Measurement of the top-quark pole mass in dileptonic tt¯ + 1-jet events at s=13 TeV with the ATLAS experiment


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

Journal of High Energy Physics, vol.2025, no.12, 2025 (SCI-Expanded, Scopus) identifier identifier

  • Publication Type: Article / Article
  • Volume: 2025 Issue: 12
  • Publication Date: 2025
  • Doi Number: 10.1007/jhep12(2025)023
  • Journal Name: Journal of High Energy Physics
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, INSPEC, MathSciNet, zbMATH, Directory of Open Access Journals, Nature Index
  • Keywords: Hadron-Hadron Scattering, Top Physics
  • Ankara University Affiliated: Yes

Abstract

A measurement of the top-quark pole mass mtpole is presented in tt¯ events with an additional jet, tt¯ + 1-jet, produced in pp collisions at s=13 TeV. The data sample, recorded with the ATLAS experiment during Run 2 of the LHC, corresponds to an integrated luminosity of 140 fb−1. Events with one electron and one muon of opposite electric charge in the final state are selected to measure the tt¯ + 1-jet differential cross-section as a function of the inverse of the invariant mass of the tt¯ + 1-jet system. Iterative Bayesian Unfolding is used to correct the data to enable comparison with fixed-order calculations at next-to-leading-order accuracy in the strong coupling. The process pp→tt¯j2→3, where top quarks are taken as stable particles, and the process pp→bb¯l+νl−ν¯j2→7, which includes top-quark decays to the dilepton final state and off-shell effects, are considered. The top-quark mass is extracted using a χ2 fit of the unfolded normalized differential cross-section distribution. The results obtained with the 2 → 3 and 2 → 7 calculations are compatible within theoretical uncertainties, providing an important consistency check. The more precise determination is obtained for the 2 → 3 measurement: mtpole=170.7±0.3stat.±1.4syst.±0.3scale±0.2PDF⊕αS GeV, which is in good agreement with other top-quark mass results.