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Sterile neutrino physics at NOvA experiment.
Králik, Róbert ; Soustružník, Karel (advisor) ; Zálešák, Jaroslav (referee)
Title: Sterile neutrino physics at NOvA experiment Author: Róbert Králik Institute: Institute of Particle and Nuclear Physics Supervisor: RNDr. Karel Soustružník, Ph.D., Institute of Particle and Nuclear Physics Abstract: NOvA sterile neutrinos search via neutral current (NC) disappearance analysis is moving to a two-detector fit method to be able to fit to a wider range of sterile neutrino oscillations parameters. This introduces among other things a bigger contribution of the neutrino flux systematic uncertainty, which currently makes up the largest overall uncertainty for the ongoing NC disappearance anal- ysis. This thesis focuses on reducing this uncertainty and looks for different ways of making a more precise prediction of the neutrino flux. We point out Horn-Off analysis as the base for doing so and describe the production of a new Horn-Off simulation and the analysis of the Horn-Off results. We were not able to draw any conclusions that would reduce the NC disappearance systematic uncertainty, but the results showed herein can be helpful in the future attempts at a better neutrino flux prediction and a lower neutrino flux systematic uncertainty. Keywords: sterile neutrino neutrino flux NOvA 1
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Precision measurement of neutrino oscillations parameters
Dohnal, Tadeáš ; Leitner, Rupert (advisor) ; Stríženec, Pavol (referee) ; Zálešák, Jaroslav (referee)
The Daya Bay Reactor Neutrino Experiment, located in Southeast China, was de- signed to measure short baseline oscillation of electron antineutrinos originating from six 2.9 GWth nuclear reactors. In 2012, it discovered the nonzero value of the θ13 mixing angle and currently provides the world's most precise measurement of this neutrino os- cillation parameter. The goal of this thesis is to check the performance of the detector nonuniformity correction used by the Daya Bay experiment and then design a new im- proved version. For that purpose, the Daya Bay experiment is introduced including the procedure of the event reconstruction. Several types of signals are then studied in detail and later they are used to scrutinize the performance of the nonuniformity correction. Several issues are identified, most significantly an absence of radial dependence in the azimuthal part of the correction and inability to deal with dead photomultipliers. A new improved version of the correction that addresses these issues is then designed with the main goal to improve the precision of Daya Bay neutrino oscillation analyses, especially ongoing one which uses neutron capture on hydrogen. The impact of the new improved correction on said analyses is also assessed. 1
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Data analysis of the calorimeter CALICE
Bulánek, Boris ; Žáček, Josef (advisor) ; Zálešák, Jaroslav (referee)
In the present work we study the muon calibration of a hadrnic calorimeter. The calibration issue is divided into three parts. Description of the calibration principle and a comparison of the results with the previous results is described in the rst part. The method of the temperature and voltage corrections is presented in the second part. Also a comparison between the new and previous results is included. The last part is devoted to the study of myom track nding. The modied algorithm for searching muons was developed and compared with the default traknding algorithm.
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Studium kanálu J/Psi + foton v proton-protonových srážkách pomocí detektoru ATLAS na LHC
Vidláková, Zuzana ; Vrba, Václav (advisor) ; Zálešák, Jaroslav (referee)
Title: Analysis of J/Psi + photon production in proton-proton collisions on ATLAS at LHC Author: Bc. Zuzana Vidláková Department: Institute of particle and nuclear physics Supervisor: prom. fyz. Václav Vrba, CSc. (Academy of Sciences of the Czech Republic) Abstract: The subject of this thesis is physics connected to quarkonia and their studies at the ATLAS detector situated at LHC in CERN, Geneva. In this thesis, following topics are cov- ered: ATLAS detector, history of physics connected to quarkonia, production mechanisms of quarkonia, software used at CERN for data analysis and cross-section measurement of J/Psi + photon continuum. The analysis was done on behalf of the B-physics working group at ATLAS. Keywords: CERN, LHC, ATLAS, B-fyzika, quarkonia
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Detailed Investigation of Electron Antineutrino Oscillations in the Daya Bay Experiment
Roskovec, Bedřich ; Leitner, Rupert (advisor) ; Šimkovic, Fedor (referee) ; Zálešák, Jaroslav (referee)
Observed disappearance of reactor antineutrinos in the short baseline in Daya Bay can be explained by the phenomenon of neutrino flavour oscillations. The analysis in standard three- neutrino framework provides the best measurement of mixing angle of θ13 and the value of effective mass squared difference ∆m2 ee with comparable precision with other experiments. The unprecedented precision of Daya Bay motivates us to extend our search beyond standard three-neutrino oscillation scheme. It this thesis, we have explored two scenarios of possible physics Beyond Standard Model (BSM). We have tested the fundamental symmetry of the nature by searching for the Lorentz Invariance violation effect within the framework of the Standard-Model Extension (SME). Such an effect could be observed as a deviation from three- neutrino oscillation prediction in the oscillated antineutrino spectrum. Since we have not observed any significant deviation, we have been able to set the limits on the SME parameters. Some of the limits were measured for the first time while some turned out not to be competitive with the measurement of other experiments. We have also performed search for Non-standard Interactions (NSIs) in the Daya Bay. Being forbidden in the Standard Model, these interactions are predicted by BSM theories for which...
