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Haidarali, Mohammad Reza. "Local and distortional buckling behaviour of cold-formed steel Z section beams." Thesis, Imperial College London, 2011. http://hdl.handle.net/10044/1/6992.
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The economic use of cold-formed steel members means that buckling and the possible loss of effectiveness it produces are important features of design. Cross-sectional instabilities in laterally-restrained cold-formed steel beams include local and distortional buckling. The prediction of the true buckling behaviour of cold-formed steel beams accounting for all governing features such as geometrical imperfections, spread of yielding, postbuckling etc. has been possible with the development of advanced numerical modelling. In this thesis, the finite element (FE) method (ABAQUS) has been used to develop numerical analyses to study the buckling behaviour of laterally-restrained cold-formed steel lipped Z-section beams. The FE models were verified against a series of four-point bending tests available from previous research, with special references to material and geometrical nonlinearities. Two sets of analyses have been conducted: FE analyses allowing for both local and distortional buckling and ones allowing for local buckling while distortional buckling is restrained using appropriate boundary conditions. For the former, the controlling buckling mode (local, distortional or combined) at different stages of loading (up to, at and beyond maximum load) has been realized. Comparing the results of two sets of analyses, the effect of distortional buckling on performance for different geometric proportions has been studied. The effect of the lip size, flange width, angle of inclination of the edge stiffener (lip), size and position of the intermediate stiffener and material strength as well as the interaction between them on both the ultimate strength and the buckling of cold-formed Z-section beams has been investigated. Limits for optimum design of the section were proposed. Depending on the geometric properties and material strength of the section, transitions between local, distortional and combined local/distortional buckling were observed. The lip/flange interaction including the interaction between the edge stiffener (lip) and the intermediate stiffener was the key governing feature of behaviour. The effect of the linear moment gradient and sharply varying bending moment on both the ultimate strength and the buckling of cold-formed Z sections was investigated. The latter occurred in two-span continuous beams subject to uniformly distributed loading. The results of moment gradient cases were compared with those of pure bending cases. The suitability of the design treatments available in Eurocode 3 (EC3) for local, combined local/distortional and distortional buckling of cold-formed Z-section beams was assessed. Overall, the EC3 predictions for cross-sectional bending resistances were unconservative. Shortcomings were identified and some suggestions for improvements were made. This included improvements in plate buckling factors for edge-stiffened compression flanges.
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Gonzalo, San Martin. "The cross section and forward backward asymmetry for Z - u + u at ALEPH." Thesis, Imperial College London, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267246.
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Wieland, Todd M. "Scale effects in buckling, postbuckling and crippling of graphite-epoxy Z-section stiffeners." Diss., Virginia Tech, 1991. http://hdl.handle.net/10919/39973.
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Lath, Amitabh. "A precise measurement of the left-right cross section asymmetry in Z boson production." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/32635.
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Cortese, Scott D. "Investigation of Single Span Z-Section Purlins Supporting Standing Seam Roof Systems Considering Distortional Buckling." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/34198.
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Presently, the industry accepted method for the determination of the governing buckling strength for cold-formed purlins supporting a standing seam metal roof system is the 1996 AISI Specification for the Design of Cold-Formed Steel Structural Members, which contains provisions for local and lateral buckling. Previous research has determined that the AISI provisions for local buckling strength predictions of cold-formed purlins are highly unconservative and that the AISI provisions for lateral buckling strength predictions of cold-formed purlins are overly conservative. Therefore, a more accurate "hand" method is needed to predict the buckling strengths of cold-formed purlins supporting standing seam roof systems. The primary objective of this study is to investigate the accuracy of the Hancock Method, which predicts distortional buckling strengths, as compared to the 1996 AISI Specification provisions for local and lateral buckling.
This study used the experimental results of 62 third point laterally braced tests and 12 laterally unbraced tests. All tests were simple span, cold-formed Z-section supported standing seam roof systems. The local, lateral, and distortional buckling strengths were predicted for each test using the aforementioned methods. These results were compared to the experimentally obtained data and then to each other to determine the most accurate strength prediction method.
Based on the results of this study, the Hancock Method for the prediction of distortional buckling strength was the most accurate method for third point braced purlins supporting standing seam roof systems. In addition, a resistance factor was developed to account for the variation between the experimental and the Hancock Method's predicted strengths.Master of Science
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Kormoll, Kathrin. "Mass reconstruction techniques and cross section measurement for Z→ττ→eμ+4υ with the ATLAS experiment." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-110173.
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Die Suche nach dem Higgs Boson ist ein zentraler Forschungsschwerpunkt der modernen Teilchenphysik. Zum einen ist das Higgs Boson das einzige bislang unentdeckte Teilchen des Standard Modells. Zum anderen gibt seine mögliche Entdeckung eine bessere Einsicht in die Natur neuer Physik. Mit der Inbetriebnahme des Large Hadron Colliders, LHC, am europäischen Kernforschungszentrum CERN bei Genf konnten Proton-Proton Kollisionen mit bislang unerreichten Schwerpunktsenergien von √s = 7 TeV beziehungsweise √s = 8 TeV erzielt werden.
In der vorliegenden Arbeit wird die Messung des Wechselwirkungsquerschnitts pp→Z/γ→τ⁺τ⁻ im gemischten leptonischen Endzustand mit Daten des ATLAS Detektors durchgeführt. Der Zerfall der kohärenten Summe aus Photon, γ, und Z Boson in zwei τ -Leptonen ist ein irreduzibler Untergrund von Higgs Boson Zerfällen in zwei τ -Leptonen. Eine genaue Kenntniss des Massenspektrums sowie dessen Normierung ist deswegen für die Higgs Boson Suche essentiell. Die verwendeten Daten entsprechen einer integrierten Luminosität von L = 35,51 pb⁻¹ bei einer Schwerpunktsenergie von √s = 7 TeV. Die Messung erzielt einen Wechselwirkungsquerschnitt von σ×BR(Z→ττ ) = (1041 ± 143 ± 74 ± 35) pb. Die angegebenen Unsicherheiten entsprechen den statistischen, den systematischen und den Unsicherheiten aus Luminositätsmessungen. Das Ergebnis stimmt mit dem theoretisch bestimmten Wert sowie dem Ergebnis anderer Experimente innerhalb seiner Unsicherheiten überein.
Im zweiten Teil der Arbeit werden verschiedene Massenrekonstruktionsmethoden von Zerfällen in zwei τ-Leptonen untersucht. Die Analyse konzentriert sich dabei auf Higgs Bosonen, der minimalen supersymmetrischen Erweiterung des Standard Modells; insbesondere auf deren Zerfall in zwei τ-Leptonen und weiter in den gemischten leptonischen Endzustand, Φ→τ⁺τ⁻→eμ+4υ. Die untersuchten Massenrekonstruktionsmethoden sind die sichtbare Masse, die effektive Masse, sowie die früh- und spät-projizierte transversale Masse. Weiterhin werden Abhängigkeiten der Massenverteilungen vom transversalen Impuls der Leptonen des Endzustandes, sowie der fehlenden transversalen Energie festgestellt. Eine Abhängigkeit vom transversalen Impuls des energiereichsten Jets hingegen konnte nicht nachgewiesen werden. Eine mögliche Eliminierung der Variablenabhängigkeiten wird untersucht, zeigt jedoch dass sie zu einer schlechteren Trennung zwischen Signal und Untergrundprozessen sowie einer schlechteren Auflösung unterschiedlicher Higgs Boson Massen führt. Mit der Kalibrierung der berechneten Massen der verschiedenen Rekonstruktionstechniken wird die Arbeit abgeschlossen.
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Melachrinos, Constantinos. "The Muon Detection System and W Z --> 3l̳(e̳, [mu]) cross section measurement at CMS." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/44757.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Physics, 2008.In title on title page, "[mu]" appears as lower case Greek letter; and, double underscored "l" and "e" appear as script.
Includes bibliographical references (p. 57-59).
The startup of the Large Hadron Collider will allow scientists to probe energy scales that existed picoseconds after the Big Bang. Monte Carlo samples of many Standard Model processes are produced to simulate the conditions in the Compact Muon Solenoid detector. Data analysis techniques are developed to measure the cross section of the W Z --> 3l(e, [mu]) decay channel. The results are [sgima]all = 723.4 ± 27.6(stat.) ± 144.7(syst.) fb for integrated luminosity 1 fb-1. Cross section measurements deduced by our data analysis techniques agree with the theoretical predictions, [sigma] pred. all = 708 ± 26.6 fb. The selection of W Z --> 3l events gave 43.5 ± 6.6 signal events with 6.4 ± 2.5 background events, enough to claim an observation at the level of five standard deviations. The understanding of this process will aid in the search for the Higgs boson, as well as in the search for new physics in the early stages of the operation of the detector.
by Constantinos Melachrinos.
