Prospects for Measuring Top Pair Production in the di-lepton Channel with early ATLAS Data at √s = 10TeV

This page contains approved plots and results as they appear in the ATL-PHYS-PUB-2009-086 note. Only the note contains all the relevant information and should thus be consulted if one of the plots is used.

Figure 1: Electron trigger efficiency as a function of pT (on the left) and η (on the right) for the signal events. The shaded area shows the pT and η distributions of reconstructed electrons that match true electrons from W decays. The efficiencies are measured with respect to the offline event selection (Section 2.2).

Figure 2: Electron reconstruction efficiencies as a function of electron pT (left) and η (right) for signal events as predicted from the simulation. The shaded area shows the pT and η distributions of true electrons from W decays.

Figure 3: Muon reconstruction efficiencies as a function of muon pT (left) and η (right) for signal events as predicted from the simulation. The shaded area shows the pT and η distributions of true muons from W decays.

Figure 5: Tight fake probabilities f measured as a function of pT for muons (left) and electrons (right) in a multijet sample.

Figure 6: Fake predictions for ee (top left), eμ (top right), and μμ (bottom) as a function of the number of jets.

Figure 7: Minimum angular distance in
R between reconstructed leptons and leptons from the truth record which originate from t → W → l decays. Overflow is shown at log(
R) = 1.

Figure 8: Missing transverse energy distribution (left) after requiring two opposite signed leptons and jet multiplicity distribution (right) after all cuts (except the Njets > 1 cut) for ee dilepton signal and MC based background estimations after all cuts. The samples are normalized to 200 pb−1.

Figure 9: Missing transverse energy distribution (left) after requiring two opposite signed leptons and jet multiplicity distribution (right) after all cuts (except the Njets > 1 cut) for μμ dilepton signal and MC based background estimations after all cuts. The samples are normalized to 200 pb−1.

Figure 10: Missing transverse energy distribution (left) after requiring two opposite signed leptons and jet multiplicity distribution (right) after all cuts (except the Njets > 1 cut) for eμ dilepton signal and MC based background estimations after all cuts. The samples are normalized to 200 pb−1.

Figure 11: The log-likelihood curves for ee, μμ and eμ channels. The solid blue curve is the log of the profile likelihood ratio −log λ(σsig), which includes all sources of systematics. The dotted red curve is the log of the likelihood ratio −log r(σsig), which can be considered as including only statistical uncertainties. The horizontal green lines indicate 68%, 90%, and 95% thresholds (from bottom to top).