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Some aspects of low-energy QCD at the precision frontier
Husek, Tomáš ; Kampf, Karol (advisor) ; Hořejší, Jiří (referee) ; Passemar, Emilie (referee)
Title: Some aspects of low-energy QCD at the precision frontier Author: Tomáš Husek Department/Institute: Institute of Particle and Nuclear Physics Supervisor of the doctoral thesis: doc. RNDr. Karol Kampf, Ph.D. Abstract: This thesis concentrates on some low-energy aspects of QCD, namely on those which are connected to the electromagnetic decays of lightest neutral pseudoscalar mesons. Calculations of radiative corrections to neutral pion decays (the Dalitz decay and the rare decay) and a novel model for the pion electro- magnetic transition form factor are subjects discussed in the attached papers, which this work is based on. The associated theoretical aspects including Chiral Perturbation Theory or the large-Nc limit are introduced. We also discuss the complications which arise when the calculations of radiative corrections for η(′) Dalitz decays are performed. Some details about the collaboration with experi- ments which incorporate the calculation of the published corrections are provided. Last but not least, some techniques related to loop integrals are shown. Keywords: Chiral Perturbation Theory, large-Nc limit, radiative corrections, pion electromagnetic transition form factor 1
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Hidden symmetry in classical and quantum physics
Karhan, Pavel ; Hořejší, Jiří (advisor) ; Novotný, Jiří (referee)
In the present work I study spontaneous symmetry breaking. This interesting phenomenon is an important part of the elementary particle physics and thanks to it, it is possible to generate masses of fermions and gauge bosons in the Standard Model. However, in this work I try to present a more general view and I bring up a few examples from various parts of physics, starting with classical mechanics and ending with quantum eld theory. I also study consequences of spontaneous symmetry breaking and discuss dierences in manifestations of this phenomenon in theories with nite and innite number of freedom. This work is primarily meant as a consistent survey of already known results supplemented with their sueciently detailed technical derivation in a comprehensible form.
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Search for Axion-Like Particles at the NA62 experiment
Jerhot, Jan ; Kampf, Karol (advisor) ; Hořejší, Jiří (referee)
The thesis instructively presents axions and axion-like particles as a plau- sible extension of the Standard Model of particle physics and discusses also the cosmological implications in the case of their existence as they present one of the most favourable dark matter candidates at given circumstances. The main part of the thesis is concerned with a search for axion-like particles at the NA62 experiment at CERN and a study of the gathered data and its impact on the data analysis.
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Some aspects of low-energy QCD at the precision frontier
Husek, Tomáš ; Kampf, Karol (advisor) ; Hořejší, Jiří (referee) ; Passemar, Emilie (referee)
Title: Some aspects of low-energy QCD at the precision frontier Author: Tomáš Husek Department/Institute: Institute of Particle and Nuclear Physics Supervisor of the doctoral thesis: doc. RNDr. Karol Kampf, Ph.D. Abstract: This thesis concentrates on some low-energy aspects of QCD, namely on those which are connected to the electromagnetic decays of lightest neutral pseudoscalar mesons. Calculations of radiative corrections to neutral pion decays (the Dalitz decay and the rare decay) and a novel model for the pion electro- magnetic transition form factor are subjects discussed in the attached papers, which this work is based on. The associated theoretical aspects including Chiral Perturbation Theory or the large-Nc limit are introduced. We also discuss the complications which arise when the calculations of radiative corrections for η(′) Dalitz decays are performed. Some details about the collaboration with experi- ments which incorporate the calculation of the published corrections are provided. Last but not least, some techniques related to loop integrals are shown. Keywords: Chiral Perturbation Theory, large-Nc limit, radiative corrections, pion electromagnetic transition form factor 1
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Radiation corrections to atomic spectra
Patkóš, Vojtěch ; Zamastil, Jaroslav (advisor) ; Hořejší, Jiří (referee) ; Čurík, Roman (referee)
Title: Radiation corrections to atomic spectra. Author: Vojtěch Patkóš Department: Department of chemical physics and optics Supervisor: doc. Mgr. Jaroslav Zamastil, Ph.D., KCHFO Abstract: In present time accuracy of spectroscopic measurements achieved fan- tastic accuracy 1 part in 10 to the power 14. If these measures are followed by theoretical calculations of similar accuracy we can test quantum electrodynamics and part of the standard model responsible for parity violating weak forces by comparing theory and experiment and set some of the basic physical constants like Rydberg constant, mass and radius of nucleus, constant of fine structure and it's variation in time etc. For achieving this kind of accuracy of calculations one must take into account so called radiation corrections. This thesis focus is on accurate calculation of the most important of them, the self-energy of electron in one-loop aproximation. Keywords: Quantum electrodynamics, radiation corrections, self-energy of elec- tron.
