We have searched for heavy neutral gauge bosons (ital Zsup prime) in ital bar pp collisions at radicalital s=1.8 TeV. The data were obtained using the CDF detector during the 1992--1993 run ...corresponding to an integrated luminosity of 19.7plus minus0.7 pbsup minus1. We present a 95% confidence level upper limit on the production cross section times the branching ratio of ital Zsup prime decaying into dielectrons as a function of ital Zsup prime mass. Assuming standard model coupling strengths, we exclude a ital Zsup prime with a mass less than 505 GeV/ital csup 2. We also present lower mass limits for ital Zsup prime bosons from Esub 6 models and the alternative left-right model.
We present the results of a search for the top quark in 19.3 pbsup minus1 of ital bar pp collisions at radicalital s =1.8 TeV. The data were collected at the Fermilab Tevatron collider using the ...Collider Detector at Fermilab (CDF). The search includes standard model ital tbar t decays to final states ital eenubar nu, ital emunubar nu, and mumunubar nu as well as ital e+nu+jets or mu+nu+jets. In the (ital e,mu)+nu+jets channel we search for ital b quarks from ital t decays via secondary vertex identification and via semileptonic decays of the ital b and cascade ital c quarks. In the dilepton final states we find two events with a background of 0.56sub minus0.13sup +0.25 events. In the ital e,mu+nu+jets channel with a ital b identified via a secondary vertex, we find six events with a background of 2.3plus minus0.3. With a ital b identified via a semileptonic decay, we find seven events with a background of 3.1plus minus0.3. The secondary vertex and semileptonic-decay samples have three events in common. The probability that the observed yield is consistent with the background is estimated to be 0.26%. The statistics are too limited to firmly establish the existence of the top quark; however, a natural interpretation of the excess is that it is due to ital tbar t production. We present several cross-checks. Some support this hypothesis; others do not. Under the assumption that the excess yield over background is due to ital tbar t, constrained fitting on a subset of the events yields a mass of 174plus minus10sub minus12sup +13 GeV/ital csup 2 for the top quark. The ital tbar t cross section, using this top quark mass to compute the acceptance, is measured to be 13.9sub minus4.8sup +6.1 pb.
