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Refactoring of the data quality monitoring system in the Belle II vertex detector
Bártík, Jáchym ; Kvasnička, Peter (advisor) ; Červenkov, Daniel (referee)
This bachelor thesis deals with refactoring of a part of the Data Quality Monitoring (DQM) code for the Belle II vertex detector. In the second part of the thesis, monitoring of vertex detector half-shells movement over time is implemented. After summarizing the basic information about the Belle II experiment, its vertex detector and the basf2 software system, we will describe the functional behaviour of the data quality monitoring modules. We analyze the code of the TrackDQM and AlignDQM modules and fix several errors. As a part of refactoring, we divide the calculations into several simpler parts and significantly reduce the code duplication. Finally, we add histograms of residuals from the half-shells, which we evaluate on real data, fit and display as a function of time. The contribution of this work is a code that is easier to maintain and extend, as well as free of some obvious bugs. Another result is a discovery of periodical movements of vertex detector half-shells, the understanding of which can lead to improvement of detector alignment. 1
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Studium procesů s účastí kvarku b v experimentu Belle
Červenkov, Daniel ; Doležal, Zdeněk (advisor) ; Kepka, Oldřich (referee)
Title: Study of b-quark processes in the Belle experiment Author: Daniel Červenkov Department: Institute of Particle and Nuclear Physics Supervisor: Zdeněk Doležal Co-Supervisor: Karim Trabelsi Abstract: A study regarding the plausability of using the B0 → D∗ ρ± decay channel and the data set of the Belle experiment to measure sin(2φ1+φ3) has been carried out. Two fitters have been created. A time-independent one, which ex- hibits high stability and reports gratifying fit uncertainties, and a time-dependent one. During the testing of the latter we have discovered an EvtGen flaw and pro- posed a temporary workaround. Nevertheless, the time-dependent fitter fails to recover the correct values. More work will be needed to reach conclusive results. Keywords: B meson, CP violation, angular analysis, time-dependent, fitter
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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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Refactoring of the data quality monitoring system in the Belle II vertex detector
Bártík, Jáchym ; Kvasnička, Peter (advisor) ; Červenkov, Daniel (referee)
This bachelor thesis deals with refactoring of a part of the Data Quality Monitoring (DQM) code for the Belle II vertex detector. In the second part of the thesis, monitoring of vertex detector half-shells movement over time is implemented. After summarizing the basic information about the Belle II experiment, its vertex detector and the basf2 software system, we will describe the functional behaviour of the data quality monitoring modules. We analyze the code of the TrackDQM and AlignDQM modules and fix several errors. As a part of refactoring, we divide the calculations into several simpler parts and significantly reduce the code duplication. Finally, we add histograms of residuals from the half-shells, which we evaluate on real data, fit and display as a function of time. The contribution of this work is a code that is easier to maintain and extend, as well as free of some obvious bugs. Another result is a discovery of periodical movements of vertex detector half-shells, the understanding of which can lead to improvement of detector alignment. 1
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Simulation of noise in the Belle II strip vertex detector
Gruberová, Zuzana ; Kvasnička, Peter (advisor) ; Červenkov, Daniel (referee)
Title: Simulation of noise in the Belle II strip vertex detector Author: Zuzana Gruberová Institute: Institute of Particle and Nuclear Physics Supervisor: RNDr. Peter Kvasnička, Institute of Particle and Nuclear Physics Abstract: This bachelor thesis describes the development of strip noise simulation for the Belle II strip vertex detector (SVD). The overview part of the thesis describes the Belle II experiment and its detector system. The next part summarizes the basic princi- ples of semiconductor detectors with a focus on electronic noise. This section is followed by a more detailed description of Belle II SVD, its noise characteristics and simulation methods. The methods part introduces basic concepts of noise simulation using ma- chine learning methods, in particular, artificial neural networks. The experimental part describes the development and implementation of a production noise generator, and dis- cusses the performance, precision, and alternative solutions. Keywords: particle physics, Belle II, strip detector, noise, simulation, neural network 1
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Studium procesů s účastí kvarku b v experimentu Belle
Červenkov, Daniel ; Doležal, Zdeněk (advisor) ; Kepka, Oldřich (referee)
Title: Study of b-quark processes in the Belle experiment Author: Daniel Červenkov Department: Institute of Particle and Nuclear Physics Supervisor: Zdeněk Doležal Co-Supervisor: Karim Trabelsi Abstract: A study regarding the plausability of using the B0 → D∗ ρ± decay channel and the data set of the Belle experiment to measure sin(2φ1+φ3) has been carried out. Two fitters have been created. A time-independent one, which ex- hibits high stability and reports gratifying fit uncertainties, and a time-dependent one. During the testing of the latter we have discovered an EvtGen flaw and pro- posed a temporary workaround. Nevertheless, the time-dependent fitter fails to recover the correct values. More work will be needed to reach conclusive results. Keywords: B meson, CP violation, angular analysis, time-dependent, fitter
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