Search for resonant ttbar production in ppbar collisions at sqrt{s}=1.96 TeV

Abstract

We report on a search for narrow-width particles decaying to a top and antitop quark pair. The data set used in the analysis corresponds to an integrated luminosity of 680 pb^{-1} collected with the Collider Detector at Fermilab in Run II. We present 95% confidence level upper limits on the cross section times branching ratio. Assuming a specific topcolor-assisted technicolor production model, the leptophobic Z' with width Γ_{Z'}=0.012M_{Z'}, we exclude the mass range M_{Z'} < 725 GeV/c^2 at the 95% confidence level.

Figures (3)

• Figure 1: Reconstructed $M_{t\bar{t}}$ distributions for two simulated standard model backgrounds. We plot the samples with the "hardest" ($t\bar{t}$) and the "softest" (diboson) spectrum (normalized to unity); all the others lie in between. The inset shows the reconstructed $M_{t\bar{t}}$ distributions for five signal samples.
• Figure 2: The reconstructed $M_{t\bar{t}}$ spectrum (data) and the standard model prediction in the search region above 400 ${\rm{GeV}}/c^2$. The inset shows the same distributions in logarithmic scale.
• Figure 3: Predicted and experimental 95% CL upper limits using data corresponding to $680 ~\rm{pb^{-1}}$ of integrated luminosity, together with the leptophobic topcolor $Z'$ cross section prediction. Dark and light areas define the $1 \sigma$ and $2 \sigma$ ranges for the expected limits. The arrow marks the mass upper limit.