Differential t¯t cross-section measurements using boosted top quarks in the all-hadronic final state with 139 fb−1 of ATLAS data

ATLAS Publications, T.M. Carter, A. Hasib, M.P. Heath, S. Palazzo, V.A. Parrish, E.P. Takeva, N. Themistokleous, E.M. Villhauer, E. Zaid

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

Measurements of single-, double-, and triple-differential cross-sections are presented for boosted top-quark pair-production in 13 TeV proton–proton collisions recorded by the ATLAS detector at the LHC. The top quarks are observed through their hadronic decay and reconstructed as large-radius jets with the leading jet having transverse momentum (pT) greater than 500 GeV. The observed data are unfolded to remove detector effects. The particle-level cross-section, multiplied by the t¯t → W W b¯b branching fraction and measured in a fiducial phase space defined by requiring the leading and second-leading
jets to have pT > 500 GeV and pT > 350 GeV, respectively, is 331 ± 3(stat.) ± 39(syst.) fb. This is approximately 20% lower than the prediction of 398+48
−49 fb by Powheg+Pythia 8 with next-to-leading-order (NLO) accuracy but consistent within the theoretical uncertainties. Results are also presented at the parton level, where the effects of top-quark decay, parton showering, and hadronization are removed such that they can be compared with fixed-order next-to-next-to-leading-order (NNLO) calculations. The parton-level cross-section, measured in a fiducial phase space similar to that at particle level, is
1.94 ± 0.02(stat.) ± 0.25(syst.) pb. This agrees with the NNLO prediction of 1.96+0.02−0.17 pb. Reasonable agreement with the differential cross-sections is found for most NLO models, while the NNLO calculations are generally in better agreement with the data. The differential cross-sections are interpreted using a Standard Model effective field-theory formalism and limits are set on Wilson coefficients of several four-fermion operators.
Original languageEnglish
Article number80
Pages (from-to)1-106
Number of pages106
Journal Journal of High Energy Physics
Volume2023
Issue number4
DOIs
Publication statusPublished - 18 Apr 2023

Keywords / Materials (for Non-textual outputs)

  • Hadron-Hadron Scattering
  • Jet Substructure and Boosted Jets
  • Top Physics

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