Measurement of the inclusive and fiducial tt¯ production cross-sections in the lepton+jets channel in pp collisions at √s=8TeV with the ATLAS detector

Research output: Contribution to journalArticlepeer-review

Authors

  • ATLAS Collaboration

Colleges, School and Institutes

External organisations

  • University Politehnica Bucharest
  • Faculdade de Ciencias e Tecnologia, New University of Lisbon
  • Centre National de l’Energie des Sciences Techniques Nucleaires
  • European Organization for Nuclear Research (CERN)
  • Université Mohamed Premier and LPTPM
  • CNRS/IN2P3
  • School of Life Sciences, Arizona State University, Tempe, AZ, 85287, USA; Department of Chemistry and Biochemistry, The University of Oklahoma, Norman, OK, 73019, USA.
  • Institute of Physics Azerbaijan National Academy of Sciences
  • IN2P3
  • University of Toronto
  • Santa Cruz Institute for Particle Physics
  • SUSSEX UNIVERSITY
  • 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
  • Tokyo Metropolitan University
  • Electronics and Telecommunications
  • Northern Illinois University
  • University of Munich
  • RUTHERFORD APPLETON LABORATORY
  • University of Belgrade
  • Alexandru Ioan Cuza University of Iasi

Abstract

The inclusive and fiducial tt¯ production cross-sections are measured in the lepton+jets channel using 20.2fb-1 of proton–proton collision data at a centre-of-mass energy of 8 TeV recorded with the ATLAS detector at the LHC. Major systematic uncertainties due to the modelling of the jet energy scale and b-tagging efficiency are constrained by separating selected events into three disjoint regions. In order to reduce systematic uncertainties in the most important background, the W+\,jets process is modelled using Z+ jets events in a data-driven approach. The inclusive tt¯ cross-section is measured with a precision of 5.7% to be σinc(tt¯)=248.3±0.7(stat.)±13.4(syst.)±4.7(lumi.)pb, assuming a top-quark mass of 172.5 GeV. The result is in agreement with the Standard Model prediction. The cross-section is also measured in a phase space close to that of the selected data. The fiducial cross-section is σfid(tt¯)=48.8±0.1(stat.)±2.0(syst.)±0.9(lumi.)pb with a precision of 4.5%.

Details

Original languageEnglish
Article number487
JournalEuropean Physical Journal C
Volume78
Issue number6
Early online date12 Jun 2018
Publication statusE-pub ahead of print - 12 Jun 2018