Search for narrow tt̅ resonances in pp̅ collisions at √s=1.8 TeV

Abstract

A search for narrow resonances that decay into tt̅ pairs has been performed using 130 pb^-1 of data in the lepton + jets channel collected by the DØ detector in pp̅ collisions at √s=1.8 TeV. There is no significant deviation observed from the standard-model predictions at a top-quark mass of 175 GeV/c². We therefore present upper limits at the 95% confidence level on the product of the production cross section and branching fraction to tt̅ for narrow resonances as a function of the resonance mass M_X. These limits are used to exclude the existence of a leptophobic top-color particle with mass M_X<560 GeV/c², using a theoretical cross section for a width Γ_X=0.012M_X.