# Identification des leptons taus dans l'expérience D0 auprès du Tevatron et recherche de particules supersymétriques se désintégrant avec R_parité violée (couplage $\lambda_{133}$)

Abstract : This thesis concerrns the search of supersymmetric particles in data collected at a center-of-mass energy of 1.96 TeV by the D0 experiment, located at the Tevatron proton-antiproton collider. Although the Standard Model has obtained remarquable success, there are strong armuments to consider it as a low effective theory. Data corresponding to an integrated luminosity of 352 pb$^{-1}$ have been analyzed. The supersymmetry framework considered is the one where R-parity is violated by $\lambda_133}$ coupling. The data seen is consistent with Standard Model and instrumental backgrounds which suggests no evidence for supersymmetry. with $\lambda_133}$ coupling, thus limits on the lower chargino and neutralino masses have been set. To perform this analysis, a method to identify hadronically decaying taus has been developed. This method uses neural networks and exploits the narrowness and low particle multiplicty of tau jets by means of the calorimeter and tracker informations. The efficiency of this method has been measured in data using the Z$\rightarrow \tau \tau \rightarrow \mu \tau _hadr}$ process. This algorithm allows one to reduce the important QCD background by a factor 100 for 50% efficiency.
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Theses

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Submitted on : Tuesday, January 24, 2006 - 10:11:35 AM
Last modification on : Monday, November 9, 2020 - 6:56:03 PM
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• HAL Id : tel-00011450, version 1

### Citation

Anne-Catherine Le Bihan. Identification des leptons taus dans l'expérience D0 auprès du Tevatron et recherche de particules supersymétriques se désintégrant avec R_parité violée (couplage $\lambda_{133}$). Physique des Hautes Energies - Expérience [hep-ex]. Université Louis Pasteur - Strasbourg I, 2005. Français. ⟨tel-00011450⟩

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