S.B.
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Shrestha, Shruti. "A measurement of Z(vv̄)[photon] cross section and limits on anomalous triple gauge couplings at [square root of]s = 7 TeV using CMS." Diss., Kansas State University, 2013. http://hdl.handle.net/2097/15316.
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Doctor of PhilosophyDepartment of Physics
Yurii Maravin
In this thesis, the first measurement of Z(vv̄)[photon] cross section in pp collisions at [square root of]s = 7 TeV has been done using data collected by the CMS detector. The measured cross section is 21.3 ± 4.2 (stat.) ± 4.3 (syst.) ± 0.5 (lumi.) fb. This measurement is based on the observations of events with missing transverse energy in excess of 130 GeV and photon in the rapidity range [eta] < 1.44 of transverse momentum in excess of 145 GeV in a data sample corresponding to an integrated luminosity of 5 fb⁻¹. This measured cross section is in good agreement with the theoretical prediction of 21.9 ± 1.1 fb from BAUR. Further, neutral triple gauge couplings involving Z bosons and photons have been studied. No evidence for the presence of such couplings is observed and is in agreement with the predictions of the standard model. We set the most stringent limits to date on these triple gauge couplings.
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Matoušek, Karel. "Řešení problematiky ohýbání dílců z tenkostěnných profilů." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2010. http://www.nusl.cz/ntk/nusl-229347.
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Reconnaissance of problems and parameters of square hollow profile bend. Finding (identification) of deformation of cross-section. Finding of suitability of unannealed material for component part. Finding of mechanical characteristics of welds and influence of their bend position. This finding was done on the basis of comparison of tensile tests and consequently aplicated to specific part where the suitability for use of unannealed material were proved.
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Wang, Qun. "Measurement of the differential cross section of Z boson production in association with jets at the LHC." Doctoral thesis, Universite Libre de Bruxelles, 2018. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/271719.
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This thesis presents the measurement of the differential cross section of Z boson pro-duction in association with jets (Z+jets) in proton-proton collision at the center-of-massenergy of 13 TeV. The data has been recorded with the CMS detector at the LHC duringthe year 2015, corresponding to an integrated luminosity of 2.19 fb −1 .A study of theCMS muon High Level Trigger (HLT) with the data collected in 2016 is also presented.The goal of analysis is to perform a first measurement at 13 TeV of the cross sections ofZ+jets as a function of the jet multiplicity, its dependence on the transverse momentumof the Z boson, the jet kinematic variables (transverse momentum and rapidity), thescalar sum of the jet momenta, and the balance in the transverse momentum betweenthe reconstructed jet recoil and the Z boson. The results are obtained by correctingthe detector effects, and are unfolded to particle level. The measurement are com-pared to four predictions using different approximations: at the leading-order (LO),next-to-leading-order (NLO) and next-to-next-to-leading order (NNLO) accuracy. Thefirst two calculations used M AD G RAPH 5_ A MC@NLO interfaced with PYTHIA 8 for theparton showering and hadronisation, one of which includes matrix elements (MEs) atLO, another includes one-loop corrections (NLO). The third is a fixed-order calculationwith NNLO accuracy for Z+1 jet using the N -jettiness subtraction scheme (N jetti ). Thefourth uses the GENEVA program with an NNLO calculation combined with higher-order resummation.A series of studies on the HLT double muon trigger are also included. Since 2015 theLHC reached higher luminosity, more events are produced inside the CMS detector persecond, which resulted in more challenges for the trigger system. The work presentedincludes the monitoring, validation and the calibration of the muon trigger paths since2016.Doctorat en Sciences
info:eu-repo/semantics/nonPublished
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Seek, Michael Walter. "Prediction of Lateral Restraint Forces in Sloped Z-section Supported Roof Systems Using the Component Stiffness Method." Diss., Virginia Tech, 2007. http://hdl.handle.net/10919/28357.
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Z-sections are widely used as secondary members in metal building roof systems. Lateral restraints are required to maintain the stability of a Z-section roof system and provide resistance to the lateral forces generated by the slope of the roof and the effects due to the rotation of the principal axes of the Z-section relative to the plane of the roof sheathing. The behavior of Z-sections in roof systems is complex as they act in conjunction with the roof sheathing as a system and as a light gage cold formed member, is subject to local cross section deformations.
The goal of this research program was to provide a means of predicting lateral restraint forces in Z-section supported roof systems. The research program began with laboratory tests to measure lateral restraint forces in single and multiple span sloped roof systems. A description of the test apparatus and procedure as well as the results of the 40 tests performed is provided in Appendix II.
To better understand the need for lateral restraints and to provide a means of testing different variables of the roof system, two types of finite element models were developed and are discussed in detail in appended Paper I. The first finite element model is simplified model that uses frame stiffness elements to represent the purlin and sheathing. This model has been used extensively by previous researchers and modifications were made to improve correlation with test results. The second model is more rigorous and uses shell finite elements to represent the Z-section and sheathing.
The shell finite element model was used to develop a calculation procedure referred to as the Component Stiffness Method for predicting the lateral restraint forces in Z-section roof systems. The method uses flexural and torsional mechanics to describe the behavior of the Z-section subject to uniform gravity loads. The forces generated by the system of Z-sections are resisted by the "components" of the system: the lateral restraints, the sheathing and Z-section-to-rafter connection. The mechanics of purlin behavior providing the basis for this method are discussed in appended Paper II. The development of the method and the application of the method to supports restraints and interior restraints are provided in appended papers III, IV and V.Ph. D.
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Ball, Gordon. "Cross section studies of the Z and neutral supersymmetric Higgs bosons decaying to tau leptons at CMS." Thesis, Imperial College London, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.544292.
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Seifert, Frank. "Z to tau tau Cross Section Measurement and Liquid-Argon Calorimeter Performance at High Rates at the ATLAS Experiment." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-102754.
