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Quantum aspects of particle physics models with extended gauge symmetries
Sýkorová, Kateřina ; Malinský, Michal (advisor)
In this thesis, we study quantum aspects of the minimal renormalizable SO(10) Grand Unified Theory with the scalar sector consisting of 45 ⊕ 126 ⊕ 10C. It is an interesting candidate for a theory describing physics beyond the Standard model which has the potential to allow for proton lifetime prediction with Plank- scale-physics-induced theoretical uncertainties confined within the expected one- order-of-magnitude experimental proton lifetime improvement window. With the complete information about the numerical one-loop scalar mass spec- trum and analytical one-loop beta functions of all the dimensionless scalar cou- plings, we formulate consistency criteria that every viable region of the parameter space must satisfy; namely, we require the existence of a stable Standard-model- like vacuum, unification of gauge couplings and robustness of perturbative calcu- lations. Only narrow parameter space regions around symmetry breaking chains with SU(4)C × SU(2)L × U(1)R or SU(3)c × SU(2)L × SU(2)R × U(1)B−L intermedi- ate stages are demonstrated to be potentially realistic. Detailed analysis of the SO(10) Higgs model with 45⊕126 scalar sector indicates a preference for the for- mer option, mainly due to increased perturbative instability and phenomenologi- cally unsuitable values of energy scales predicted in the...
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Quantum aspects of particle physics models with extended gauge symmetries
Sýkorová, Kateřina ; Malinský, Michal (advisor) ; Beneš, Petr (referee) ; di Luzio, Luca (referee)
In this thesis, we study quantum aspects of the minimal renormalizable SO(10) Grand Unified Theory with the scalar sector consisting of 45 ⊕ 126 ⊕ 10C. It is an interesting candidate for a theory describing physics beyond the Standard model which has the potential to allow for proton lifetime prediction with Plank- scale-physics-induced theoretical uncertainties confined within the expected one- order-of-magnitude experimental proton lifetime improvement window. With the complete information about the numerical one-loop scalar mass spec- trum and analytical one-loop beta functions of all the dimensionless scalar cou- plings, we formulate consistency criteria that every viable region of the parameter space must satisfy; namely, we require the existence of a stable Standard-model- like vacuum, unification of gauge couplings and robustness of perturbative calcu- lations. Only narrow parameter space regions around symmetry breaking chains with SU(4)C × SU(2)L × U(1)R or SU(3)c × SU(2)L × SU(2)R × U(1)B−L intermedi- ate stages are demonstrated to be potentially realistic. Detailed analysis of the SO(10) Higgs model with 45⊕126 scalar sector indicates a preference for the for- mer option, mainly due to increased perturbative instability and phenomenologi- cally unsuitable values of energy scales predicted in the...
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Spolupráce na experimentu NA62 v CERN
Zamkovský, Michal ; Kampf, Karol (advisor) ; Faltová, Jana (referee)
1 Abstract The primary objective of this work is first encounter with the experiment NA62 which is in the process of preparation at European organization for nuclear research, CERN. Preparations and construction of a new experiment is a unique opportunity how to become part of the experimental group, comprehensive understanding of all part and good start for the future physical program. The work has two main parts. The first part involves physical motivation and possible direction of physical program. The second part covers all important experimental sections. 1
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Produkce jetů s velkou příčnou hybností na LHC
Podškubka, Radek ; Kupčo, Alexander (advisor) ; Lysák, Roman (referee)
In the first part of the thesis, theoretical uncertainties of jet cross-section have been calculated for proton-proton collision at the center of mass energy of 8 TeV. For jet identification the anti-kT algorithm with scale parameter R = 0.6 was used. As the calculations showed, the major contribution to the total theoretical uncertainty comes from the uncertainty of parton distribution function parameters. In the second part of the thesis, the angular distribution of dijet events produced in proton-proton collisions at the center of mass energy 8 TeV were simulated using Pythia 8 Monte Carlo event generator. New physics model of quark compositeness that should manifest itself by quark contact interaction was studied using angular distribution of dijet events. Three angular variables were discussed and these variables were used to calculate 95% CL lower limit on contact interaction scale. The results were compared and it emerged that the sensitivity to contact interaction signals varies for these variables.
