Study of single boosted top-quark production at the CMS experiment

In this master's thesis, a first feasibility study for the measurement of single top-quark production in the highly Lorentz-boosted kinematic regime is presented. The analyzed data set corresponds to an integrated luminosity of 35.9 $\mathrm{fb}^{-1}$ and was recorded by the CMS detector at the CERN Large Hadron Collider in the year 2016, using proton-proton collisions at a center-of-mass energy of 13 TeV.
Differential cross sections of single top-quark production in association with a W boson are measured as function of the transverse momentum of the top quark in an interval ranging from 200 GeV up to 1.2 TeV, using the electron+jets and muon+jets final states, presuming that the top quark decays hadronically. Due to the boosted final-state topology, the top quark is reconstructed as one large jet.
A multivariate method is used to discriminate between the signal process and the dominant background, top-quark pair production. In each bin of the transverse momentum of the top-jet candidate, the simulated model is fitted to data according to a maximum-likelihood estimate, utilizing the response distributions of boosted decision trees. In order to extract cross sections on parton level, a simplified bin-by-bin unfolding procedure is employed.