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Study of neutrino oscillations at the NOvA experiment
Nosek, Tomáš ; Soustružník, Karel (advisor) ; Roskovec, Bedřich (referee) ; Zálešák, Jaroslav (referee)
NOvA is a two detector long-baseline neutrino oscillation experiment using Fermilab's 700 kW NuMI neutrino beam. It studies the disappearance of muon (anti)neutrinos and the appearance of electron (anti)neutrinos in the beam over a distance of 810 km be- tween the detectors. This thesis presents the latest 2020 update of the NOvA neutrino oscillation analysis within the standard model of three neutrinos mixing. With about +50% new data in NuMI neutrino mode (+22% of the total available data) and nu- merous analysis upgrades compared to the previously reported results, the experiment has made over 4σ-significant observation of electron antineutrino appearance in muon antineutrino beam and constrained the oscillation parameters |∆m2 32|, sin2 θ23 and δCP. The text closely depicts the analysis and all its novelties and changes. A detailed inspec- tion is dedicated to the systematic uncertainties and their estimation and validation. Although statistical uncertainties currently dominate in these measurements, under- standing the major sources of systematic uncertainties and their correlations is vital for both the interpretation and precision of the results and for further improvements of the analysis. 1
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Sterile neutrino physics at NOvA experiment.
Králik, Róbert ; Soustružník, Karel (advisor) ; Zálešák, Jaroslav (referee)
Title: Sterile neutrino physics at NOvA experiment Author: Róbert Králik Institute: Institute of Particle and Nuclear Physics Supervisor: RNDr. Karel Soustružník, Ph.D., Institute of Particle and Nuclear Physics Abstract: NOvA sterile neutrinos search via neutral current (NC) disappearance analysis is moving to a two-detector fit method to be able to fit to a wider range of sterile neutrino oscillations parameters. This introduces among other things a bigger contribution of the neutrino flux systematic uncertainty, which currently makes up the largest overall uncertainty for the ongoing NC disappearance anal- ysis. This thesis focuses on reducing this uncertainty and looks for different ways of making a more precise prediction of the neutrino flux. We point out Horn-Off analysis as the base for doing so and describe the production of a new Horn-Off simulation and the analysis of the Horn-Off results. We were not able to draw any conclusions that would reduce the NC disappearance systematic uncertainty, but the results showed herein can be helpful in the future attempts at a better neutrino flux prediction and a lower neutrino flux systematic uncertainty. Keywords: sterile neutrino neutrino flux NOvA 1
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Studium vlastností neutrin pomocí NOvA detektoru
Jelínková, Zuzana ; Soustružník, Karel (advisor) ; Zálešák, Jaroslav (referee)
The NOνA experiment is a long-baseline neutrino oscillation experiment designed to measure electron neutrinos (νe) appearing in the NuMI beam, a muon neutrino (νµ) source at Fermilab. Its two detectors, Near and Far, are functionally identical active tracking calorimeters. This thesis is focused on the relative calibration of the Near Detector. The individual steps of the process, threshold, shadowing and attenuation calibration, are described. For the calibration, NOνA standardly uses cosmic muons. Alternative source, so called rock muons which are muons that originated from interactions of beam νµs with a rock surrounding the Near Detector, is introduced. The thesis guides through the development of selection criteria used to distinguish rock muon tracks from the data. Selected sample of rock muon tracks is used for the relative calibration and at each step the results are compared to the cosmic muons based calibration. The whole analysis is performed using simulated Monte Carlo data. 1
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