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In this study, a measurement of the production cross section of Standard Model Z bosons in proton-proton collisions in the decay channel Z to tau tau is performed with data of 1.34 fb-1 - 1.55fb-1 recorded by the ATLAS experiment at the LHC at a center-of-mass energy of 7 TeV. An event selection of the data is applied in order to obtain a sample enriched with Z to tau tau events. After background estimations using data and Monte Carlo (MC) simulations, the fiducial cross sections in the sub-channels Z to tau tau to e tau_h + 3nu and Z to tau tau to mu tau_h + 3nu are measured. Together with the geometrical and kinematical acceptance, A_Z, and the well known tau lepton branching fractions, these results are combined to a total inclusive Z to tau tau cross section. A_Z is obtained from MC studies only, and the combination of the channels is done including statistical and systematical uncertainties using the BLUE method. The result is a measured total inclusive cross section of 914.4 plus minus 14.6(stat) plus minus 95.1(syst) plus minus 33.8(lumi) pb. This is in agreement with theoretical predictions from NNLO calculations of 964 plus minus 48 pb and also with measurements previously performed by the ATLAS and CMS experiments. With the increased amount of data, the statistical uncertainty could be reduced significantly compared to previous measurements. Furthermore, a testbeam analysis is performed to study the operation of the electromagnetic and hadronic endcap calorimeters, EMEC and HEC, and of the forward calorimeter, FCal, in the high particle fluxes expected for the upgraded LHC. The high voltage return currents of the EMEC module are analysed in dependence of the beam intensity. The results are compared to model predictions and simulations to extract the point of critical operation. Overall, the results for the critical beam intensities and the critical high voltage currents are in agreement with the predictions, but the assigned uncertainties are rather large. The general behaviour of the high voltage current in dependence of the beam intensity above the critical intensity could be confirmed very well. The testbeam data show that the EMEC can be operated up to highest LHC luminosities, and that ATLAS conserves its excellent calorimeter performance in this detector areaIn dieser Studie wird eine Wirkungsquerschnittsmessung des Standardmodell-Z-Bosons im Zerfallskanal Z nach tau tau mit Kollisionsereignissen entsprechend 1.34 fb-1 bis 1.55 fb-1 aufgezeichneter Daten des ATLAS-Experiments am LHC bei einer Schwerpunktsenergie von 7 TeV durchgefuehrt. Hierbei kommt eine spezielle Ereignisselektion der Daten zum Einsatz, die zum Ziel hat, einen mit Z nach tau tau Ereignissen angereicherten Datensatz zu erhalten. Nach einer Untergrundabschaetzung mit Hilfe von experimentellen Daten und Monte-Carlo(MC)-Simulationen wird eine spezifische Wirkungsquerschnittsmessung in den Unterkanaelen Z nach tau tau nach e tau_h + 3nu und Z nach tau tau nach mu tau_h + 3nu erreicht, welche zunaechst nur Ereignisse in der geometrischen und kinematischen Akzeptanzregion umfasst. Zusammen mit der Selektionseffizienz dieser Akzeptanzregion, A_Z, und den bekannten Tau-Lepton-Verzweigungsverhaeltnissen koennen diese Ergebnisse zu einem totalen, inklusiven Z nach tau tau Wirkungsquerschnitt kombiniert werden. Hierbei wird A_Z ausschliesslich aus MC-Studien bestimmt und die Kombination unter Beruecksichtigung der statistischen und systematischen Fehler der Einzelkanaele mit der BLUE-Methode durchgefuehrt. Das Ergebnis ist ein totaler, inklusiver Wirkungsquerschnitt von 914.4 plus minus 14.6(stat) plus minus 95.1(syst) plus minus 33.8(lumi) pb. Dies stimmt innerhalb der Messunsicherheiten sowohl mit theoretischen Vorhersagen aus NNLO Rechnungen von: 964 plus minus 48 pb als auch mit Messungen, die zuvor im Zuge der ATLAS- und CMS-Experimente durchgefuehrt wurden, ueberein. Im Vergleich zu den bisherigen Messungen koennen die statistischen Fehler mit dem groesseren Datensatz deutlich reduziert werden. Weiterhin wird eine Teststrahlstudie zur Pruefung der Funktionalitaet der elektromagnetischen und hadronischen Endkappenkalorimeter, EMEC und HEC, und des Vorwaertskalorimeters FCal in den zukuenftigen, hohen Teilchenflussdichten des verbesserten LHC praesentiert. Die Hochspannungsstroeme des EMEC-Moduls werden in Abhaengigkeit von der Strahlintensitaet analysiert. Weiterhin werden die Ergebnisse mit Modellvorhersagen und Simulationen verglichen, um die Punkte nichtlinearen (kritischen) Betriebes zu extrahieren. Die Ergebnisse fuer die kritische Strahlintensitaet und die kritischen Stroeme stimmen mit Modellrechnungen und Simulationen ueberein, die jedoch mit grossen Unsicherheiten behaftet sind. Das vorhergesagte Verhalten der Hochspannungsstroeme in Abhaengigkeit von der Strahlintensitaet oberhalb der kritischen Intensitaet konnte sehr genau bestaetigt werden. Die Teststrahldaten zeigen, dass das EMEC bis zu den hoechsten LHC-Luminositaeten arbeiten kann und ATLAS in dieser Detektorregion seine exzellenten Kalorimetereigenschaften beibehaelt
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Hellmich, Dennis [Verfasser]. "Measurement of the inclusive Z + bb cross section in pp-collisions at 7 TeV with ATLAS / Dennis Hellmich." Bonn : Universitäts- und Landesbibliothek Bonn, 2014. http://d-nb.info/1060787393/34.
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Ragoni, Simone. "Measurement of the Z and W production cross section in pp collisions at LHC using a bayesian approach." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amslaurea.unibo.it/11427/.
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L’obiettivo di tutto il mio lavoro è stato quello di misurare le sezioni d’urto
di produzione dei bosoni deboli W ± e Z nei loro decadimenti leptonici (e,
μ) coi dati raccolti dal rivelatore ATLAS a LHC con un’energia del centro
di massa di √s = 13 TeV relativi all’estate 2015. Gli eventi selezionati
sono gli stessi di quelli del recente articolo della Collaborazione ATLAS sullo stesso argomento, in modo anche da poter operare un confronto tra i risultati ottenuti. Confronto peraltro necessario, poichè i risultati sono stati ottenuti con due metodologie differenti: tradizionale (classica) per l’articolo,
bayesiana in questa tesi. L’approccio bayesiano permette di combinare i vari canali e di trattare gli effetti sistematici in modo del tutto naturale. I risultati ottenuti sono in ottimo accordo con le predizioni dello Standard Model e con quelli pubblicati da ATLAS.
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Larner, Aimee Bridget. "Measurement of the Z—>TlTh cross-section and search for the standard model vector boson fusion produced Higgs —>TlTh at ATLAS." Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:1b7174f0-802f-40ac-9ae9-bc0c589e4d6e.
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This thesis presents a cross-section measurement of the Z -+ TeTh process performed using the ATLAS detector at the Large Hadron Collider at CERN. The data used were collected at a centre-of-mass energy of 7 TeV during 2010 and corresponds to an integrated luminosity of 36 pb-I. This measurement uses the final state where one T lepton decays leptonically, to an electron or muon, plus neutrinos, and the other T lepton decays hadronically. The "(* / Z -+ a, It and di-boson background processes are estimated using Monte Carlo simulation, the W -+ TV Monte Carlo background prediction is estimated using a semi data-driven method. The multijet background is estimated with a fully data-driven 'ABCD' method using three exclusive control regions built by inverting uncorrelated requirements on the isolation of the electron or muon and the product of the electric charge of the identified electron or muon and hadronically decayed T lepton. The measured cross-sections in each channel are corrected for the individual branching ratios and yield the total cross-section a(Z -+ TT, minv 66 - 116 GeV) = 1142 ± 135.5(stat.) ± 206.2(syst.) ± 40. 19(1umi.) ± 3.6(theo.) pb for the electron channel and a(Z -+ TT, minv 66 - 116 GeV) = 857.6 ± 81.4(stat.) ± 132.5(syst.) ± 30.19(lumi.) ± 2.8(theo.) pb for the muon channel, where the invariant mass of the Z boson is between 66 and 116 GeV. These are in good agreement with the theoretical prediction of960 ± 49.5 pb. Performing a measurement of a well-known Standard Model process using the ATLAS de- tector in this new high energy regime is essential for validating the T lepton identification in particular, which is essential for any new physics search such as H -+ TeTh' A cut-based analysis for the Vector Boson Fusion produced Higgs boson decaying to two T leptons channel is introduced and the possibility of using the more complex analysis technique, the Matrix Element method, to increase sensitivity is discussed.
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Doan, Thi Kieu Oanh. "Mesure de la section efficace différentielle de production du boson Z se désintégrant en paires électron-position, dans l'expérience ATLAS." Phd thesis, Université de Grenoble, 2012. http://tel.archives-ouvertes.fr/tel-00846877.
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La première mesure du spectre en phi*_eta du boson Z à 7 TeV a été réalisée dans cette thèse. Cette variable permet de sonder la dynamique de production des Z de façon fine. L'échantillon complet des données enregistrées par ATLAS en 2011 a été utilisé ce qui correspond à 4.7/fb de luminosité intégrée. Les résultats de cette mesure sont publiés dans la Ref. [18] fondé sur la note interne Ref. [69]. La section efficace différentielle de Z->ee en fonction phi*_eta a été mesurée et comparée aux calculs perturbatifs à ordre fixé, avec/sans resommation pour la région des petits phi*_eta. Le code RESBOS fournit la meilleure description des données, cependant il est incapable de reproduire, à mieux de 4%, la forme détaillée de la section efficace mesurée. La section efficace différentielle a également été comparée aux prédictions de différents générateurs Monte Carlo interfacés avec un algorithme de parton shower. Les meilleures descriptions du spectre en phi*_eta mesuré sont données par les générateurs SHERPA et POWHEG+PYTHIA8. La mesure précise de la section efficace différentielle en phi*_eta fournit des informations précieuses pour l'ajustement des codes Monte Carlo. La précision expérimentale typique de cette mesure (~0.5%) est dix fois meilleure que la précision des calculs théoriques et elle est donc aussi précieuse pour contraindre la théorie. La mesure du spectre en ptZ a également été faite pour quantifier l'incertitude systématique de cette mesure en utilisant la grande statistique de l'échantillon de données. Cela permet de comparer deux mesures qui traitent de l'impulsion transverse du boson Z. Dans la plupart du domaine en phi*_eta l'incertitude systématique de la mesure de ptZ est deux fois plus grande que celle de la mesure de phi*_eta. Cette comparaison confirme l'intérêt de la variable phi*_eta. Les résultats présentés dans cette thèse ont beaucoup d'implications pour les études futures. Ajustant les générateurs Monte Carlo en utilisant les résultats de la mesure précise du spectre en phi*_eta minimisera l'incertitude sur leurs paramètres. Une mesure de la section efficace doublement différentielle en ptZ et phi*_eta est intéressante pour mieux comprendre la corrélation entre ces deux variables. La mesure précise du spectre en ptZ utilisant la variable phi*_eta peut être appliquée au spectre en ptW et on sait que des mesures plus fines du ptW sont importante pour une détermination précise de la masse du boson W. De plus, une compréhension précise du spectre en ptZ est importante pour comprendre les propriétés cinématiques de la production du boson de Higgs.
