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Time-dependent CP violation in B0 → ηc KS0 decays at the Belle experiment, Alignment of the Belle II detector
Bilka, Tadeáš ; Doležal, Zdeněk (advisor)
This thesis deals with two independent yet closely related topics. In the first part, a measurement of branching fraction and time-dependent CP violation in B0 → ηcK0 S, ηc → K0 SK± π∓ decays is performed. This decay allows access to sin 2ϕ1, where ϕ1 is an angle of the unitary triangle of the Cabibbo-Kobayashi- Maskawa quark mixing matrix. The measurement is based on the entire dataset of the Belle experiment, which consists of 772 × 106 B meson pairs collected at the KEKB e+ e− collider. The extracted mixing-induced and direct CP- violation parameters read sin 2ϕ1 ≃ S = 0.59 ± 0.17 (stat) ± 0.07 (syst) and A = 0.16 ± 0.12 (stat) ± 0.06 (syst), respectively. The measured product of branching fractions B(B0 → ηcK0 S) × B(ηc → K0 SK± π∓ ) is (9.8 ± 0.6 (stat) ± 0.4 (syst)±2.3 (int))×10−6 , where the last uncertainty accounts for interference with non-resonant background. The second part deals with the alignment of the vertex detector and the central drift chamber of the Belle II experiment at the SuperKEKB collider, which is a next-generation Super-B-Factory. With the new pixel detector and the presented alignment method, Belle II achieves approximately twice better impact parameter resolutions than Belle. The presented alignment procedure involves a simultaneous determination of about sixty thousand...
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Time-dependent CP violation in B0 → ηc KS0 decays at the Belle experiment, Alignment of the Belle II detector
Bilka, Tadeáš ; Doležal, Zdeněk (advisor) ; Bielčík, Jaroslav (referee) ; Glazov, Alexander (referee)
This thesis deals with two independent yet closely related topics. In the first part, a measurement of branching fraction and time-dependent CP violation in B0 → ηcK0 S, ηc → K0 SK± π∓ decays is performed. This decay allows access to sin 2ϕ1, where ϕ1 is an angle of the unitary triangle of the Cabibbo-Kobayashi- Maskawa quark mixing matrix. The measurement is based on the entire dataset of the Belle experiment, which consists of 772 × 106 B meson pairs collected at the KEKB e+ e− collider. The extracted mixing-induced and direct CP- violation parameters read sin 2ϕ1 ≃ S = 0.59 ± 0.17 (stat) ± 0.07 (syst) and A = 0.16 ± 0.12 (stat) ± 0.06 (syst), respectively. The measured product of branching fractions B(B0 → ηcK0 S) × B(ηc → K0 SK± π∓ ) is (9.8 ± 0.6 (stat) ± 0.4 (syst)±2.3 (int))×10−6 , where the last uncertainty accounts for interference with non-resonant background. The second part deals with the alignment of the vertex detector and the central drift chamber of the Belle II experiment at the SuperKEKB collider, which is a next-generation Super-B-Factory. With the new pixel detector and the presented alignment method, Belle II achieves approximately twice better impact parameter resolutions than Belle. The presented alignment procedure involves a simultaneous determination of about sixty thousand...
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Simulation and analysis of tests of Belle II vertex detector sensors
Bilka, Tadeáš ; Kvasnička, Peter (advisor) ; Drásal, Zbyněk (referee)
This master thesis describes development and analysis of simulation, reconstruction and alignment for tests of Belle II vertex detector sensors as well as alignment procedure for the vertex detector itself. The first goal is to develop and test software tools which would allow analysis of sensor tests within common Belle II software framework. The second goal is to prepare the alignment chain for the vertex detector, being essential component of the detector calibration. First part of the thesis describes the Belle II experiment and its vertex detector, as well as the experimental beam test of the sensors and the common software framework. The theory behind the used alignment procedure utilizing Millepede II for alignment and General Broken Lines for track fitting is explained. Second part of the thesis then summarizes software tools developed or used and the results reached with these tools with emphasis on the alignment.
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Vývoj křemíkového detektoru pro experiment Belle II
Bilka, Tadeáš ; Kodyš, Peter (advisor) ; Černý, Karel (referee)
This bachelor thesis describes a simulation of the DEPFET pixel semiconductor detector. The DEPFET detector is a key part of a newly constructed Belle II particle detector being built in KEK, Japan. The simulation is made as a package for the basf2 framework, developed for the Belle II experiment. The goal of this thesis was to learn about the Belle II experiment, DEPFET pixel detector and the basf2 framework and to develop a simulation environment, depicting experimental setup at CERN's SPS accelerator in 2009. First part of this thesis describes the Belle II detector, the basf2 framework and summarizes basic information about silicon particle detectors, especially about the DEPFET technology. A task for the analysis of the data is to evaluate residuals after particle track fitting and cluster information in the pixel detector. Finally the simulation with thinned DEPFET sensor being developed for the Belle II is done.
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