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Measurement of Neutral Current Drell-Yan production using ATLAS data collected at $\sqrt{s}=8$ TeV

This dissertation presents measurements of the $pp\rightarrow Z/\gamma^* \rightarrow e^+e^-+X$ production cross-section and of the Forward-Backward asymmetry, $A_{FB}$, of dielectron pairs with the ATLAS experiment at the Large Hadron Collider. Both measurements use the dataset collected in 2012 a...

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Detalles Bibliográficos
Autor principal: Yatsenko, Elena
Lenguaje:eng
Publicado: 2015
Materias:
Acceso en línea:http://cds.cern.ch/record/2041829
Descripción
Sumario:This dissertation presents measurements of the $pp\rightarrow Z/\gamma^* \rightarrow e^+e^-+X$ production cross-section and of the Forward-Backward asymmetry, $A_{FB}$, of dielectron pairs with the ATLAS experiment at the Large Hadron Collider. Both measurements use the dataset collected in 2012 at a center-of-mass energy of $\sqrt{s}=8$ TeV corresponding to an integrated luminosity of 20.1 $\text{fb}^{-1}$. The cross-section is measured single- and triple-differentially as a function of the rapidity, invariant mass and scattering angle of the dielectron pairs. The Forward-Backward asymmetry is measured double-differentially in bins of the dielectron invariant mass and rapidity. The study is performed with one of the final-state electrons detected in the forward calorimeter which allows large rapidities and scattering angles to be probed. The $pp\rightarrow Z/\gamma^* \rightarrow e^+e^-+X$ process is a rich source of information on electroweak and QCD effects. The wide range of dilepton invariant masses accessible to this measurement probes different scales of the interaction and provides access to both photon and $Z$ boson dominated regions. The rapidity dependence provides information on the fraction of the initial proton's momentum carried by the interacting partons, which makes the measurement sensitive to the proton parton density functions. The angular distribution allows testing of fundamental properties of the electroweak interactions, giving access to the weak mixing angle via the $A_{FB}$ measurements. The measurements are compared to theoretical predictions calculated at next-to-leading order QCD. The measured cross-sections agree with the theoretical calculation within the uncertainty in the bulk of the measured phase space. The deviation observed in certain phase space regions warrants the study of higher order electroweak and QCD corrections. The measured cross-sections can be used for PDF fits and for the determination of the electroweak parameters.