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LUCOTTE, Arnaud. "Contraintes du Modele standard par les mesures de sections efficaces et asymetries Z-->ffbar avec le detecteur ALEPH au LEP." Phd thesis, Université Claude Bernard - Lyon I, 1996. http://tel.archives-ouvertes.fr/tel-00002529.
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Mon travail concerne le test du modele standard par la determination précise des paramètres décrivant la resonance du Z: $M_Z$, $\Gamma_Z$, $\sigma_{had}^0$ et $R_{had}$, à partir des sections efficaces fermioniques mesurées par l'expérience Aleph sur les données accumulées de 1989 à 1994. La premiere partie rappelle la définition des observables utilisees dans la description des désintégrations $e^+e^-$. La deuxieme presente le collisionneur LEP et les méthodes employees pour la determination de l'energie des faisceaux, parametre constituant la source principale d'incertitude dans la connaissance de $M_Z$ et $\Gamma_Z$. La troisieme partie presente le cadre de l'experience Aleph et la mesure de luminosité qui y est effectuee. Puis sont décrits la sélection des désintégrations hadroniques du $Z$ et le travail effectue sur l'amélioration des incertitudes systématiques. Ce dernier conduit à une mesure de la section efficace au niveau de 1 pour mille. Les sections efficaces leptoniques mesurées à Aleph y sont également reportées. Les paramètres de la résonance du $Z$ sont alors dérivés. Un accord remarquable de ces résultats avec les valeurs prédites par le modèle standard des interactions électrofaibles est obtenu. L'interprétation de ces mesures dans le cadre de ce modèle permet alors la détermination du nombre de familles de neutrinos légers et l'établissement de contraintes sur la masse du quark top manquant, en bon accord avec les mesures directes de Fermilab.
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Ortolan, Lorenzo. "Measurement of Z/γ*+b—jet production cross section in pp collisions at √s= 1:96 TeV with the CDF detector." Doctoral thesis, Universitat Autònoma de Barcelona, 2012. http://hdl.handle.net/10803/284030.
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Procesos en colisionadores hadronicos, como por ejemplo la producción de jets, pueden describirse con la teoría de la Cromodinámica Quántica (QCD). Descripciones precisas de procesos de producción de jets asociadas con un vector bosón tienen hoy en día gran relevancia ya que estos representan un fondo irreducible para otros procesos del Modelo Estándar y para la búsqueda de nueva física. El estudio experimental de la producción de b jets asociada con un bosón Z es crucial por varios motivos. Por un lado, este constituye la fuente de fondo más importante para la búsqueda del bosón de Higgs ligero que decae en una pareja de quarks b bbar y que es producido junto a un bosón Z. Este canal es uno de lo más importantes en la búsqueda del Higgs en el Tevatron en particular después que los nuevos resultados experimentales excluyeran la región de alta masa. Por otro lado, estados finales constituidos por b jets y un bosón Z son también fuente de contaminación en la búsqueda de nueva física como por ejemplo de supersimetria donde está permitido un acoplamiento fuerte del Higgs supersimétrico y el quark bottom.
La medida de la sección eficaz de producción de b jets junto a un bosón Z ha sido realizada previamente en el Tevatron por los experimentos CDF and D0 y en LHC por CMS y ATLAS. En particular la medida de CDF se realizó utilizando solo 2 fb-1 de datos y por tanto resultó limitada por la incertidumbre estadística. Esta tesis doctoral presenta una nueva medida de la sección eficaz de Z/γ* +b jets utilizando todos los datos adquiridos por CDF durante el Run II.
Los bosones Z/γ* son seleccionados vía su decaimiento a dos muones o dos electrones y pidiendo su masa se encuentre entre 66 y 116 GeV/c2, mientras los jets se han reconstruido con el algoritmo de MidPoint con un radio de 0.7 y requiriendo que sean centrales y de alto momento transverso.
La sección eficaz se presenta como cociente respecto a la sección eficaz inclusiva de Z/γ y de Z/γ+jet y los resultados son comparados con predicciones al orden más bajo en teoría de perturbaciones (LO) más parton showers y del siguiente nivel (NLO) corregidas por los efectos no perturbativos como la hadronización y los relacionados con interacciones secundarias que no forman parte de la interacción fuerte. También se ha medido la sección eficaz diferencial en función del momento transverso y de la posición angular del jet y se han comparado con la predicción a NLO calculada en diversas escalas de energía y para distintas PDF .Processes at hadron colliders, such as the production of jets, are described by the Quantum Chromodynamics theory (QCD). Precise descriptions of processes involving jets in association with a vector boson have nowadays large relevance as they represent irreducible background to other Standard Model (SM) processes and searches for new physics. The experimental study and understanding of the b-jet production in association with a Z boson are crucial for many reasons. For one side, it is the most important background for a light Higgs boson decaying into a bottom-antibottom quark pair and produced in the ZH mode. This is one of the most promising channels for the Higgs search at Tevatron in particular since the latest results have excluded the high mass region (MH > 127 GeV/c2 ). For another side the signature of b-jets and a Z boson is also background to new physics searches, such as supersymmetry, where a large coupling of the Higgs boson to bottom quarks is allowed. The production cross section measurement of b-jets in events with a Z boson has already been performed at hadron colliders, at the Tevatron by CDF and D0 experiments and are now pursued at the LHC by ATLAS and CMS. In particular the CDF measurement was performed with only 2 fb-1 and was limited by the statistical uncertainty. This PhD thesis presents a new measurement of the Z/γ*+b-jet production cross section using the complete dataset collected by CDF during the Run II. Z/γ* bosons are selected in the electron and muon decay modes and are required to have 66 < MZ < 116 GeV/c2 while jets, reconstructed with the MidPoint algorithm, have to be central (|Y| < 1.5) with pT > 20 GeV/c . The per jet cross section is measured with respect to the Z/γ* inclusive and the Z/γ*+jets cross sections. Results are compared to leading order (LO) event generator plus parton shower and next-to-leading order (NLO) predictions corrected for non perturbative effects such as hadronization and underlying event. Differential distributions as a function of jet transverse moment and jet rapidity are also presented together with the comparison to NLO pQCD predictions for different renormalization and factorization scales and various PDF sets.
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Lomič, Jiří. "Smyková pevnost prvků stavebních konstrukcí z textilního betonu." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2017. http://www.nusl.cz/ntk/nusl-393995.
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The scope of the presented Diploma thesis was the establishment of calculation model for shear design of textile reinforced concrete members with rectangular cross-section. To accomplish this task, it was necessary to acquire the knowledge of the principles of shear design for steel reinforced concrete and existing design methods for textile reinforced concrete. Based on these principles, an experiment was designed as 3-point bending test to obtain values of acting shear force in textile reinforced concrete beams. These beams were filled with textile reinforcement made of carbon and alkali resistant glass and cast in the laboratory of the Solidian Company. An important factor for the experiment design was the a/d ratio which was constant for all tested beams. The value of acting shear force as well as of concrete compressive strength was obtained from each experiment. These values were used for the optimization of mathematical equation for the shear design of textile reinforced concrete members with rectangular cross-section. This equation was first analyzed to gain the knowledge of every influential factor. After, the coefficient CRm,c was determined from the experimental data using the methods of optimization. The problem statement resulted in the formula for shear design of textile reinforced concrete members with rectangular cross-section which may be applied with respect to the conditions of usability of the shear model.
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Le, Ménédeu Eve. "Etude des performances du spectromètre à muons du détecteur Atlas au LHC, des cosmiques aux collisions : mesure de la section efficace de production des dibosons WZ." Paris 6, 2011. http://www.theses.fr/2011PA066335.
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Arnaez, Olivier. "Préparation de la mesure de la section efficace inclusive du Z -> e+e- dans ATLAS : étude des premières données avec le calorimètre électromagnétique." Chambéry, 2010. http://www.theses.fr/2010CHAMS018.