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Study of the extremely rare decay K+ -> pi+nu nu with the NA62 experiment at CERN
Zamkovský, Michal ; Kampf, Karol (advisor)
The decay K+ → π+ ν¯ν has one of the most precisely predicted branch- ing ratio at the level of 10−10 . It is forbidden at the tree level, which makes it sensitive to the effects of new physics. The NA62 experiment at the CERN SPS aims to measure the branching ratio of the K+ → π+ ν¯ν using a unique decay-in-flight technique. NA62 took data so far in 2016-2018. The statistics acquired in 2016 allowed to reach Standard Model sensi- tivity for K+ → π+ ν¯ν. Owing to the statistics collected in 2017, NA62 surpasses the present best sensitivity. In the scope of this thesis, the preliminary result obtained from 2017 data sample is reported. 1
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Study of the extremely rare decay K+ -> pi+nu nu with the NA62 experiment at CERN
Zamkovský, Michal ; Kampf, Karol (advisor)
The decay K+ → π+ ν¯ν has one of the most precisely predicted branch- ing ratio at the level of 10−10 . It is forbidden at the tree level, which makes it sensitive to the effects of new physics. The NA62 experiment at the CERN SPS aims to measure the branching ratio of the K+ → π+ ν¯ν using a unique decay-in-flight technique. NA62 took data so far in 2016-2018. The statistics acquired in 2016 allowed to reach Standard Model sensi- tivity for K+ → π+ ν¯ν. Owing to the statistics collected in 2017, NA62 surpasses the present best sensitivity. In the scope of this thesis, the preliminary result obtained from 2017 data sample is reported. 1
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Study of the extremely rare decay K+ -> pi+nu nu with the NA62 experiment at CERN
Zamkovský, Michal ; Kampf, Karol (advisor) ; Blažek, Tomáš (referee) ; Řezníček, Pavel (referee)
The decay K+ → π+ ν¯ν has one of the most precisely predicted branch- ing ratio at the level of 10−10 . It is forbidden at the tree level, which makes it sensitive to the effects of new physics. The NA62 experiment at the CERN SPS aims to measure the branching ratio of the K+ → π+ ν¯ν using a unique decay-in-flight technique. NA62 took data so far in 2016-2018. The statistics acquired in 2016 allowed to reach Standard Model sensi- tivity for K+ → π+ ν¯ν. Owing to the statistics collected in 2017, NA62 surpasses the present best sensitivity. In the scope of this thesis, the preliminary result obtained from 2017 data sample is reported. 1
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Zkoumání vzácných procesů na experimentu NA62 v CERN
Jerhot, Jan ; Zamkovský, Michal (advisor) ; Pešek, Michael (referee)
Předmětem této práce je studie vzácného rozpadu π0 → ν¯ν. První část této práce obsahuje výpočet větvícího poměru tohoto rozpadu využitím dominantního rozpadu π0 → γγ a dis- kuzi teoretického pozadí. Druhou částí práce je příprava pro experimentální měření tohoto rozpadu, která je rozdělena na popis experimentu a použitých detektor· a na analýzu roz- padu K+ → π+ π0 na datech z roku 2016. Konkrétně je provedena analýza dominantního rozpadu π0 → γγ a účinnosti kalorimetru. 1
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Produkce jetů s velkou příčnou hybností na LHC
Podškubka, Radek ; Kupčo, Alexander (advisor) ; Lysák, Roman (referee)
In the first part of the thesis, theoretical uncertainties of jet cross-section have been calculated for proton-proton collision at the center of mass energy of 8 TeV. For jet identification the anti-kT algorithm with scale parameter R = 0.6 was used. As the calculations showed, the major contribution to the total theoretical uncertainty comes from the uncertainty of parton distribution function parameters. In the second part of the thesis, the angular distribution of dijet events produced in proton-proton collisions at the center of mass energy 8 TeV were simulated using Pythia 8 Monte Carlo event generator. New physics model of quark compositeness that should manifest itself by quark contact interaction was studied using angular distribution of dijet events. Three angular variables were discussed and these variables were used to calculate 95% CL lower limit on contact interaction scale. The results were compared and it emerged that the sensitivity to contact interaction signals varies for these variables.
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Effective interactions of the Euler-Heisenberg type in models of quantum field theory
Přeučil, Filip ; Hořejší, Jiří (advisor) ; Kampf, Karol (referee)
In the present thesis we study light-light scattering, which is a nonlinear effect occurring in quantum electrodynamics. The goal of this thesis is to study the low-energy effective theory (Lagrangians of Euler-Heisenberg type). The first part of the work is devoted to the derivation of the effective Lagrangian in spinor, scalar and vector QED using the amplitude matching of one-loop diagrams. The calculation for the case of vector QED is performed using the unitary gauge, which probably has not been done yet so far by other authors. In the second part, the effective Lagrangian for spinor QED is derived using functional methods. The essential point of the derivation is to calculate the determinant of the Dirac operator in constant background electromagnetic field. Powered by TCPDF (www.tcpdf.org)
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