Observation of W tau-nu tau decays with the ATLAS experiment [Elektronische Ressource] / Guilherme Nunes Hanninger

Observ ation ofW!tn Deca ystwith the A TLAS Exp erimen tInaugural-DissertationzurErlangung der Doktorw urde¨derMathematisc h-Naturwissensc haftlic hen F akult at¨derRheinisc hen F riedric h-Wilhelms-Univ ersit at¨zu Bonnv orgelegt v onGuilherme Nunes HanningerausCuritiba - BrasilienBonn 2011Univ ersit at¨ BonnPh ysikalisc hes InstitutObserv ation of W !tn Deca ystwith the A TLAS Exp erimen tGuilherme Nunes HanningerDieser F orsc h ungsb eric h t wurde als Dissertation v on derMathematisc h-Naturwissensc haftlic hen-F akult at¨ der Univ ersit at¨ Bonn angenommenund ist auf der ULB Bonn http://hss.ulb.uni- bonn.de/diss_onlineelektronisc h publiziert.Referen t: Prof. Dr. Norb ert W ermesK oreferen t: Prof. Dr. Ian C. Bro c kAngenommen am: 22.02.2011T ag der Promotion: 29.04.2011AbstractPh ysics studies of pro cesses with t leptons in the final state, while c hallenging athadron colliders, are of great imp ortance at the LHC. Thet leptons pro vide imp ortan tsignatures in searc hes for the Higgs b oson as w ell as for new ph ysics in a wide rangeof theoretical mo dels. Deca ys of Standar d Mo del particles to t leptons, in particularZ!tt andW!tn , are imp ortan t bac kground pro cesses in those searc hes and theirtcross sections need to b e measured first. This thesis rep orts the first observ ation ofW!tn deca ys and of hadronically deca ying t leptons with the A TLAS exp erimen ttat the LHC.