Search for tt-bar-Resonances in the Lepton+Jets Final State

A search for a narrow-width heavy resonance decaying into top quark pairs (X→tt-bar) in pp-bar collisions at √(s) = 1.96 TeV has been performed using data collected with the DOe detector at the Fermilab Tevatron Collider. This analysis considers tt-bar candidate events in the lepton+jets channel using a neural network tagger to identify b-jets and the tt-bar invariant mass distribution to search for evidence of resonant production. The analyzed dataset corresponds to an integrated luminosity of approximately 2.1 fb-1. We find no evidence for a narrow resonance X decaying to tt-bar. Therefore, we set upper limits on σX·B(X→tt-bar) for different hypothesized resonance masses using a Bayesian approach. Within a topcolor-assisted technicolor model, the existence of a leptophobic Z' boson with mass MZ'<760 GeV and width ΓZ' = 0.012MZ' can be excluded at 95% C.L.