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Elastic Scattering at the LHC
Kašpar, Jan ; Kundrát, Vojtěch (vedoucí práce) ; Valkárová, Alice (oponent) ; Kupčo, Alexander (oponent)
Na'zev pra'ce: Elasticky' rozptyl na LHC Autor: Jan Kasˇpar Katedra: U' stav cˇa'sticove' a jaderne' fyziky Vedoucı' doktorske' pra'ce: RNDr. Vojtečh Kundra't, DrSc., Fyzika'lnı' u'stav AV CŘ, v. v. i. Abstrakt: Elasticky' rozptyl protonu˚, prěstozě proces zda'nliveˇ jednoduchy', prědstavuje pro teorii sta'le velkou vy'zvu. V te'to pra'ci se zaby'va'me elasticky'm rozptylem z teoreticke'ho i experimenta'lnı'ho hlediska. V teoreticke' cˇa'sti shrneme neˇkolik modelu˚ a jejich prědpoveďi pro LHC. V diskuzi veňovane' interferenci mezi Coulombickou a hadronovou interakcı' prědstavı'me novy' eikona'lovy' vy'pocět do vsěch rˇa'du˚ v konstanteˇ jemne' struktury α. V experimenta'lnı' cˇa'sti pra'ce popı'sěme experiment TOTEM, ktery' je mimo jine' zasvečen meřěnı' elasticke'ho rozptylu protonu˚ na LHC. Toto meřěnı' je realizova'no prědevsˇı'm detektory v rˇı'msky'ch hrncı'ch (Rˇ H). To jsou pohyblive' vakuove' na'doby zasouvajı'cı' se do urychlovacˇove' trubice stovky metru˚ od interakcňı'ho bodu. Dı'ky tomu jsou Rˇ H schopny detekovat cˇa'stice rozpty'lene' do velmi maly'ch u'hlu˚. V pra'ci takte'zˇ diskutujeme neˇktere' aspekty simulacňı'ho a rekonstrukcňı'ho softwaru pro Rˇ H. Velky' prostor je veňova'n alignmentu Rˇ H, tj. urcěnı'pozic senzoru˚ v Rˇ H navza'jem i vu˚cˇi svazku. V za'veřu...
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Proton-Proton Interactions at the ATLAS Experiment at the LHC Accelerator
Přibyl, Lukáš ; Němeček, Stanislav (vedoucí práce) ; Soustružník, Karel (oponent) ; Kupčo, Alexander (oponent)
In this thesis the potential of the ATLAS detector to exclude or discover quark compositeness is studied in detail. There were four dierent sensitive analysis methods developed for this purpose. These methods use a detailed information about inclusive dijet pT-spectrum or dijet angular distribution and two of them use Bayesian technique (as is usual in similar analyses at Tevatron). For all four methods a larger number of systematic errors was taken into account and their inuence was studied in detail too. It is also shown, that the early data exclusion limit on quark compositeness reachable by the ATLAS experiment is + LL = 10.3 TeV at 95% C.L with 100 pb 1 of collision data of a sucient quality. This limit is considerably higher than the current limit known from Tevatron: + LL = 2.7 TeV at 95% C.L. The highest exclusion limit on quark compositeness with expected total amount of data to be collected by the ATLAS experiment is above 22 TeV, assuming 3% jet energy scale uncertainty.
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QCD a difrakce na experimentu ATLAS na LHC urychlovači
Kepka, Oldřich ; Kupčo, Alexander (vedoucí práce) ; Favart, Laurent (oponent) ; Stirling, W.J. (oponent)
This thesis is devoted to study the hard diffractive and exclusive events at the experiment ATLAS. Right after the start-up of a new proton accelerator LHC in CERN they will be identied using the rapidity gap method. We therefore developed an alternative denition of the observed energy in the ATLAS calorimeter to identify diffractive and exclusive events. During the high luminosity operation of the accelerator, forward detectors (AFP) recently proposed to be installed far from the interaction point approaching the beam at few millimeters will allow to tag the intact scattered protons in these events unambiguously. The simplest exclusive production is due to the exchange of two photons. We implemented twophoton exchanges in FPMC generator and analyzed the two-photon production of W and Z-pairs decaying leptonically to calculate sensitivities on triple and quartic anomalous gauge couplings of electroweak boson to photons. The obtained results are remarkable mainly for the quartic couplings. Their current limits can be improved by almost two orders of magnitude with early data and by four orders of magnitude using large luminosity and AFP detectors. In addition, we used two-photon dimuon events to determine the time needed to align one of the AFP stations with respect to beam to a desired precision. Another...
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QCD analýza multijetových případů v proton-antiprotonových srážkách na urychlovači Tevatron
Kepka, Oldřich ; Kupčo, Alexander (vedoucí práce) ; Žáček, Josef (oponent)
The recent developments in theoretical calculations (code NLOJET++) allow us to evaluate the 3-jet observables at the next-to-leading order precision. In this diploma thesis we investigate the potential of using 3-jet observables for the measurement of strong coupling s at hadron colliders. First, we analyze the inclusive jet cross section measured by DO Collaboration, determine s and demonstrate its running in a similar way as was previously done by CDF Collaboration. In the second part of the thesis, we analyze the DO measurement of dijet azimuthal decorrelations. With this choice of 3-jet observable we were able to achieve a better precision of s than in the previous s measurements based on the inclusive jet production.
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