# Production électrofaible du quark top au Run II de l'éxpérience D0

Abstract : This thesis deals with the search for electroweak production of the top quark (single top in $s$ and $t$
channels) in ppbar collisions at the Tevatron in the D0 eperiment with an integrated luminosity of
370~pb$^{-1}$. This process has not been obbserved yet.
Identifying the bottom qurk jet from the top decay plays a major role in this analysis. Impact parameters
of tracks attached to a jet are converted into the probability for the jet to originate from the primary
vertex. This algorithm has a 45% tagging efficiency for a 0.5% mistag rate.
The searched signature consists in 2 to 4 jets with at least one bottom quark jet, one charged lepton
and missing energy. A multivariate analysis is needed to separate the signal from the main
backgrounds. The achieved sensitivity is not sufficient enough to reach observation and we computed
upper limits at the 95% confidence level of 5~pb ($s$-channel) and 4.3~pb ($t$-channel) on single top
production cross-sections.
Keywords :
Document type :
Theses

https://tel.archives-ouvertes.fr/tel-00069608
Contributor : Yvette Heyd <>
Submitted on : Thursday, May 18, 2006 - 4:14:06 PM
Last modification on : Thursday, April 23, 2020 - 2:26:21 PM
Long-term archiving on: : Saturday, April 3, 2010 - 9:24:46 PM

### Identifiers

• HAL Id : tel-00069608, version 1

### Citation

Benoît Clément. Production électrofaible du quark top au Run II de l'éxpérience D0. Physique des Hautes Energies - Expérience [hep-ex]. Université Louis Pasteur - Strasbourg I, 2006. Français. ⟨tel-00069608⟩

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