Search for electroweak production of single top quarks in pp̅ collisions

We present a search for electroweak production of single top quarksin the electron+jets and muon+jets decay channels. The measurements use ≈90pb -1 of data from Run 1 of the Fermilab Tevatroncollider, collected at 1.8 TeV with the DO detector between 1992 and 1995. We use events that include a tagging muon, implying the presence of a b jet, to set an upper limit at the 95% confidence level on the cross section for the s-channel process pp→tb+X of 39 pb. The upper limit for the t-channel process pp→tqb+X is 58 pb.