Search for the top quark in pp̅ collisions at √s = 1.8 TeV

We have searched for evidence of top quarkproduction in pp¯ collisions at 8730;s =1.8 TeV using the D0 detector at the Fermilab Tevatroncollider. For an integrated luminosity of 15 pb -1 , we report results of a search for tt - pairs in the decay modes tt - → eμ +jets,ee+jets,e+jets, and μ +jets. From analyses of these modes we obtain a lower limit on the top quarkmass of 131 GeV/c 2 at the 95% confidence level, assuming standard model branching fractionsand a predicted cross section for tt - production. We discuss the properties of an event for which expected backgrounds are small.