Top quark mass measurement and color effects at the LHC

The top quark, the heaviest fundamental particle discovered to date, is one of the most peculiar particles that were discovered so far. It plays a crucial role in consistency checks of the Standard Model and in searches for new physics, e.g., supersymmetry, composite Higgs, and many other exotic models. In this thesis, an important property of the top quark is measured: the mass. This analysis is based on the data recorded at a center-of-mass energy of 13 TeV in 2016 with the CMS detector at the CERN LHC, and corresponds to an integrated luminosity of 35.9 fb$^{-1}$. The mass of the top quark is measured using the top quark pair event candidate, which corresponds to events with one muon or electron and at least four jets. The corresponding decay products are used in a kinematic fit to perform the jet quark assignment, increase the fraction of correctly reconstructed top quarks and to improve the mass resolution. Using the ideogram method the top quark mass is measured simultaneously with the jet scale factor (JSF), constrained by the jets arising from the W boson decay. The estimated result is calibrated with samples simulated with a next-to-leading order matrix element generator matched to the parton shower. The top quark mass is measured to be $m_{t} = 172.25 \pm0.08 \mbox{ (stat+JSF)}\pm0.62\mbox{ (syst) GeV}$. The results are tested for possible kinematic dependence by performing measurements of the top quark mass in different phase space regions.The residual data-to-simulation calibration of the energy of the jets is also estimated from dijet events with data collected at center-of-mass energy of 13 TeV in 2015 with the CMS detector corresponding to an integrated luminosity of 2.1 fb$^{-1}$. The corrections are performed using selected back-to-back dijet events by the MPF and dijet balance methods and are found to differ from unity by less then 3 % in the barrel region and up to 17 % in the endcap and forward regions of the detector. This result was used in the top mass measurement.Additionally, a tune for a possible color reconnection between the different multiple parton interaction systems is performed for the recently available QCD-inspired model. The predictions obtained by this tune are able to describe underlying event observables as well as measured charged particle multiplicities. The results are used for a more reliable estimation of the corresponding systematic uncertainty.