Karlsruhe 2011 – scientific programme

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T: Fachverband Teilchenphysik

T 38: Top-Produktion III

T 38.3: Talk

Wednesday, March 30, 2011, 17:15–17:30, 30.22: 130

Identification of single top-quark production in the Wt channel using a kinematic fit at ATLAS — Ian C. Brock, Jan A. Stillings, and •Thomas Loddenkötter — Physikalisches Institut, Universität Bonn

The Wt channel is predicted to give the second largest contribution to the total single top-quark production cross section in proton-proton collisions at the LHC. Furthermore it still is a discovery channel, as at the Tevatron its cross section is almost negligible. The Wt channel is characterised by the associated production of a top-quark and an on-shell W boson. In the lepton plus jets decay channel this leads to one b-quark jet, two light-quark jets, one charged lepton and a neutrino – manifesting itself in missing transverse energy – in the final state.

The study presented tries to reconstruct the decay chain from the measured final state by using a kinematic fitter. The results of the fit are then used to separate the signal from the various brackgrounds, in particular the tt channel, which intereferes with single top Wt production at NLO and is therefore of particular importance for any Wt channel analysis.