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Les collisions proton-proton à une énergie dans le centre de masse de 7 TeV au LHC produiront des basons Z en grande quantité dont la mesure de la section efficace de production constitue un test du Modèle Standard. Après avoir décrit le contexte théorique et procédé à une description du détecteur ATLAS et des outils de simulation et d'analyse, une partie de cette thèse est consacrée à l'exploitation des événements cosmiques enregistrés dans la phase de préparation aux collisions afin de valider la simulation des formes de gerbes électromagnétiques dans un contexte proche de celui des collisions. Une deuxième partie de la thèse s'attache à la description des éléments clefs intervenant dans la mesure de la section efficace. Des critères de sélection utilisant des variables d'isolation, alternatifs à la sélection standard, ont été étudiés et ont mené à l'observation des premiers candidats Z->e+e- dans ATLAS. Enfin, les principales sources d'erreurs systématiques intervenant dans la mesure de section efficace ont été étudiées. Il s'agit des incertitudes liées d'une part à l'efficacité de sélection des électrons et d'autre part à l'efficacité géométrique du détecteurProton-proton collisions at 7 TeV in the center-of-mass at the LHC Will produce many Z-bosons for which the measurement of the production cross-section is a test of the Standard Model. After a description of the theoritical context and of the ATLAS detector, simulation and analysés tools, a part of this thesis is dedicated to the use of cosmic rays events recorded during the commissioning in order to validate the simulation of the electromagnetic shower shapes. A second part gives a description of the keys stops for the cross-section measurements. Selection criteria based on isolation variables -alternatively to the standard selection- have been studied and used to observe the first Z->e+e- in ATLAS. Finally, the main sources of systematic errors implied *n the cross-section measurement have been studied, specifically those linked to the electron selection efficiencies and the geometrical acceptance of the detector
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Lilley, Joseph Neil. "Z + γ differential cross section measurements and the digital timing calibration of the level-1 calorimeter trigger cluster processor system in ATLAS." Thesis, University of Birmingham, 2011. http://etheses.bham.ac.uk//id/eprint/1612/.
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This thesis investigates the reconstruction of Z(→ee)γ events with the ATLAS detector at the LHC. The capabilities of the detector are explored for the initial run scenario with a proton-proton centre of mass collision energy of √s = 7TeV, and an integrated luminosity of \(\char{cmsy10}{0x4C}\) = 1 fb⁻¹. Monte Carlo simulations are used to predict the expected precision of a differential cross-section measurement for initial state radiation Z + γ events, both with respect to the transverse momentum of the photon, p_T(γ), and the three body eeγ invariant mass. A bin-by-bin correction is used to account for the signal selection efficiency and purity, and to correct the measured (simulated) distribution back to the theoretical prediction. The main backgrounds are found to be from the final state radiation Z + γ process, and from jets faking photons in Z → ee events. The possible QCD multijet background is studied using a fake-rate method, and found to be negligible for the particle identification cuts used in the analysis. The main systematic uncertainties on the differential cross-section measurements are explored with Monte Carlo simulations, and found to be of a similar scale to the statistical errors for the chosen distribution binning. The three body eeγ invariant mass distribution was then used as the basis of an exclusion study on new particles decaying to the Z(ee)γ final state. Under the assumption that the measured data agrees with the Standard Model prediction, exclusion limits were placed at 95% confidence level on the cross-section times branching ratio for a new scalar (modelled by SM Higgs process), or vector (based on a low-scale technicolor process) particle hypothesis, for particles in the mass range 200 to 900GeV. Limits of the order \(\char{cmsy10}{0x4f}\)(0.01) - \(\char{cmsy10}{0x4f}\)(0.1) pb on the cross section times branching ratios are predicted, which would improve on the equivalent limits previously calculated by the DØ experiment at the Tevatron collider, albeit in a different √s region, where cross-sections will generally be higher for new massive particles. In addition to the Zγ measurements, a digital timing calibration procedure was developed for the Cluster Processor (CP) subsystem of the level-1 calorimeter trigger. This work was essential to providing a repeatable and robust mechanism for timing in the digital processing in the CP system, a necessary ingredient for a robust and reliable trigger system; a pre-requisite of any physics analysis. This calibration procedure is described here.
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Martinez, Homero. "Measurement of the Z boson differential cross-section in transverse momentum in the electron-positron channel with the ATLAS detector at LHC." Phd thesis, Université Paris-Diderot - Paris VII, 2013. http://tel.archives-ouvertes.fr/tel-00952940.
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Ce travail présente la mesure de la section efficace différentielle du boson Z en impulsion transverse (ptz), dans le canal de désintégration electron-positron, avec le détecteur ATLAS au LHC. La mesure utilise 4.64 inverse fb de données de collisions proton-proton, prises en 2011 avec une énergie du centre de masse de 7 TeV. Le résultat est combiné avec une mesure indépendante faite dans le canal muon-antimuon. La mesure est faite jusqu'à ptz = 800 GeV, et a une incertitude typique de 0.5 % pour ptz < 60 GeV, atteignant jusqu'à 5 % vers la fin du spectre. La mesure est comparée avec modèles théoriques et prédictions des générateurs Monte Carlo.
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Gilbert, Andrew. "Searches for neutral Higgs bosons decaying to tau pairs and measurement of the Z+b-jet cross section with the CMS detector." Thesis, Imperial College London, 2014. http://hdl.handle.net/10044/1/23290.
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The Compact Muon Solenoid (CMS) is a general-purpose particle detector at the CERN Large Hadron Collider. It is designed to search for the Higgs boson and evidence of new physics and to test the predictions of the standard model (SM) at the TeV scale. This thesis describes analyses of proton-proton collision data recorded by CMS during 2011 and 2012. A study of Z boson production in association with b jets, using 2.1 fb^{-1} of data recorded at a centre-of-mass energy of 7 TeV, is presented. The cross sections for production with exactly one, or at least two, b jets are measured, and the event kinematics are compared to the predictions of the madgraph event generator interfaced with pythia for hadronisation and parton showering. Searches for neutral Higgs bosons decaying to tau pairs are also presented. One search is in the context of the SM Higgs boson, for mass hypotheses in the range 90-150 GeV, and the other in the minimal supersymmetric standard model (MSSM), in which three neutral Higgs bosons are predicted and the search range is from 90 GeV to 1 TeV. Both searches use 4.9 fb-1 of data collected at 7 TeV and 19.7 fb^{-1} collected at 8 TeV. In the SM search an excess of events above the background expectation is observed and found to be compatible with the SM expectation for the 125 GeV Higgs boson. The observed (expected) local significance of this excess is 3.0 (3.1) standard deviations at 125 GeV. No significant excess is observed in the MSSM search. Upper limits at the 95% confidence level are determined, both in the m_A-tan(beta) parameter space of the m_h^max scenario and on the production cross sections in a model-independent interpretation.
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Svintradze, Irakli. "Diboson physics with CMS detector." Diss., Kansas State University, 2013. http://hdl.handle.net/2097/15782.
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Doctor of PhilosophyDepartment of Physics
Yurii Maravin
In this dissertation, you will find a study of di-boson production in pp collision with the Compact Muon Solenoid (CMS) detector at Large Hadron Collider (LHC). A study of Z+gamma process is performed on the data collected by the CMS during 2011 and corresponding to integrated luminosity L= 5 fb[superscript]-1. The study consists of two parts: cross section measurement and setting the limits on anomalous trilinear gauge couplings (aTGC) between a Z boson and a photon. The measured cross-section of Z+gamma agrees within the uncertainties with the standard model predicted cross section at next to leading order. Having found no excess in cross section measurement, we set the 95% con fidence level (C.L.) limit on aTGC. Another study discussed is a study of a low-scale walking Technicolor model with rho[subscript]T and a[subscript]T production in the fully leptonic fi nal state at 95% C.L. in proton-proton collisions at center of mass energy 10 TeV scenario using Monte Carlo simulation. We conclude that such processes can be excluded with 366 pb[superscript]-1 of data for rho[superscript]T masses up to 400 GeV and the observation would require 2.8 fb[superscript]-1 of data with 5 sigma precision.
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Steinbach, Peter. "A Cross Section Measurement Of Events With Two Muons At The $Z^{0}$ Resonance And At Least One Heavy Flavour Jet At The ATLAS Experiment Of The Large Hadron Collider." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-95532.
