Dresden 2013 – scientific programme

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T: Fachverband Teilchenphysik

T 38: Top-Quarks: Single-Top 1

T 38.4: Talk

Tuesday, March 5, 2013, 17:30–17:45, HSZ-04

Application of kinematic fitting in Wt associated production analysis at ATLAS — •Irina Cioară, Ian C. Brock, Thomas Loddenkötter, Pienpen Seema, Sebastian Mergelmeyer, and Jan A. Stillings — Physikalisches Institut, Universität Bonn

One of the largest contributions to single top quark production at the LHC comes from the associated production of a top quark and a real W boson (Wt channel). The lepton + jets decay topology of this channel produces one b-jet, one charged lepton, two light-quark jets and one neutrino.
The main sources of background for the Wt signal are top quark pair production and events with a W boson and extra jets. A kinematic fit to the signal topology is performed in order to construct variables that are directly sensitive to how much an event looks like Wt signal. Additionally, a kinematic fit on the tt topology is implemented and its effect on the signal extraction in the 4-jet bin is studied. An artificial neural network is used to separate signal from background using the event kinematics and the information from the kinematic fit.