Top quark search with the D0 1992-1993 data sample

Abstract

We present results on the search for the top quark in pp̅ collisions at √s =1.8 TeV with an integrated luminosity of 13.5±1.6 pb^-1. We have considered tt̅ production in the standard model using electron and muon dilepton decay channels (tt̅→eµ+jets, ee +jets, and µµ+jets) and single-lepton decay channels (tt̅→e+jets and µ+jets) with and without tagging of b quark jets. An analysis of these data optimized for top quark masses below 140 GeV/c² gives a lower top quark mass limit of 128 GeV/c². An analysis optimized for higher top quark masses yields 9 events with an expected background of 3.8± 0.9. If we assume that the excess is due to tt̅ production, and assuming a top quark mass of 180 GeV/c², we obtain a cross section of 8.2± 5.1 pb.