Physics potential for boosted topologies in top-quark pair production at a multi-TeV Compact Linear Collider
The physics potential for boosted topologies in top-quark pair production is studied at centre-of-mass energies of 1.4 TeV and 3 TeV at the proposed high-luminosity linear electron-positron Compact Linear Collider (CLIC). The analyses presented in this paper focus on "single lepton+jets" ttbar final states and apply jet sub-structure techniques to explore the highly collimated jet environment above 1 TeV. The charged lepton is used to determine the charge of both top quarks. We present results for the ttbar production cross section and the forward-backward asymmetry in the kinematic region where the effective collision energy is above 1.2 TeV (2.6 TeV) for operation at 1.4 TeV (3 TeV), taking into account the CLIC luminosity spectrum and initial-state radiation. The results are based on detailed Monte Carlo simulation studies with a GEANT4 based simulation of the CLIC_ILD detector concept and particle-flow based event reconstruction. All data samples considered include beam-induced backgrounds and other relevant background processes. The expected precision on the ttbar production cross section and the forward-backward asymmetry are 1.1% (2.0%) and 1.4% (2.3%), respectively, for operation at 1.4 TeV (3 TeV) with an integrated luminosity of 2.0 inverse attobarn (4.0 inverse attobarn) and with -80% electron polarisation. For improved Beyond Standard Model reach, operation is also foreseen at +80% electron polarisation, with an integrated luminosity of 0.5 inverse attobarn (1.0 inverse attobarn) at 1.4 TeV (3 TeV), where the corresponding numbers are about a factor 2.5 higher.