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Time resolution of TileCal and searches for heavy metastable particles
Pagáčová, Martina ; Leitner, Rupert (advisor) ; Němeček, Stanislav (referee)
Title: Time resolution of TileCal and searches for heavy metastable parti- cles Author: Martina Pagáčová Department: Institute of Particle and Nuclear Physics Supervisor: Doc. RNDr. Rupert Leitner, DrSc. Supervisor's e-mail address: Rupert.Leitner@cern.ch Abstract: In the present work, the timing of the ATLAS TileCal is stud- ied using the single hadron collision data. The time resolution and also the mean time response depend on the energy deposited in a given cell. The results are compared to the previous analysis with jets and muons. Precise time-of-flight measurement using TileCal can be used to identify the heavy long-lived particles predicted by the models of physics beyond the standard model. Their mass can be reconstructed by combining with the momentum measurement in the ATLAS inner detector. Finally, the mass resolution of an exotic particle with mass M = 600 GeV is estimated. Keywords: ATLAS experiment, TileCal, time resolution, stable massive particles
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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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Tile Calorimeter testbeam data analysis
Uhliarová, Lea ; Davídek, Tomáš (advisor) ; Dolejší, Jiří (referee)
Tile Calorimeter modules are regularly tested in the CERN SPS North Area, as they are an integral part of the ATLAS experiment at the Large Hadron Collider at CERN. In this thesis, test beam data from November 2018 were used for two separate analyses. Muon SPS H8 beam allowed for the review of radial electromagnetic cali- bration in the extended barrel module EBC65. Data from November 2018 test beam confirmed the correctness of previously established and used constants for rectifying uneven response in A, BC and D cell rows. In the second analysis, hadron beam from the SPS accelerator impinging on the Tile Calorimeter modules in the projective geometry was utilized. It served to determine the distribution of the mean energy in the calorimeter for hadronic showers in Tile Calorimeter at η varying from −0.05 up to −0.65. 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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Tests of Silicon detectors for the ATLAS detector upgrade
Mészárosová, Lucia ; Doležal, Zdeněk (advisor) ; Kodyš, Peter (referee)
The main goal of this bachelor thesis is to describe upcoming experiment ATLAS Upgrade and to compare it with present ATLAS, to describe upcoming tests of detectors and our own tests of prototypes of strip silicon detectors for the ATLAS Upgrade. Thesis is divided into three chapters. The first chapter is dedicated to the research facility CERN, specifically the present detector ATLAS, its inner detector and strip silicon detectors. In the next part there is characterized planned detector ATLAS Upgrade and again its inner detector and strip detectors. In the end of this part there is a tabular comparison of ATLAS and ATLAS Upgrade. The last chapter deals with the testing of detectors, at first routine testing of detectors in the past for ATLAS and planned routine tests for ATLAS Upgrade, and finally there are described our own tests of prototype the strip silicon detectors in FZÚ AV ČR supervised by Ing. Marcela Mikeštíková, Ph.D.
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Time resolution of TileCal and searches for heavy metastable particles
Pagáčová, Martina ; Leitner, Rupert (advisor) ; Němeček, Stanislav (referee)
Title: Time resolution of TileCal and searches for heavy metastable parti- cles Author: Martina Pagáčová Department: Institute of Particle and Nuclear Physics Supervisor: Doc. RNDr. Rupert Leitner, DrSc. Supervisor's e-mail address: Rupert.Leitner@cern.ch Abstract: In the present work, the timing of the ATLAS TileCal is stud- ied using the single hadron collision data. The time resolution and also the mean time response depend on the energy deposited in a given cell. The results are compared to the previous analysis with jets and muons. Precise time-of-flight measurement using TileCal can be used to identify the heavy long-lived particles predicted by the models of physics beyond the standard model. Their mass can be reconstructed by combining with the momentum measurement in the ATLAS inner detector. Finally, the mass resolution of an exotic particle with mass M = 600 GeV is estimated. Keywords: ATLAS experiment, TileCal, time resolution, stable massive particles
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