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In 2010, the Large Hadron Collider (\\lhc{}) at the European Organisation for Nuclear Research (CERN) near Geneva (Switzerland) came into full operation providing proton-proton collisions at a centre-of-mass energy of $\\sqrt{s} = \\unit[7]{TeV}$. \\lhc{} data may allow the observation of the Higgs boson, the last unknown building block of the standard model of particle physics (SM). Di-muon final states containing heavy flavour jets pose an irreducible background for searches of the Higgs boson as predicted the SM or theories beyond. They also provide a unique testbed for tests of perturbative Quantum Chromo-Dynamics (pQCD). This thesis provides a measurement of the cross section of events with one di-muon pair with an invariant mass in the \\Z{} mass region and at least one heavy flavour jet. Studies on acceptance and systematic effects of the experimental setup are presented as well as a comparison to theoretical predictions. The total inclusive cross section of \\zbFS{} events was observed as $\\sigma(\\mu^{+}\\mu^{-}+b+X) = \\unit[(4.15 ^{+0.97}_{-0.89} (stat.) ^{+0.45}_{-0.53} (syst.))]{pb} $ from the equivalent of $\\unit[36]{pb^{-1}}$ of data. Agreement with pQCD predictions at next-to leading order (NLO) is found while tensions with leading order (LO) predictions are observed. Further, the cross-section ratio \\RwZ{} with events containing two muons and at least one jet of any origin was measured to $\\mathcal{R} = \\unit[4.6 ^{+1.4}_{-1.2} (stat.) \\pm 0.5 (syst.)]{\\%}$. This is found to agree with NLO and LO calculations within known uncertainties.
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Bundock, Aaron Colin. "Measurement of the cross-section for b-jets produced in association with a Z boson at sqrt(s) = 7 TeV with the ATLAS detector." Thesis, University of Liverpool, 2013. http://livrepository.liverpool.ac.uk/15373/.
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In this thesis, 4.7 fb^(-1) of data taken in 2011 by the ATLAS Experiment of proton-proton collisions at sqrt(s) = 7 TeV delivered by the Large Hadron Collider at CERN is used to measure the integrated and differential cross sections for the production of electroweak Z bosons in associaton with b quark jets. Z bosons are identified by reconstructing the electron and muon decay modes, and the fraction of b quark jets in the Z sample is estimated by fitting the neural network output of a specialised heavy flavour tagging algorithm in data with light + charm and bottom flavour templates derived from Monte Carlo simulation. The integrated Z + b jet cross section is measured to be 5.04 +- 0.17 stat +- 0.83 syst pb. The ratio of the integrated Z + b jet cross section to the inclusive Z production cross section is measured to be (5.26 +- 0.18 stat +- 0.89 syst) 10^(-3). The integrated Z +b jet cross section is also measured differentially in bins of b jet transverse energy, b jet rapidity, and Z boson transverse momentum. These measurements are compared to predictions from leading order Monte Carlo generators and next-to-leading-order QCD calculations. Also contained within this thesis are contributions to the commissioning of the ATLAS detector with early data, and studies produced for the calibration of software algorithms used in the tagging of heavy flavour jets. The resolution of the ATLAS inner detector is measured using data recorded by ATLAS in 2009. Systematic effects resulting in discrepancies between the efficiency to identify heavy flavour jets in data and simulation are measured using 2010 ATLAS data.
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Taouri, Abdelillah. "Études de l'absorption à deux photons dans des matériaux organiques à l'aide de la technique dite de la lentille thermique." Phd thesis, Université d'Angers, 2009. http://tel.archives-ouvertes.fr/tel-00485310.
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Ce travail concerne la mise en oeuvre de la technique de la « lentille thermique » pour l'étude des phénomènes d'absorptions multiphotoniques dans les matériaux organiques. La technique de la lentille thermique utilisée ici, est dans son principe une technique pompe-sonde où le faisceau pompe provient d'un laser pulsé (25ps, 532nm ou 1064nm) tandis que le faisceau sonde est issu d'un laser continu (He-Ne : 632nm). Cette technique s'apparente aussi à la technique de z-scan dans la mesure où l'échantillon est déplacé de part et d'autre du point focal d'une lentille convergente disposée sur le trajet du faisceau pompe. Selon le rapport des diamètres des faisceaux pompe et sonde, on distingue deux variantes principales de la technique de la lentille thermique en régime pulsé : la variante dite en « modes accordés » (les diamètres des deux faisceaux sont identiques) et la variante en « modes désaccordés » (les diamètres des deux faisceaux sont différents). Pour des raisons de simplicité de mise en oeuvre et de sensibilité, nous avons choisi la variante en modes désaccordés. Cette variante de la technique de la lentille thermique, ayant été peu utilisée jusque là, a été utilisée pour mesurer le coefficient et la section efficace de l'absorption à deux photons dans différents matériaux organiques. Ces résultats sont comparés à d'autres mesures provenant de technique de mesure plus connue comme « transmission non linéaire » ou la technique de z-scan.
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Sandhoff, Marisa [Verfasser]. "Prospects of a cross section ratio measurement of W and Z events as a function of the jet multiplicity with early ATLAS data / Marisa Sandhoff." Wuppertal : Universitätsbibliothek Wuppertal, 2010. http://d-nb.info/1006174206/34.
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Kagan, Michael Aaron. "Measurement of the \(W^{\pm}Z\) Production Cross Section and Limits on Anomalous Triple Gauge Couplings at \(\sqrt s = 7 TeV\) using the ATLAS detector." Thesis, Harvard University, 2012. http://dissertations.umi.com/gsas.harvard:10380.
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This dissertation presents a measurement of the \(W^{\pm}Z\) production cross section and limits on anomalous triple gauge couplings in proton-proton collisions at a center of mass energy of 7 TeV using data produced by LHC collisions and acquired by the ATLAS detector in 2011. The measurement and limits probe the electroweak sector of the Standard Model at high energies and allow for generic tests for new physics that could be present at high energy scales. This analysis is also useful for understanding the ATLAS detector response in the presence of multi-lepton signatures. The dataset used corresponds to an integrated luminosity of \(1.02 fb^{−1}\). The measurement relies on the leptonic decay modes of the W and Z, resulting in final states with electrons, muons, and missing energy. Events are selected by requiring three high momentum leptons, a large missing transverse energy, a Z candidate (reconstructed from two of the leptons) with a mass consistent with the Z pole mass, and a W candidate (reconstructed from the third lepton and the missing energy) with a large transverse mass. The backgrounds to the \(W^{\pm}Z\) process are estimated using Monte Carlo simulations and Data-Driven techniques. A total of 71 \(W^{\pm}Z\) candidate events are observed in data, with 50.3 signal and 12.1 background events expected. The production cross section is extracted from these events using a maximum likelihood method, and is found to be in good agreement with the Standard Model expectation. Limits at the 95% confidence interval on anomalous triple gauge couplings are extracted from the observed event yields using a frequentist limit setting approach.Physics
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Burian, Jiří. "Experimentální a výpočetní výzkum vlastností solí pro jaderné reaktory typu MSR z pohledu jaderných dat." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2021. http://www.nusl.cz/ntk/nusl-442467.
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Nowadays there is research into molten salt reactors. The use of chlorine-based salts, which would be more available than known fluoride salts, is envisaged. The subject of research is not only the chemical and physical properties of chloride salts, but also their behavior in the neutron field and the influence of neutron balance inside the reactor. Many properties can also be determined using calculations that draw information from scientific nuclear libraries (endf). The purpose of this work is to compare important nuclear libraries with each other, and also to compare the reaction rates calculated from the library data with the reaction rates obtained by self-measurement. The preview will include a description of the necessary activities associated with the preparation of measurements, instructions for compiling the computer program NJOY and the process of the measurement itself. At the end of the work will be summarized the results and statements of which nuclear library is the closest in its values to the results of experiments.
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Kormoll, Kathrin [Verfasser], Michael [Akademischer Betreuer] Kobel, and Dominik [Akademischer Betreuer] Stöckinger. "Mass reconstruction techniques and cross section measurement for Z→ττ→eμ+4υ with the ATLAS experiment / Kathrin Kormoll. Gutachter: Michael Kobel ; Dominik Stöckinger. Betreuer: Michael Kobel." Dresden : Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2013. http://d-nb.info/1068152001/34.
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Berger, Thomas [Verfasser], and G. [Akademischer Betreuer] Quast. "Jet energy calibration and triple differential inclusive cross section measurements with Z (→μμ) + jet events at 13 TeV recorded by the CMS detector / Thomas Berger ; Betreuer: G. Quast." Karlsruhe : KIT-Bibliothek, 2019. http://d-nb.info/120207670X/34.
