# Etude de la production de paires de squarks bottom se désintégrant dans le canal $\tilde b \rightarrow b+ \tilde \chi^0_1$ auprès du détecteur D0 au Run II du Tevatron

Abstract : The DØ detector is located at the proton-antiproton collider, the Tevatron, at Fermilab (Chicago). The new data-taking period, refered as "Run II", started in april 2001. The available Energy in the center of mass is s^1/2 ~1.96 TeV, and the expected luminosity is 8.6 10^31 cm-2s-1.
The bottom squark pairs production study in the decay channel $\tilde b \rightarrow b+ \tilde \chi^0_1$ has been performed on the first Run II data available for physics studies, with a data sample corresponding to 4.1 +- 0.4 pb-1. This study takes place in the theoretical framework of supersymetric models with R-parity conservation, and whith a light $\tilde b$ decaying dominantly in the $\tilde b \rightarrow b+ \tilde \chi^0_1$ channel (BF ~100%). As no b-tagging techniques were available at this time, the final state "jets and missing transverse energy E_T barré)" was considered.
This preliminary study lead to two important results. First, the E_T barré distribution after all analysis cuts does not show anomalous tails, which means that instrumental effects are well understood. This is an important step as many processes produce a significant amount of E_T barré in the Standard Model and its extensions, i.e. Supersymetry.
No excess of events was observed in the date, compared to the Standard Model (SM) predictions. Limits at 95% C.L. were set on the production of events beyond the SM, in the "jets and E_T barré" final state.
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Submitted on : Friday, July 25, 2003 - 2:50:13 PM
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• HAL Id : tel-00003173, version 1

### Citation

Frédéric Villeneuve-Séguier. Etude de la production de paires de squarks bottom se désintégrant dans le canal $\tilde b \rightarrow b+ \tilde \chi^0_1$ auprès du détecteur D0 au Run II du Tevatron. Physique des Hautes Energies - Expérience [hep-ex]. Université de la Méditerranée - Aix-Marseille II, 2003. Français. ⟨tel-00003173⟩

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