Safari etc.

Default user image.

Alexander Ekman

Doctoral student

Default user image.

Search for tt¯ H/ A→ tt¯ tt¯ production in the multilepton final state in proton–proton collisions at √s = 13 TeV with the ATLAS detector

Author

  • G. Aad
  • T.P.A. Åkesson
  • E.E. Corrigan
  • C. Doglioni
  • P.A. Ekman
  • J. Geisen
  • V. Hedberg
  • G. Jarlskog
  • B. Konya
  • E. Lytken
  • K.H. Mankinen
  • C. Marcon
  • J.U. Mjörnmark
  • G.A. Mullier
  • R. Poettgen
  • N.D. Simpson
  • E. Skorda
  • O. Smirnova
  • L. Zwalinski
Show all

Summary, in English

A search for a new heavy scalar or pseudo-scalar Higgs boson (H/A) produced in association with a pair of top quarks, with the Higgs boson decaying into a pair of top quarks (H/A → tt¯) is reported. The search targets a final state with exactly two leptons with same-sign electric charges or at least three leptons. The analysed dataset corresponds to an integrated luminosity of 139 fb −1 of proton–proton collisions collected at a centre-of-mass energy of 13 TeV with the ATLAS detector at the LHC. Two multivariate classifiers are used to separate the signal from the background. No significant excess of events over the Standard Model expectation is observed. The results are interpreted in the context of a type-II two-Higgs-doublet model. The observed (expected) upper limits at 95% confidence level on the tt¯ H/ A production cross-section times the branching ratio of H/A → tt¯ range between 14 (10) fb and 6 (5) fb for a heavy Higgs boson with mass between 400 GeV and 1000 GeV, respectively. Assuming that only one particle, either the scalar H or the pseudo-scalar A, contributes to the tt¯ tt¯ final state, values of tan β below 1.2 or 0.5 are excluded for a mass of 400 GeV or 1000 GeV, respectively. These exclusion ranges increase to tan β below 1.6 or 0.6 when both particles are considered. [Figure not available: see fulltext.] © 2023, The Author(s).

Department/s

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

Publishing year

2023

Language

English

Publication/Series

Journal of High Energy Physics

Volume

2023

Issue

7

Document type

Journal article

Publisher

Springer

Topic

  • Subatomic Physics

Keywords

  • Beyond Standard Model
  • Hadron-Hadron Scattering
  • Top Physics

Status

Published

ISBN/ISSN/Other

  • ISSN: 1029-8479