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Seifert, Frank [Verfasser], Arno [Akademischer Betreuer] Straessner, and Arnulf [Akademischer Betreuer] Quadt. "Z to tau tau Cross Section Measurement and Liquid-Argon Calorimeter Performance at High Rates at the ATLAS Experiment / Frank Seifert. Gutachter: Arno Straessner ; Arnulf Quadt. Betreuer: Arno Straessner." Dresden : Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2013. http://d-nb.info/1068443820/34.
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Evangelakou, Despoina [Verfasser], Arnulf [Akademischer Betreuer] Quadt, and Ariane [Akademischer Betreuer] Frey. "Z → tau h tau Cross Section Measurement and tau tau Mass Reconstruction with the ATLAS Detector at the LHC / Despoina Evangelakou. Gutachter: Arnulf Quadt ; Ariane Frey. Betreuer: Arnulf Quadt." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2012. http://d-nb.info/1043610294/34.
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Jin, Daming. "Off line computer analysis of total cross section for proton nucleus collisions at 400 Gev/C proton beam energy on a VAX system and conversion to a Z-386 PC system." Virtual Press, 1991. http://liblink.bsu.edu/uhtbin/catkey/834638.
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A large MULANA based analysis package, written in FORTRAN, for computing the cross section for proton - nucleus collisions at 400 GeV/c momentum from data taken in experiment E609 at FNAL, was implemented on a Z-386, 16 MHz microcomputer workstation featuring an 80 Mbyte hard drive, and a three Gbyte 8-mm Exebyte tape drive, based in the Ball State High Energy Physics Laboratory, in a feasibility study of conducting such analysis on a workstation as a viable alternative and/or adjunct to the Ball State University VAX system. One of 40 large 1600 bpi 9-track data tapes from Experiment 609 provided the data file for the computation. The analysis package was first run on the VAX system. Special problems solved in connection with using the software package included converting the large data file to a suitable form for use at the workstation, transporting that file from the VAX to the workstation, modifying the VAX FORTRAN software package for implementation in the OS/2 workstation operating system environment, and graphical exposition of the results. With the results of conducting the analysis on the VAX system serving as a benchmark, it was determined first that the quantitative analysis results were identical, second, that computing times were similar, and third that the workstation provided unique conveniences. Overall, the results showed that the workstation is a reasonable alternative to using the VAX for High Energy Physics analysis work but also suggest the attractiveness of using similar but faster workstations in the near future.Department of Physics and Astronomy
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Pernie, Luca. "Measurement of the Z boson pair-production cross section in proton-proton collisions at 7 and 8 TeV, and ECAL timing studies for the phase-2 upgrade of the CMS experiment." Doctoral thesis, Universite Libre de Bruxelles, 2015. https://dipot.ulb.ac.be/dspace/bitstream/2013/216690/3/tdmPernie.pdf.
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The Large Hadron Collider (LHC) marks a new era for particle physics. Thanks to the very high energy of the proton beams, and to the large amount of data collected in years 2010-12, the physicists at CERN can test the standard model (SM) consistency, can explore the scalar sector, and search for any hint of new physics. A measurement of the Z boson pair production cross section using proton-proton collisions at 7 and 8 TeV center-of-mass energy, recorded by the CMS (Compact Muon Solenoid) experiment is presented. Diboson production at the LHC is of particular interest: it validates rare SM processes never tested before with high accuracy, it probes the electroweak boson self-interactions, and it constitutes a background for many physics searches such as the searches for the Higgs boson or supersymmetry. The ZZ production cross section is measured via the decay channel ZZ to 2l2v. The data used for the analysis have been recorded in years 2011 and 2012 by CMS and correspond to an integrated luminosity of about 5.1 fb-1 at 7 TeV and 19.6 fb-1 at 8 TeV. The data are selected requiring the presence of two isolated leptons (electrons or muons) of the same flavor with high transverse momentum (pT). In addition, events containing jets or additional leptons are vetoed, and it is applied a selection based on the dilepton pT, on the dilepton invariant mass, and on the transverse momentum imbalance (Emiss). The main SM backgrounds for this analysis are the Z/gamma+jet (Drell-Yan) process, the fully leptonic tt and single-top decay, and the WW and WZ diboson processes. The Z/gamma + jet process has no neutrinos in the final state, thus it has no large Emiss, but its cross section at the Z-peak is four orders of magnitude larger than the ZZ production. For this reason, even if the fraction of Z/gamma + jet events reconstructed with significant instrumental Emiss is not large, a high Emiss cut must be applied in order to improve the signal purity. High Emiss in Z/gamma + jet events is due to misreconstruction of physical objects, and to the additional energy deposits arising from the other proton-proton interactions occurring in the same bunch crossing (pileup). These effects are not well described in simulation, for this reason a high statistic control sample has to be used in order to model these tails from data. The fully leptonic tt, the single-top decay, and the WW process have been estimated in a control sample obtained requiring exactly one electron and one muon in the final state. The WZ process instead, has been estimated directly from the simulation. All the background shapes and normalizations are then constrained to data from a fit to the shape of a discriminating variable (e.g. Emiss), allowing only the ZZ signal normalization to freely vary. The selected data were also analyzed to search for anomalous triple gauge couplings (aTGC) involving the ZZ final state, and subsequently combined with the ZZ to 2l2l' final state data, to increase the sensitivity. In the absence of signs of new physics we set limits on the relevant aTGC parameters. Between 2023 and 2025, to extend its discovery potential and/or characterize any new signal possibly discovered, the LHC will increase its instantaneous luminosity by a factor of 10 beyond its design value. The increasing in luminosity will produce an average of 140 pileup interactions, this will represent an issue for the trigger and the reconstruction, degrading the jet and photon energy resolution and all the physic objects isolation quantities. In order to maintain full sensitivity, from low to high energy scales under severe pileup and radiation conditions, the L1 trigger, the tracker, the ECAL endcap and the HCAL, and the forward muon system will be upgraded. Moreover it will be fundamental to tag and remove the extra activity from PU interactions in order to correct the relevant variables measurements. The last part of the thesis will test the utility of timing in pileup mitigation and object reconstruction. Timing could be exploited for the association of photons, electrons and jets to their collision vertices, for particle identification, or to reject energy deposits coming from secondary vertices. A time measurement, extract from simulation, will be used in several reconstruction algorithms, showing improvements in particle reconstruction.Doctorat en Sciences
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Nagarkar, Advait Neel. "A measurement of the W±Z production cross section and limits on anomalous trilinear gauge couplings in proton-proton collisions at √s = 7 TeV using 4.64 fb-1 of data collected with the ATLAS detector." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1354723434.
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Fischer, Florian Christoph Maria [Verfasser], and Otmar [Akademischer Betreuer] Biebel. "Measurement of the production cross section of a top-antitop quark pair in association with a Z boson at √s = 13 TeV with the ATLAS detector / Florian Christoph Maria Fischer ; Betreuer: Otmar Biebel." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2020. http://d-nb.info/1232176303/34.
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Li, Xingguo. "Measurements of the φ∗η distribution of Z → µ+µ− events in pp¯ collisions at √s = 1.96 TeV and measurements of the isolated diphoton cross section in pp collisions at √s = 8 TeV." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/measurements-of-the-distribution-of-z---events-inpp-collisions-at-s--196-tevand-measurements-of-the-isolateddiphoton-cross-section-in-ppcollisions-at-s--8-tev(7eb9f1b2-e563-4f8d-8e73-f73d8104dc60).html.
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Two precision measurements have been performed using the large number of dileptonand diphoton events produced in pp¯ and pp collisions. A measurement of thedistribution of the kinematic variable φ∗ηin the Drell-Yan process is performed inbins of boson rapidity and invariant mass using 10.4 fb−1 data collected by the D0experiment with a centre-of-mass energy of 1.96 TeV in pp¯ collisions. φ∗η, definedin terms of lepton track directions, is well-measured and is sensitive to higher ordereffects in Quantum chromodynamics (QCD). Data are compared to predictions fromstate-of-the-art QCD Monte Carlo programs and are in good agreement. Measurementsof the production of prompt photon pairs are performed using 20.24 fb−1 datacollected by the ATLAS experiment at 8 TeV in pp collisions. QCD Monte Carloprograms including higher order effects are found to describe the data. In addition,a luminosity algorithm that renders its susceptibility to noise and inefficiency of certainmodules in the diamond beam monitor has been proposed and validated usingATLAS simulations.
