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Measurement of the B0 meson lifetime at ATLAS detector
Řezníček, Pavel ; Doležal, Zdeněk (advisor) ; Cvach, Jaroslav (referee) ; Catmore, James Richard (referee)
Title: Measurement of the B0 d meson lifetime at ATLAS detector Author: Pavel Řezníček Department: Institute of Particle and Nuclear Physics Supervisor of the doctoral thesis: Dr. Zdeněk Doležal Supervisor's e-mail address: Zdenek.Dolezal@mff.cuni.cz Abstract: The lifetime of B0 d mesons is determined from their decays B0 d → J/ψK∗0 reconstructed in ATLAS experiment at the LHC using pp collision data at a center-of-mass energy of 7 TeV and corresponding to integrated luminosity of 40 pb−1 . The lifetime, extracted from the simultaneous unbinned maximum likelihood mass-lifetime fit, is 1.51±0.04 (stat.)±0.04 (syst.) ps. A total number of 2750±90 (stat.) signal B0 d decays are observed in the measurement, with a fit- ted B0 d mass of 5363.7 ± 1.2 (stat.) MeV. Both the extracted B0 d meson mass and lifetime are within the determined errors consistent with the world average values. Although the achieved precision is still significantly lower than the one of the world average value, the measurement successfully tested the feasibility of the fit-method and allowed to cross-check ATLAS detector performance. Keywords: CERN, LHC, ATLAS, B-physics, B-hadron, Lifetime
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The Belle II vertex detector alignment studies and prompt sin 2 phi analysis
Kandra, Jakub ; Doležal, Zdeněk (advisor)
This thesis is focused on the alignment studies of the vertex detector during first years of the Belle II detector operation and the first prompt sin 2ϕ1 analysis using the first rel- evant data collected by the detector. Firstly, the Belle II detector and the SuperKEKB accelerator is introduced. Secondly, the software framework and tools operation is ex- plained, then the alignment procedure and developed validation procedures are described in detail. Fourth section reports about the first years of the detector operation. Next three sections are related to different alignment studies during thee different periods of the vertex detector operation: the Phase 2, VXD Commissioning and beginning of the Phase 3 early. The last section covers the time-dependent CP Violation and mixing measurements performed using the data collected prior to the 11en of May 2020. 1
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The Belle II vertex detector alignment studies and prompt sin 2 phi analysis
Kandra, Jakub ; Doležal, Zdeněk (advisor) ; Kvita, Jiří (referee) ; Marčišovský, Michal (referee)
This thesis is focused on the alignment studies of the vertex detector during first years of the Belle II detector operation and the first prompt sin 2ϕ1 analysis using the first rel- evant data collected by the detector. Firstly, the Belle II detector and the SuperKEKB accelerator is introduced. Secondly, the software framework and tools operation is ex- plained, then the alignment procedure and developed validation procedures are described in detail. Fourth section reports about the first years of the detector operation. Next three sections are related to different alignment studies during thee different periods of the vertex detector operation: the Phase 2, VXD Commissioning and beginning of the Phase 3 early. The last section covers the time-dependent CP Violation and mixing measurements performed using the data collected prior to the 11en of May 2020. 1
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Study of the τ lepton decays at the Belle II experiment
Gruberová, Zuzana ; Doležal, Zdeněk (advisor) ; Kovaľ, Michal (referee)
This master thesis describes the measurement of the π0 reconstruction efficiency correc- tion using τ-pair events from the Belle II experiment. The review part of the thesis begins with an overview of the Standard Model and the Belle II experiment, its detector system and the simulation software. This is followed by the description the τ-pair events and the method used for measuring the π0 reconstruction efficiency correction. The central part focuses on the event selection and the extraction of the signal yields. The results present the measured values of the average and momentum dependent π0 reconstruction efficiency correction, an improved π0 selection optimized for τ-lepton analyses, and a dedicated study on photon timing selection requirements. 1
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Study of CP-violation at the Belle experiment
Červenkov, Daniel ; Doležal, Zdeněk (advisor)
We present a first measurement of time-dependent CP-violation in B0 → D∗∓ ρ± , where D∗∓ → D0 π. The analysis was performed using the final Belle dataset containing 772 × 106 B ¯B pairs collected at the KEKB e+ e− collider. Three D0 decay modes are analyzed, K∓ π± , K∓ π± π0 , and K∓ π± π∓ π± . Since the studied decay is a scalar → vector vector decay, three helicity configurations are present. Exploiting the helicity configura- tions via angular analysis, the time-dependent CP-violation parameters encoding 2ϕ1 +ϕ3 are obtained from the fit. 1
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Study of CP-violation at the Belle experiment
Červenkov, Daniel ; Doležal, Zdeněk (advisor)
We present a first measurement of time-dependent CP-violation in B0 → D∗∓ ρ± , where D∗∓ → D0 π. The analysis was performed using the final Belle dataset containing 772 × 106 B ¯B pairs collected at the KEKB e+ e− collider. Three D0 decay modes are analyzed, K∓ π± , K∓ π± π0 , and K∓ π± π∓ π± . Since the studied decay is a scalar → vector vector decay, three helicity configurations are present. Exploiting the helicity configura- tions via angular analysis, the time-dependent CP-violation parameters encoding 2ϕ1 +ϕ3 are obtained from the fit. 1
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Study of CP-violation at the Belle experiment
Červenkov, Daniel ; Doležal, Zdeněk (advisor) ; Bielčík, Jaroslav (referee) ; Scheirich, Daniel (referee)
We present a first measurement of time-dependent CP-violation in B0 → D∗∓ ρ± , where D∗∓ → D0 π. The analysis was performed using the final Belle dataset containing 772 × 106 B ¯B pairs collected at the KEKB e+ e− collider. Three D0 decay modes are analyzed, K∓ π± , K∓ π± π0 , and K∓ π± π∓ π± . Since the studied decay is a scalar → vector vector decay, three helicity configurations are present. Exploiting the helicity configura- tions via angular analysis, the time-dependent CP-violation parameters encoding 2ϕ1 +ϕ3 are obtained from the fit. 1
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Data Visualization Blender Add-On
Doležal, Zdeněk ; Milet, Tomáš (referee) ; Chlubna, Tomáš (advisor)
With growing interest in visualisation techniques, possibility to extend existing 3D computer graphics software by visualisation tools arises. Thesis deals with theory of data visualisation in general, selection of suitable visualisations, design, creation and publication of an data visualisation add-on for the open-source software Blender. Thanks to this work Blender is extended using its Python API by an interface used for data loading and commonly used charts generation. The published implementation was evaluated by user survey and it is available open-source.
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