|
|
Study of ambiguities of Quantum Chromodynamics predictions in hard processes
Posolda, Petr ; Chýla, Jiří (advisor) ; Dolejší, Jiří (referee) ; Rameš, Jiří (referee)
The thesis is devoted to phenomenological investigation of ambiguities of QCD predictions coming from renormalization and factorization procedures. We studied predictions for e+ e− annihilation and jet production in proton-proton collisions. In the former case, we analyzed the dependence on RS up to fourth order at low and high energy region. We particularly focused on the Principle of Minimal Sensitivity as a guide for optimal choice of renormalization scheme. It is shown that a proper choice of RS is important especially at low energies where for example commonly used MS RS implies negative and unstable predictions, and that PMS optimized result don't suffer any of these drawbacks at studied cases. In the second part of the thesis, the dependence of NLO jet cross-section on renormalization and factorization scales is studied for total energy 1.8, 7 and 14 TeV. It is shown that PMS again provides qualitatively reasonable and stable results and seems to be relevant also for processes with hadrons in initial state. 1
|
|
|
Study of exotic hypernuclei
Posolda, Petr ; Mareš, Jiří (advisor) ; Kvasil, Jan (referee)
The thesis focuses on the study of properties of exotic hypernuclei, particularly of beryllium, carbon, oxygen and neon isotopes with and hyperons. Calculations were performed in the framework of the relativistic mean field theory (RMF) where a (hyper)nucleus is treated as a system of Dirac spinors (nucleons, hyperons) interacting via (mean) meson fields. The exotic hypernuclei were considered as axial symmetric. Up to now, hypernuclear calculations have been performed under assumption of spherical symmetry. This work thus extends hypernuclear calculations to the region of exotic, generally deformed systems. For the above nuclei, the numerical calculations of the binding energies and root mean square radii were performed. Moreover, we studied influence of the tensor interaction between meson and hyperon on the spin-orbit splitting. The results confirmed that the presence of the hyperon increases values of the binding energy of a system and on the contrary, it decreases its root mean square radius. We studied the possibility of the existence of the hyperon bound states in a nucleus. For the above isotopes, no bound states were found for the + hyperons. On the other hand, weekly bound states of the - hyperon are predicted for several isotopes.
|
|
|
Study of ambiguities of Quantum Chromodynamics predictions in hard processes
Posolda, Petr ; Chýla, Jiří (advisor) ; Dolejší, Jiří (referee) ; Rameš, Jiří (referee)
The thesis is devoted to phenomenological investigation of ambiguities of QCD predictions coming from renormalization and factorization procedures. We studied predictions for e+ e− annihilation and jet production in proton-proton collisions. In the former case, we analyzed the dependence on RS up to fourth order at low and high energy region. We particularly focused on the Principle of Minimal Sensitivity as a guide for optimal choice of renormalization scheme. It is shown that a proper choice of RS is important especially at low energies where for example commonly used MS RS implies negative and unstable predictions, and that PMS optimized result don't suffer any of these drawbacks at studied cases. In the second part of the thesis, the dependence of NLO jet cross-section on renormalization and factorization scales is studied for total energy 1.8, 7 and 14 TeV. It is shown that PMS again provides qualitatively reasonable and stable results and seems to be relevant also for processes with hadrons in initial state. 1
|
|
|
Study of exotic hypernuclei
Posolda, Petr ; Mareš, Jiří (advisor) ; Kvasil, Jan (referee)
The thesis focuses on the study of properties of exotic hypernuclei, particularly of beryllium, carbon, oxygen and neon isotopes with and hyperons. Calculations were performed in the framework of the relativistic mean field theory (RMF) where a (hyper)nucleus is treated as a system of Dirac spinors (nucleons, hyperons) interacting via (mean) meson fields. The exotic hypernuclei were considered as axial symmetric. Up to now, hypernuclear calculations have been performed under assumption of spherical symmetry. This work thus extends hypernuclear calculations to the region of exotic, generally deformed systems. For the above nuclei, the numerical calculations of the binding energies and root mean square radii were performed. Moreover, we studied influence of the tensor interaction between meson and hyperon on the spin-orbit splitting. The results confirmed that the presence of the hyperon increases values of the binding energy of a system and on the contrary, it decreases its root mean square radius. We studied the possibility of the existence of the hyperon bound states in a nucleus. For the above isotopes, no bound states were found for the + hyperons. On the other hand, weekly bound states of the - hyperon are predicted for several isotopes.
|
guest ::
