Francesco Spano(Royal Holloway, University of London (GB))
Description
A review will be provided for the measurement of the differential cross-section for boosted top quark pair production using 20.3 fb−1 of proton-proton collisions at a center-of-mass energy of 8 TeV. The measurement is performed for tt ̄ events in the lepton+jets channel, where the hadronically decaying top quark has a transverse momentum above 300 GeV. Jet substructure techniques are employed to identify top quarks, which are reconstructed with an anti-kt jet with radius parameter R = 1.0. The cross-section is reported as a function of the hadronically decaying top quark transverse momentum. 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 next-to-leading-order and leading-order matrix element plus parton shower Monte Carlo generators are found to generally overestimate the measured cross-sections.
