Reconstruction of High Mass t¯t Resonances in the Lepton+Jets Channel

This page contains approved plots and results as they appear in the ATL-PHYS-PUB-2009-081 note. Only the note contains all the relevant information and should thus be consulted if one of the plots is used.

Figure 2 : Fake rejection for muonic tops in l+jets Z0 ! t¯t: a) 2-d distributions of xμ, yμ for real muonic tops: selected events are required to lie above the line; b) 2-d distributions of xμ, yμ for fake muonic tops: selected events are required to lie above the line; c) Selection efficiency for real muonic tops (circles) and fraction of fake muonic tops w.r.t. all preselected events in the signal sample before (squares), and after (triangles) the cut.

Figure 3: Muonic top candidates in QCD multijet samples: a) 2-d distributions of xμ, yμ. Selected events are required to lie above the line; b) Selection efficiency of the 2-d cut after preselection.

Figure 4: Electronic top quark decays: a) y0e distribution for signal. (The dashed line indicates the cut.) b) y0e distribution for QCD multijet background. c) 2-d distributions of xe, ye for electronic tops after the cut on y0e: selected events are required to lie above the line. d) 2-d distributions of xe, ye for electronic top candidates from QCD multijet samples after the cut on y0e: selected events are required to lie above the line. e) Selection efficiencies of the proposed cuts for signal, and f) Selection efficiencies of the proposed cuts for QCD background after preselection.

Figure 5: Normalized pdfs: a) 1st k? splitting scale for signal (plain line) and background (dashed line); b) 2nd k? splitting scale for signal (plain line) and background (dashed line); c) 3rd k? splitting scale for signal (plain line) and background (dashed line); d) Jet mass for signal (plain line) and background (dashed line).

Figure 6: Likelihood distributions and selection efficiency (as a function of jet pT ) for hadronic top monojets: a) Jet pT versus likelihood variable yL for signal; b) Jet pT versus likelihood variable yL for background; c) Selection efficiencies for a likelihood cut (yL > 0.6).

Figure 7: Z0 boson mass reconstruction with (solid) and without (dashed) the addition of energy contributions in rings around the selected top candidates for mZ0 = 2 (a) and 3 (b) TeV.

Figure 8: Comparison of energy deposits for the Z0 boson sample (m = 3 TeV). Short-dashed line is the energy in a ring around the hadronic top monojet, the long-dashed line in a ring around the leptonic top and the solid line, in a cone away from the two tops. For the solid line, entries at zero have been suppressed (see text).

Figure 9: Distribution of the generated mass minus the reconstructed mass for the m = 2 (a) and 3 (b) TeV Z0 boson.

Figure 10: Total selection efficiency (m = 2 TeV Z0 boson) as a function of leading jet pT requiring yL > 0.6. In this plot, circles and plain error lines are efficiencies w.r.t. events where all required objects are reconstructed, triangles and dashed error lines are efficiencies w.r.t. all events in the sample.

Figure 11: Total selection efficiency (m = 3 TeV Z0 boson) as a function of leading jet pT requiring yL > 0.6. In this plot, circles and plain error lines are efficiencies w.r.t. events where all required objects are reconstructed, triangles and dashed error lines are efficiencies w.r.t. all events in the sample.

Figure 12: Total selection efficiency for QCD multijet background (a) and resulting differential crosssection (b) as a function of leading jet pT requiring yL > 0.6.