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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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Lagrangians for effective field theories and their properties
Trnka, Jaroslav ; Novotný, Jiří (advisor) ; Hořejší, Jiří (referee) ; Bydžovský, Petr (referee)
Název práce: Studium efektivních Lagrangianů a jejich aplikace Autor: Jaroslav Trnka Katedra: Ústav částicové a jaderné fyziky Vedoucí disertační práce: RNDr. Jiří Novotný, CSc., ÚČJF Abstrakt: V této práci studujeme různé aspekty efektivních teorií pole pro kvan- tovou chromodynamiku (QCD). V prvních dvou kapitolách se zaměříme na efek- tivní teorii pro resonance, která interpoluje mezi nízkoenergetickou efektivní teorií (Chirální poruchová teorie) a vysokoenergetickou QCD. V rámci této teorie studu- jeme jednosmyčkovou renormalizaci, jak z pohledu výpočetního pomocí SS-PP korelátoru, tak i čistě koncepčního studiem dynamicky generovaných stupňů vol- nosti. Ve čtvrté kapitole studujeme amplitudy rozptylu v rámci nelineárního sig- ma modelu, který představuje vedoucí člen nízkoenergetické efektivní teorie pro QCD. V návaznosti na nedávné objevy v rámci Yang-Mills teorie se nám podaří v rámci tohoto modelu zkonstruovat rekurzivní relace pro stromové amplitudy. Kromě čistě teoretické důležitosti tohoto faktu představuje tato metoda efektivní výpočetní nástroj nezávislý na formulaci amplitud pomocí Feynmanovských dia- gramů. Klíčová slova: efektivní teorie pole, kvantová chromodynamika, nelineární sigma model...
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Electroweak symmetry breaking by dynamically generated masses of quarks and leptons
Smetana, Adam ; Hošek, Jiří (advisor) ; Hořejší, Jiří (referee) ; Olejník, Štefan (referee)
Title: Electroweak symmetry breaking by dynamically generated masses of quarks and leptons Author: Adam Smetana Department: Institute of Particle and Nuclear Physics, Faculty of Mathematics and Physics, Charles University Supervisor: Ing. Jiří Hošek, DrSc., Department of Theoretical Physics, Nuclear Physics Institute, Academy of Sciences of the Czech Republic Abstract: The aim of the thesis is to study models of the electroweak symmetry breaking caused by dynamically generated masses of quarks and lep- tons. (1) We perform the basic analysis whether the main underlying idea, that the masses of only known fermions can provide the elec- troweak symmetry breaking, is actually feasible. For that we elaborate a two-composite-Higgs-doublet model of the top-quark and neutrino condensation. The model suggests rather large number, O(100), of right-handed neutrinos. (2) We analyze the model of strong Yukawa dynamics where the dynamical fermion mass generation is provided by exchanges of new elementary massive complex doublet scalar fields. We focus on solving the coupled Schwinger-Dyson equations for fermion and scalar self-energies by means of approximative methods. We doc- ument that strongly hierarchical mass spectra can be reproduced. (3) We elaborate the flavor gauge model where the dynamical fermion mass...
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Dynamical symmetry breaking in models with strong Yukawa interactions
Beneš, Petr ; Hošek, Jiří (advisor) ; Hořejší, Jiří (referee) ; Olejník, Štefan (referee)
Title: Dynamical symmetry breaking in models with strong Yukawa in- teractions Author: Petr Beneš Department: Institute of Theoretical Physics, Faculty of Mathematics and Physics, Charles University Supervisor: Ing. Jiří Hošek, DrSc., Department of Theoretical Physics, Nu- clear Physics Institute, Academy of Sciences of the Czech Repub- lic Abstract: The primary aim of the thesis is to explore the possibility of spon- taneous symmetry breaking by strong Yukawa dynamics. Tech- nically, the symmetry is assumed to be broken by formation of symmetry-breaking parts of both the scalar and the fermion prop- agators, rather than by the scalar vacuum expectation values. The idea is first introduced on an example of a toy model with the underlying symmetry being an Abelian one and later applied to a realistic model of electroweak interaction. In addition, the thesis also deals with some more general, model-independent is- sues, applicable not only to the discussed model of strong Yukawa dynamics, but to a wider class of models with dynamical mass generation. First of these issues is the problem of fermion flavor mixing in the presence of fermion self-energies with a general mo- mentum dependence. It is in particular shown how to define the CKM matrix in such models and argued that it can come out in principle...
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Scattering of the electroweak vector bosons
Morávek, Petr ; Hořejší, Jiří (advisor) ; Novotný, Jiří (referee)
In the present work we study the scattering of vector gauge bosons in the framework of higher dimensional theory of Kaluza-Klein type. This work provides an instructive introduction to the given problematics with all technical details of the relevant calculations. The basic ideas of the theory are demonstrated on a set of simple models. Particular attention is paid to the selection of consistent boundary conditions using the variational principle of least action, gauge invariance and tree-level unitarity of longitudinal gauge bosons scattering.
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