The differential cross-section for pair production of top quarks with high transverse momentum is measured in $20.3{\mathrm{fb}}^{-1}$ of proton-proton collisions at a center-of-mass energy of 8 TeV. The measurement is performed for $t\overline{t}$ events in the $\mathrm{lepton}+\mathrm{jets}$ channel. The cross-section is reported as a function of the hadronically decaying top quark transverse momentum for values above 300 GeV. The hadronically decaying top quark is reconstructed as an anti-$k_t$ jet with radius parameter $R=1.0$ and identified with jet substructure techniques. The observed yield is corrected for detector effects to obtain a cross-section at particle level in a fiducial region close to the event selection. A parton-level cross-section extrapolated to the full phase space is also reported for top quarks with transverse momentum above 300 GeV. The predictions of a majority of next-to-leading-order and leading-order matrix-element Monte Carlo generators are found to agree with the measured cross-sections.

• Received 14 October 2015

DOI:https://doi.org/10.1103/PhysRevD.93.032009

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© 2016 CERN, for the ATLAS Collaboration