We report limits on anomalous ital ZZgamma and ital Zgammagamma couplings derived from an analysis of ital Z+photon production based upon approximately 20pbsup minus1 of the bar p collision data ...recorded by the Collider Detector at Fermilab. We observe good agreement with the standard model expectation that all ital Zgamma couplings are zero. Confidence level intervals for individual couplings and contours for pairs of ital CP-conserving/violating ital ZZgamma and ital Zgammagamma couplings are presented.
We report on a study of ital W+ photon production in approximately 20 pbsup minus1 of ital pminusital bar p collisions at radicalital s=1.8 TeV recorded with the Collider Detector at Fermilab. Our ...results are in good agreement with standard model expectations and are used to obtain limits on anomalous ital CP-conserving ital WWgamma couplings of minus2.3ltDeltakappalt2.2 for lambda=0 and minus0.7ltlambdalt0.7 for Deltakappa=0 at 95% C.L. We obtain the same limits for ital CP-violating couplings. These results provide limits on the higher-order electromagnetic moments of the ital W boson of 0.8ltital gsub ital Wlt3.1 for ital qsup ital esub ital W=1 and minus0.6ltital qsup ital esub ital Wlt2.7 for ital gsub ital W=2 at 95% C.L.
In ital ppital bar pp collisions at radicalital s=1.8TeV we find jet events with a rapidity gap topology. The number of hadrons in the rapidity interval Deltaetasub ital D between leading-jet cones ...was sampled by charged tracks with ital Psub ital Tgt400MeV/ital c. We find excess trackless events beyond that expected in a smooth multiplicity distribution. In a control region outside Deltaetasub ital D we see no excess. For Deltaetasub ital Dgt0.8, the fraction of excess trackless events, consistent with estimates based on exchange of color-singlet digluons, is ital R(gap)=sigmasub jet(gap)/sigmasub jet= 0.0085plus minus0.0012(stat)sub minus0.0012sup +0.0024(syst).
Charge asymmetry has been measured using 19 039 ital W decays recorded by the Collider Detector at Fermilab during the 1992--93 run of the Tevatron Collider. The asymmetry is sensitive to the ratio ...of ital d and ital u quark distributions to ital xlt0.01 at ital Qsup 2approxital Msup 2sub ital W, where nonperturbative effects are minimal. It is found that of the two current sets of parton distributions, those of Martin, Roberts, and Stirling are favored over the sets most recently produced by the CTEQ Collaboration. The ital W asymmetry data provide stronger constraints on ital d/ital u ratio than the recent measurements of ital Fsub 2sup muital n/ital Fsub 2sup muital p, which are limited by uncertainties originating from deuteron corrections.
This Letter describes a direct measurement of the ital W boson decay width, Gamma(ital W), using the high-mass tail of the transverse mass spectrum of ital Wr arrowital enu decays recorded by the ...Collider Detector at Fermilab. We find Gamma(ital W)=2.11plus minus0.28(stat) plus minus 0.16(syst) GeV and compare this direct measurement with indirect means of obtaining the width.
We present the results of a search in ital bar p ital p collisions at radicalital s =1.8 TeV for the top quark decaying to a charged Higgs bosson (ital Hsup plus minus). We search for dilepton final ...states from the decay chain ital t ital bar tr arrowital HH (or ital HW, or ital WW)+ital b ital bar br arrowital ll+ital X. In a sample of 19.3 pbsup minus1 collected during 1992--93 with the Collider Detector at Fermilab, we observe 2 events with a background estimation of 3.0plus minus1.0 events. Limits at 95% C.L. in the (Msub top,Msub ital Hsup plus minus) plane are presented. For the case ital Msub topltital Msub ital W+ital Msub ital b, we exclude at 95% C.L. the entire (ital Msub top,ital Msub Hplus minus) plane for the branching ratio ital B(ital Hr arrowtaunu) larger than 75%. We also interpret the results in terms of the parameter tanbeta of two-Higgs-doublet models.
PDF