Investigation of spin correlations in top-pair production with the CMS detector at the LHC [Elektronische Ressource] / Martina Davids

Investigation ofSpin Correlations in Top-Pair Productionwith the CMS Detector at the LHCVon der Fakult¨at fur¨ Mathematik, Informatik und Naturwissenschaftender RWTH Aachen University zur Erlangung des akademischen Gradeseiner Doktorin der Naturwissenschaften genehmigte Dissertationvorgelegt vonDiplom-PhysikerinMartina Davidsaus T¨onisvorstBerichter: Univ.-Prof. Dr. rer. nat. Achim Stahl Dr. rer. nat. Werner BernreutherTag der mundlic¨ hen Prufung¨ : 25. Februar 2011Diese Dissertation ist auf den Internetseiten der Hochschulbibliothek online verfu¨gbar.AbstractIn spring 2010 the Large Hadron Collider (LHC) started its operation with a center-of-mass energy of 7TeV, that will be increased up to 14TeV in the following years.√33 −2 −1Considering a medium energy of s = 10TeV and a luminosity of L = 10 cm ssome million top quarks are produced per year. This offers the opportunity to inves-tigate spin-correlations between the top quarks from pair production. As the spin-configuration of the top-quark pair depends on the production mechanism, a mea-surement of such effects is a unique tool to study the contributions of the productionprocesses and spin effects. This allows to test the Standard Model.Thisthesisinvestigatesdileptonictop-pairdecaysattheCompactMuonSolenoidbasedon simulated events. A quantitative measure of spin correlations is the asymmetryA,that manifests itself in the angular distribution of the two leptons.