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Browsing by Author "Szczurek, Antoni"

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    Exclusive reactions with light mesons: From low to high energies
    (Institute of Nuclear Physics Polish Academy of Sciences, 2014) Lebiedowicz, Piotr; Szczurek, Antoni; Sadzikowski, Mariusz; Turnau, Jacek
    In this Thesis, a theoretical analysis of exclusive production of mesons for various reactions in nucleon-nucleon collisions is presented. Detailed studies of the central exclusive production of the resonance states and the light dimeson pairs (π+π−, K+K−) within the Regge-based framework aswell as the exclusive production of forward neutral particles has been performed in a broad range of collision energy. Different aspects of production mechanism for the considered processes have been discussed, such as the model of soft pomeron, the absorption corrections, the off-shell effects of exchanged mesons. The cross section and many differential distributions were calculated and compared with existing experimental data wherever possible. Predictions for experiments at PANDA, RHIC, Tevatron and LHC energies have been presented. In addition, diffractive and electromagnetic production of the diboson pairs (γγ, W+W−, ZZ) at high energies has been considered in the framework of kt-factorization approach with the formalism of unintegrated gluon distribution functions. The production of technipions in dominant photonphoton channel as complementary possibility of search of particles beyond the Standard Modelat the LHC has been studied.
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    Processes with a hard scale at the LHC as a signature of partonic structure of the proton
    (Institute of Nuclear Physics Polish Academy of Sciences, 2015) Lewandowska, Emilia; Golec-Biernat, Krzysztof; Słomiński, Wojciech; Szczurek, Antoni
    The main aim of this thesis is a theoretical analysis of selected processes with a hard scale observed in the high-energy proton collisions at the LHC. These processes are considered in the limit of high energies available at the LHC, which allows a closer examination of the parton correlations inside the proton and, in consequence, leads to new information on the partonic structure of hadrons. The analysis carried out in this thesis concerns several problems. First, the Drell-Yan processes were analyzed in the formalism of the color glass condensate. The obtained results were compared with those obtained in the collinear approximation. The rest of the discussed issues concern the double parton scattering. In particular, we analyzed the problem of the specification of initial conditions for QCD evolution equations for double parton distributions, which satisfy non-trivial momentum and valence quark number sum rules. Within the double parton scattering studies, we analyzed the production of electroweak bosons W+W− and Z0Z0 taking into account the so called splitting terms in the QCD evolution equations. The found results show the importance of these terms for the predictions of the cross sections for the considered processes.
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    Production of pairs of mesons, leptons and quarks in ultraperipheral ultrarelativistic heavy ion collisions
    (Institute of Nuclear Physics Polish Academy of Sciences, 2015) Kłusek-Gawenda, Mariola; Szczurek, Antoni; Mrówczyński, Stanisław; Kowalski, Marek
    The main goal of the dissertation is theoretical determination of the total and differential cross sections for the production of pairs of mesons, leptons and quarks in ultraperipheral ultrarelativistic heavy ion collisions. The Equivalent Photon Approximation (EPA) in the impact parameter space has been used as a theoretical tool for calculation of the reaction mechanism in the electromagnetic processes. We have presented the predictions in a reference to STAR, PHENIX and ALICE experimental data. We have focused on the calculations with inclusion of the realistic charge distribution in nucleus and we have shown the difference between results for the realistic nucleus charge form factor and that for the monopole form factor often used in the literature. We have studied several elementary cross sections for fusion and we have compared our parametrizations of γγ→X1X2 processes to existing word experimental data. Furthermore, we have calculated the cross section for photoproduction of single and double ρ0 mesons, the latter due to a double-scattering mechanism. Additionally, we have studied the ρ0→π+π−and ρ0ρ0 → π+π−π+π−decays. Finally, we have discussed in detail electromagnetic excitation of gold and lead nuclei by soft photons and as well as the emission of neutrons from decays of the excited nuclear system.