Search for direct top squark pair production in events with a Higgs or Z boson, and missing transverse momentum in √s=13 TeV pp collisions with the ATLAS detector

Research output: Contribution to journalArticlepeer-review

Authors

  • ATLAS Collaboration

Colleges, School and Institutes

External organisations

  • Université Mohamed Premier and LPTPM
  • IN2P3
  • University of Oklahoma
  • Azerbaijan National Academy of Sciences
  • University of Toronto
  • Santa Cruz Institute for Particle Physics
  • University of Sussex
  • Tel Aviv University
  • Technion - Israel Institute of Technology
  • University of Oregon
  • Stockholm University
  • The Oskar Klein Centre
  • Department of Physics and Astronomy and INFN
  • Abdus Salam International Centre for Theoretical Physics
  • King's College London
  • Tokyo Metropolitan University
  • Electronics and Telecommunications
  • Northern Illinois University
  • University of Munich
  • Rutherford Appleton Laboratory
  • University of Belgrade
  • Alexandru Ioan Cuza University of Iasi
  • Laboratório de Instrumentação e Física Experimental de Partículas
  • University of Granada

Abstract

A search for direct top squark pair production resulting in events with either a same-flavour opposite-sign dilepton pair with invariant mass compatible with a Z boson or a pair of jets compatible with a Standard Model (SM) Higgs boson (h) is presented. Requirements on the missing transverse momentum, together with additional selections on leptons, jets, jets identified as originating from b-quarks are imposed to target the other decay products of the top squark pair. The analysis is performed using proton-proton collision data at s=13 TeV collected with the ATLAS detector at the LHC in 2015–2016, corresponding to an integrated luminosity of 36.1 fb−1. No excess is observed in the data with respect to the SM predictions. The results are interpreted in two sets of models. In the first set, direct production of pairs of lighter top squarks (t˜ 1) with long decay chains involving Z or Higgs bosons is considered. The second set includes direct pair production of the heavier top squark pairs (t˜ 2) decaying via t˜ 2→ Zt˜ 1 or t˜ 2→ ht˜ 1. The results exclude at 95% confidence level t˜ 2 and t˜ 1 masses up to about 800 GeV, extending the exclusion region of supersymmetric parameter space covered by previous LHC searches.[Figure not available: see fulltext.].

Bibliographic note

29 pages plus author list + cover pages (46 pages total), 7 figures, 9 tables, submitted to JHEP, All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/SUSY-2016-20/

Details

Original languageEnglish
Article number6
JournalJournal of High Energy Physics
Volume2017
Issue number8
Publication statusPublished - 1 Aug 2017

Keywords

  • Beyond Standard Model, Hadron-Hadron scattering (experiments), Higgs physics

ASJC Scopus subject areas