Search for Narrow Width tbar t Resonances in pbar p Collisions at √ {s} =1.8\ Tev

We present a preliminary result on a search for narrow width resonances that decay into tbar t pairs using 130 pb^-1 of lepton plus jets data in pbar p collisions at √ {s} =1.8\ TeV. No significant deviation from Standard Model prediction is observed. 95% C.L. upper limits on the production cross section of the narrow width resonance times its branching fraction to tbar t are presented for different resonance masses M_X. We also exclude the existence of a leptophobic topcolor particle, X, with M_X < 560 GeV/c² for a width Γ_X = 0.012M_X.