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Investigation of top quarks with high transverse momentum at the ATLAS experiment
Palatková, Sára ; Berta, Peter (advisor) ; Federič, Pavol (referee)
The main focus of this work is on the investigation of top quarks with high transverse momentum at the ATLAS experiment. In the first chapter we describe the Standard Model of Particle Physics and its components. In the second chapter we deal with top quark as the heaviest elementary particle in more detail and the end of the chapter is dedicated to top quarks with high transverse momentum and their identification. In chapter three we present kinematic variables used in hadron collisions and we describe the ATLAS detector on the LHC accelerator. The practical part of the work deals with top quarks with high transverse momentum. We investigate simulated data for the physical process of four top quarks production in a proton-proton collision at the center of mass energy of 13 TeV. Finally, an algorithm which identifies top quarks with high transverse momentum is designed and verified. 1
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Investigation of properties of the top quark with the ATLAS experiment at LHC
Berta, Peter ; Leitner, Rupert (advisor) ; Bielčíková, Jana (referee) ; Kepka, Oldřich (referee)
This thesis presents the measurement of the differential cross section of the top-antitop pair production in proton-proton collisions at center-of-mass energy of 8 TeV at the ATLAS experiment. The measurement is performed for top-antitop events in the single lepton decay channel in the boosted topol- ogy. The measured differential cross section is expressed as a function of the top quark transverse momentum at particle level and at parton level. The mea- sured distributions are compatible with the theoretical predictions of the Standard Model. The experimental techniques used in this measurement are discussed with emphasis on the jet reconstruction and on the identification of jets originating from b-quark fragmentation. The jet reconstruction is influenced by simultane- ous proton-proton collisions (pileup), and the mitigation of these pileup effects is studied. A novel pileup subtraction technique for jets is proposed using an ex- tension of the methods currently being employed by the LHC experiments. The new method has a good performance in removing the pileup contributions at the level of jet constituents. 1
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Studium kinematiky rozpadů top-antitopových párů v experimentu Atlas
Berta, Peter ; Kvita, Jiří (advisor) ; Soustružník, Karel (referee)
In this thesis, I deal with the measurement of the transverse momentum spectrum of the top quark produced in top-antitop pairs at the LHC at center of mass energy 7 TeV. The analysis is carried out within the ATLAS collaboration. In the single lepton decay channel, I have performed studies on the simulation which were necessary to obtain the final spectrum from real data. I describe basic event selection rules to reduce background events. I study the efficiency of top-antitop pairs reconstruction. I study the unfolding of the measured spectrum which corrects for effects caused by imperfect resolutions. At the end, I show the measured top quark transverse momentum spectrum obtained from my analysis.
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Investigation of properties of the top quark with the ATLAS experiment at LHC
Berta, Peter ; Leitner, Rupert (advisor) ; Bielčíková, Jana (referee) ; Kepka, Oldřich (referee)
This thesis presents the measurement of the differential cross section of the top-antitop pair production in proton-proton collisions at center-of-mass energy of 8 TeV at the ATLAS experiment. The measurement is performed for top-antitop events in the single lepton decay channel in the boosted topol- ogy. The measured differential cross section is expressed as a function of the top quark transverse momentum at particle level and at parton level. The mea- sured distributions are compatible with the theoretical predictions of the Standard Model. The experimental techniques used in this measurement are discussed with emphasis on the jet reconstruction and on the identification of jets originating from b-quark fragmentation. The jet reconstruction is influenced by simultane- ous proton-proton collisions (pileup), and the mitigation of these pileup effects is studied. A novel pileup subtraction technique for jets is proposed using an ex- tension of the methods currently being employed by the LHC experiments. The new method has a good performance in removing the pileup contributions at the level of jet constituents. 1
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Studium kinematiky rozpadů top-antitopových párů v experimentu Atlas
Berta, Peter ; Kvita, Jiří (advisor) ; Soustružník, Karel (referee)
In this thesis, I deal with the measurement of the transverse momentum spectrum of the top quark produced in top-antitop pairs at the LHC at center of mass energy 7 TeV. The analysis is carried out within the ATLAS collaboration. In the single lepton decay channel, I have performed studies on the simulation which were necessary to obtain the final spectrum from real data. I describe basic event selection rules to reduce background events. I study the efficiency of top-antitop pairs reconstruction. I study the unfolding of the measured spectrum which corrects for effects caused by imperfect resolutions. At the end, I show the measured top quark transverse momentum spectrum obtained from my analysis.
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