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Capriotti, Daniele [Verfasser], Hubert [Akademischer Betreuer] Kroha, and Stefan [Akademischer Betreuer] Schönert. "Measurement of the Z → τ+τ- production cross section in proton-proton collisions at 7 TeV center-of-mass energy with the ATLAS detector / Daniele Capriotti. Gutachter: Stefan Schönert ; Hubert Kroha. Betreuer: Hubert Kroha." München : Universitätsbibliothek der TU München, 2012. http://d-nb.info/1024161609/34.
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Kühn, Susanne [Verfasser], and Karl [Akademischer Betreuer] Jakobs. "First measurement of the Z/gamma*->tautau cross section in proton-proton collisions at sqrt(s) = 7 TeV with the ATLAS experiment at the LHC = Erste Messung des Z/gamma*->tautau Wirkungsquerschnittes in Proton-Proton-Kollisionen bei einer Schwerpunktsenergie von sqrt(s)=7 TeV mit dem ATLAS-Experiment am LHC." Freiburg : Universität, 2012. http://d-nb.info/1123466831/34.
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Andriatis, Alexander. "Generator-level acceptance for the measurement of the inclusive cross section of W-boson and Z-boson production in pp collisions at [square root of] s = 5 TeV with the CMS detector at the LHC." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/115668.
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Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2018.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 39-42).
The inclusive cross section of vector boson production in proton-proton collisions is one of the key measurements for constraining the Standard Model and an important part of the physics program at the LHC. Measurement of the inclusive cross section requires calculating the detector acceptance of decay products. The acceptance of the CMS detector of leptonic decays of W and Z bosons produced in pp colisions at [square root of]s = 5 TeV is calculated using Monte Carlo event simulation. Statistical and systematic uncertainties on the acceptance measurement from PDF and a, uncertainty and higher-order correction are reported. The use of the calculated acceptance in combination with measurements of detector efficiency, luminosity, and particle counting to determine the inclusive cross section is outlined. A total integrated luminosity of 331.64 pb-1 from 2015 and 2017 CMS data at [square root of]s = 5 TeV is available for the calculation of the inclusive cross section.
by Alexander Andriatis
S.B.
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Fayolle, David. "Production de paires de Z et polarisation des W à LEP2 avec le détecteur ALEPH ou Prolégomènes à toute étude future sur les bosons de Jauge qui pourra se présenter comme exhaustive." Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2002. http://tel.archives-ouvertes.fr/tel-00001884.
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La phase LEP2, à des énergies supérieures au seuil de production des paires de W et de Z, a permis l'étude du secteur le moins contraint du Modèle Standard, le secteur des bosons de jauge.Le travail de cette thèse, en utilisant l'ensemble des données de LEP2 enregistrées par le détecteur ALEPH; consiste en trois mesures fortes sur la validité de ce Modèle Standard :
- La mesure de la section efficace ZZ à travers les cinq canaux visibles de désintégration de la paire de Z. La faible statistique associée à la production de paires de Z en fait un processus délicat à discrimer.
- La mesure des couplages anomaux neutres dans l'état final ZZ. Ces couplages sont interdits dans le Modèle Standard et leur présence serait signe d'une Physique Nouvelle. Leur extraction utilise l'information sur la section efficace et l'angle de production du Z.
- La mesure des états de polarisation longitudinal et transverse des bosons W à travers la production W+W- dans le canal semi-leptonique. L'extraction se fait à partir de la matrice densité de spin ce qui permet d'obtenir des résultats indépendants du modèle utilisé pour décrire le phénomène.
Les résultats obtenus dans ces trois domaines de mesure ne présentent pas de déviation significative par rapport aux prédictions du Modèle Standard.
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Steinbach, Peter [Verfasser], Michael [Akademischer Betreuer] Kobel, and Ulrich [Akademischer Betreuer] Husemann. "A Cross Section Measurement Of Events With Two Muons At The $Z^0}$ Resonance And At Least One Heavy Flavour Jet At The ATLAS Experiment Of The Large Hadron Collider / Peter Steinbach. Gutachter: Michael Kobel ; Ulrich Husemann. Betreuer: Michael Kobel." Dresden : Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2012. http://d-nb.info/1068443391/34.
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Schmitt, Sebastian [Verfasser], and André [Akademischer Betreuer] Schöning. "Measurement of the Inclusive pp->Z/gamma*->e+e- Cross Section at sqrt(s) = 7 TeV with the ATLAS Experiment and Design Studies for a First Level Track Trigger for the ATLAS Trigger Upgrade at the future High Luminosity LHC / Sebastian Schmitt ; Betreuer: André Schöning." Heidelberg : Universitätsbibliothek Heidelberg, 2013. http://d-nb.info/1177382881/34.
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Descos, Lucie, and Anna-Maria Gospic. "Attract and retain Generation Z in the white-collar business sector. : How to attract and retain Generation Z in the white-collar business sector?" Thesis, Högskolan i Jönköping, Internationella Handelshögskolan, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-44066.
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Problem Following the expanded competition when it comes to attraction and retention of skilled workers, hence white-collar workers, organizations need to better adapt to the rapid changes in the labor market. Due to the lack of knowledge about the recent Generation Z and their perceptions and values regarding work, the Person-Organization (P-O) fit has been applied in order to gain a deeper knowledge of what attracts and retains individuals of Generation Z, in order for companies to better meet their needs. Purpose Due to the lack of research done on Generation Z, the purpose of this study is to gain a greater understanding of the values and perceptions of Generation Z and how they operate in the white-collar business sector. Moreover, this creates a greater insight for organizations in order to help them better target the right talent pool and gain a greater understanding of Generation Z that has come to change the labor market. Method In order to gain a greater knowledge and insight about Generation Z, a qualitative study has been performed to better understand the perception of this Generation. In-depth interviews have been conducted with Generation Z that have or are currently operating in the white-collar business sector in order to meet the purpose of this study. Semi-structured interviews were conducted in order to allow for a fruitful discussion of their values and perceptions and the likely impacts they consider when joining an organization. Conclusion Generation Z indicated that certain aspects are to consider in the decision-making process of applying or taking a job. Indeed, their own values, beliefs and work-personal life matter to a great extent and is to be matched with the company. This study comes to the result of six determined factors influencing this decision-making process: small enterprises, flexibility trust and freedom, work/private life environmental factors, organizations values/ethics, do what they love, digital natives.
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Sauvan, Jean-Baptiste. "Z+jets au LHC : calibration des jets et mesure de sections efficaces avec le détecteur ATLAS." Phd thesis, Université Paris Sud - Paris XI, 2012. http://tel.archives-ouvertes.fr/tel-00747024.
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La recherche du boson de Higgs ainsi que celle de nouvelle physique auprès du LHC requiert une excellente compréhension des processus du Modèle Standard du fait de leurs signatures expérimentales similaires. La capacité de mesurer le plus précisément possible l'énergie des objets reconstruits dans les détecteurs est par ailleurs primordiale à la fois pour effectuer des mesures de précision et pour accroître la sensibilité des analyses à des signaux de physique au-delà du Modèle Standard. Les travaux présentés dans cette thèse s'attachent à ces deux points par l'étude d'événements contenant un ou plusieurs jets associés à un boson Z avec le détecteur ATLAS. D'une part, ces événements sont utilisés pour améliorer la calibration en énergie des jets de faible impulsion transverse, d'une importance capitale pour les analyses utilisant le dénombrement de jets ou leur veto. D'autre part la section efficace différentielle de production de ces événements est mesurée en fonction de nombreuses observables et comparée à diverses prédictions théoriques. Ces mesures pourront être utilisées pour améliorer les prédictions qui servent de modèles de bruit de fond dans des analyses sur le boson de Higgs et de recherche de physique au-delà du Modèle Standard.
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Kovalčík, Martin. "Financování projektů z fondů EU." Master's thesis, Vysoké učení technické v Brně. Fakulta podnikatelská, 2010. http://www.nusl.cz/ntk/nusl-222602.
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Projects finance by funds of European Union deals about possibilities and assessment of investments to the projects which bring the benefit to public sector at the level regions, but also as whole for society. On this account can be financed from means of company of EU. The aim diploma thesis is finding factural prospectus in select sector and choose variants of realization. On the basis ascertained records these variants analyze and financially valorize. The thesis will be resolved reconstruction project memorable buildings in the city center Bohumín, thus create new spaces for public library facilities and training center for commercial and non-commercial nature.