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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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Study of heavy particle production at D0
Benedikt, Tomáš ; Soustružník, Karel (advisor) ; Žáček, Josef (referee)
This work is about properties of top quark and methods of their measurements, which took place at D0 detector. At the beginning the history of the quark model is summarized followed by introduction to D0 detector at Tevatron collider in the USA. The rest of the work is dedicated to methods of measurements of important top quark properties. The most of attention is paid to measurements of production cross section and top quark's mass. The following topics are decay width, determination of the mass difference between top and antitop quarks and determination od top quark's electrical charge. In the end the newest values of top quark's properties are summarized.
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Measurement of the top quark properties
Schovancová, Jaroslava ; Chudoba, Jiří (advisor) ; Davídek, Tomáš (referee) ; Filipčič, Andrej (referee)
Title: Measurement of the top quark properties Author: Mgr. Jaroslava Schovancová Department: Institute of Physics, Academy of Sciences of the Czech Re- public Supervisor: RNDr. Jiří Chudoba, Ph.D., Institute of Physics, Academy of Sciences of the Czech Republic Abstract: This Thesis presents the ATLAS experiment measurement of the top quark differential cross-section as a function of pT, mass and rapidity of the t¯t system. A sample of approx. 4.7 fb−1 of the 2011 pp collision data at the center-of-mass energy of 7 TeV was analyzed. The differential spectra shapes in the t¯t system are consistent with the Standard Model and reason- ably described by the event generators. Several activities in the scope of ATLAS Distributed Computing are pre- sented, particularly in the area of operations, monitoring, automation, and development of the PanDA Workload Management System. Such activities aim to improve efficiency and facilitate the use of distributed computing re- sources and therefore contribute in supporting the ATLAS Physics Program. Keywords: ATLAS, top quark, differential cross-section, missing transverse energy, ATLAS Distributed Computing
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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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Measurement of the top quark properties
Schovancová, Jaroslava ; Chudoba, Jiří (advisor) ; Davídek, Tomáš (referee) ; Filipčič, Andrej (referee)
Title: Measurement of the top quark properties Author: Mgr. Jaroslava Schovancová Department: Institute of Physics, Academy of Sciences of the Czech Re- public Supervisor: RNDr. Jiří Chudoba, Ph.D., Institute of Physics, Academy of Sciences of the Czech Republic Abstract: This Thesis presents the ATLAS experiment measurement of the top quark differential cross-section as a function of pT, mass and rapidity of the t¯t system. A sample of approx. 4.7 fb−1 of the 2011 pp collision data at the center-of-mass energy of 7 TeV was analyzed. The differential spectra shapes in the t¯t system are consistent with the Standard Model and reason- ably described by the event generators. Several activities in the scope of ATLAS Distributed Computing are pre- sented, particularly in the area of operations, monitoring, automation, and development of the PanDA Workload Management System. Such activities aim to improve efficiency and facilitate the use of distributed computing re- sources and therefore contribute in supporting the ATLAS Physics Program. Keywords: ATLAS, top quark, differential cross-section, missing transverse energy, ATLAS Distributed Computing
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Study of heavy particle production at D0
Benedikt, Tomáš ; Soustružník, Karel (advisor) ; Žáček, Josef (referee)
This work is about properties of top quark and methods of their measurements, which took place at D0 detector. At the beginning the history of the quark model is summarized followed by introduction to D0 detector at Tevatron collider in the USA. The rest of the work is dedicated to methods of measurements of important top quark properties. The most of attention is paid to measurements of production cross section and top quark's mass. The following topics are decay width, determination of the mass difference between top and antitop quarks and determination od top quark's electrical charge. In the end the newest values of top quark's properties are summarized.
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