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Portrait of RP

Ruth Pöttgen

Senior Lecturer

Portrait of RP

Search for flavour-changing neutral current top-quark decays t → qZ in proton-proton collisions at √s=13 TeV with the ATLAS detector

Author

  • M Aaboud
  • 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
  • L Zwalinski

Summary, in English

A search for flavour-changing neutral-current processes in top-quark decays is presented. Data collected with the ATLAS detector from proton-proton collisions at the Large Hadron Collider at a centre-of-mass energy of s=13 TeV, corresponding to an integrated luminosity of 36.1 fb−1, are analysed. The search is performed using top-quark pair events, with one top quark decaying through the t → qZ (q = u, c) flavour-changing neutral-current channel, and the other through the dominant Standard Model mode t → bW. Only Z boson decays into charged leptons and leptonic W boson decays are considered as signal. Consequently, the final-state topology is characterized by the presence of three isolated charged leptons (electrons or muons), at least two jets, one of the jets originating from a b-quark, and missing transverse momentum from the undetected neutrino. The data are consistent with Standard Model background contributions, and at 95% confidence level the search sets observed (expected) upper limits of 1.7 × 10−4 (2.4 × 10−4) on the t → uZ branching ratio and 2.4 × 10−4 (3.2 × 10−4) on the t → cZ branching ratio, constituting the most stringent limits to date.[Figure not available: see fulltext.]. © 2018, The Author(s).

Department/s

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

Publishing year

2018

Language

English

Publication/Series

Journal of High Energy Physics

Volume

2018

Issue

7

Document type

Journal article

Publisher

Springer

Topic

  • Subatomic Physics

Keywords

  • Hadron-Hadron scattering (experiments)

Status

Published

ISBN/ISSN/Other

  • ISSN: 1029-8479