Observation of tt¯ production in the lepton+jets and dilepton channels in p+Pb collisions at sNN = 8.16 TeV with the ATLAS detector


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Aad G., Aakvaag E., Abbott B., Abdelhameed S., Abeling K., Abicht N., ...More

Journal of High Energy Physics, vol.2024, no.11, 2024 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 2024 Issue: 11
  • Publication Date: 2024
  • Doi Number: 10.1007/jhep11(2024)101
  • Journal Name: Journal of High Energy Physics
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, INSPEC, zbMATH, Directory of Open Access Journals, Nature Index
  • Keywords: Heavy Ion Experiments, Top Physics
  • Open Archive Collection: AVESIS Open Access Collection
  • Istanbul University Affiliated: Yes

Abstract

This paper reports the observation of top-quark pair production in proton-lead collisions in the ATLAS experiment at the Large Hadron Collider. The measurement is performed using 165 nb−1 of p+Pb data collected at sNN = 8.16 TeV in 2016. Events are categorised in two analysis channels, consisting of either events with exactly one lepton (electron or muon) and at least four jets, or events with two opposite-charge leptons and at least two jets. In both channels at least one b-tagged jet is also required. Top-quark pair production is observed with a significance over five standard deviations in each channel. The top-quark pair production cross-section is measured to be σtt¯=58.1±2.0stat.−4.4+4.8syst. nb, with a total uncertainty of 9%. In addition, the nuclear modification factor is measured to be RpA=1.090±0.039stat.−0.087+0.094syst. The measurements are found to be in good agreement with theory predictions involving nuclear parton distribution functions.