Göttingen 2012 – scientific programme
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T: Fachverband Teilchenphysik
T 39: Top-Quark: Eigenschaften 3
T 39.3: Talk
Wednesday, February 29, 2012, 17:15–17:30, ZHG 105
Non-top-quark related background estimation for the signal process ttγ with the ATLAS detector — •Oliver Rosenthal, Ivor Fleck, and Marcus Rammes — Universität Siegen
Top quark pair events with the radiation of an additional photon (ttγ) are investigated at the ATLAS detector. A first measurement of the ttγ cross section in the single lepton and dilepton decay channel has been performed at √s=7 TeV and an integrated luminosity of 1.04 fb−1. The result is 2.0±0.5(stat.)±0.7(syst.)±0.08(lumi.) pb, which is in agreement with the Standard Model prediction.
The distinction between background and signal photons is a challenging task since photons with similar properties are radiated from the signal process as well as from a large variety of different background processes.
W+jets+γ, Z+jets+γ and QCD+γ are the most significant classes of background consisting of processes with a real photon in the final state. Different methods have been developed and applied to estimate their contributions. These methods will be illustrated in this talk.