TY - JOUR
T1 - Differential tt̅ cross-section measurements using boosted top quarks in the all-hadronic final state with 139 fb−1 of ATLAS data
AU - ATLAS Collaboration
AU - Allport, Phil
AU - Bellos, Panagiotis
AU - Bird, Gareth
AU - Bracinik, Juraj
AU - Charlton, David
AU - Chisholm, Andrew
AU - Fitschen, Tobias
AU - Freeman, Patrick
AU - George, William
AU - Gonella, Laura
AU - Hawkes, Chris
AU - Kempster, Jacob
AU - Mendes Jacques Da Costa, Antonio Manuel
AU - Neep, Thomas
AU - Newman, Paul
AU - Nikolopoulos, Konstantinos
AU - Cardoso Silva, Júlia
AU - Stampekis, Alexis
AU - Thomas, Jurgen
AU - Thompson, Paul
AU - Virdee, Gov
AU - Ward, Robert
AU - Watson, Alan
AU - Watson, Miriam
PY - 2023/4/18
Y1 - 2023/4/18
N2 - 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 tt̅→WWbb̅ 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.
AB - 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 tt̅→WWbb̅ 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.
KW - Hadron-Hadron Scattering
KW - Jet Substructure and Boosted Jets
KW - Top Physics
U2 - 10.1007/JHEP04(2023)080
DO - 10.1007/JHEP04(2023)080
M3 - Article
SN - 1126-6708
VL - 2023
JO - JHEP
JF - JHEP
IS - 4
M1 - 80
ER -