Search for a narrow $t\bar t$ resonance in $p\bar p$ collisions at $\sqrt s=1.96\ \text{TeV}$

Abstract

We report a search for a narrow $t\bar t$ resonance that decays into a $\text{lepton+jets}$ final state based on an integrated luminosity of $5.3 \text{ fb}^{−1}$ of proton-antiproton collisions at $\sqrt s=1.96\ \text{TeV}$ collected by the D0 Collaboration at the Fermilab Tevatron Collider. We set upper limits on the production cross section of such a resonance multiplied by its branching fraction to $t\bar t$. We exclude a leptophobic topcolor $Z^′$ at the 95% confidence level for masses below 835 GeV (940 GeV) if its width is 1.2% (3%) of its mass. We also exclude color octet vector bosons (colorons) with masses below 775 GeV.