Recherche du partenaire supersymétrique du quark Top dans sa désintégration en 3 corps au sein de l'expérience D0 auprès du TeVatron et calibration du calorimètre électromagnétique de D0.

摘要

Supersymmetry is one of the most natural extensions of the Standart Model. At low energy it may consist in the Minimal Supersymmetric Standart Model which is the framwork chosen to perform the search of the stop with 350pb-1 of data collected by DØ during the RunIIa period of the TeVatron. We selected the events with an electron, a muon, missing transverse energy and non isolated tracks, signature for the stop decay in 3-body. Since no significatif excess of signal is seen, the results are interpreted in terms of limit on thestop production cross-sections, in such a way that we extend the existing exclusion region in the parameter space (Mstop-Msneutrino) up to stop masses of 168 (140) GeV for sneutrino masses of 50 (94) GeV. Finally, because of the crucial role of the electromagnetic calorimeter, a fine calibration was performed using Z-->ee events, which improved significatively the energiy resolution.