Measurement of WγW\gamma and ZγZ\gamma Production in ppˉp\bar{p} Collisions at s\sqrt{s} = 1.96 TeV

The Standard Model predictions for $W\gamma$ and $Z\gamma$ production are tested using an integrated luminosity of 200 pb$^{-1}$ of \ppbar collision data collected at the Collider Detector at Fermilab. The cross sections are measured selecting leptonic decays of the $W$ and $Z$ bosons, and photons with transverse energy $E_T>7$ GeV that are well separated from leptons. The production cross sections and kinematic distributions for the $W\gamma$ and $Z\gamma$ are compared to SM predictions.Comment: 7 pages, 4 figures, submitted to PR

Observation of Bs-Bsbar Oscillations

We report the observation of Bs-Bsbar oscillations from a time-dependent measurement of the Bs-Bsbar oscillation frequency Delta ms. Using a data sample of 1 fb^-1 of p-pbar collisions at sqrt{s}=1.96 TeV collected with the CDF II detector at the Fermilab Tevatron, we find signals of 5600 fully reconstructed hadronic Bs decays, 3100 partially reconstructed hadronic Bs decays, and 61500 partially reconstructed semileptonic Bs decays. We measure the probability as a function of proper decay time that the Bs decays with the same, or opposite, flavor as the flavor at production, and we find a signal for Bs-Bsbar oscillations. The probability that random fluctuations could produce a comparable signal is 8 X 10^-8, which exceeds 5 sigma significance. We measure Delta ms = 17.77 +- 0.10 (stat) +- 0.07 (syst) ps^-1 and extract |Vtd/Vts| = 0.2060 +- 0.0007 (exp) + 0.0081 - 0.0060 (theor).Comment: 9 pages, 5 figures, submitted to Physical Review Letter

Double Diffraction Dissociation at the Fermilab Tevatron Collider

We present results from a measurement of double diffraction dissociation in $\bar pp$ collisions at the Fermilab Tevatron collider. The production cross section for events with a central pseudorapidity gap of width $\Delta\eta^0>3$ (overlapping $\eta=0$) is found to be $4.43\pm 0.02{(stat)}{\pm 1.18}{(syst) mb}$ [$3.42\pm 0.01{(stat)}{\pm 1.09}{(syst) mb}$] at $\sqrt{s}=1800$ [630] GeV. Our results are compared with previous measurements and with predictions based on Regge theory and factorization.Comment: 10 pages, 4 figures, using RevTeX. Submitted to Physical Review Letter

Measurement of the Ratio of Branching Fractions B(D0 -> K+ pi-)/B(D0 -> K- pi+) using the CDF II Detector

We present a measurement of R_B, the ratio of the branching fraction for the rare decay D0 -> K+ pi- to that for the Cabibbo-favored decay D0 -> K- pi+. Charge conjugate decays are implicitly included. A signal of 2005 +/- 104 events for the decay D0 -> K+ pi- is obtained using the CDF II detector at the Fermilab Tevatron collider. The data set corresponds to an integrated luminosity of 0.35 1/fb produced in p-bar/p collisions at sqrt{s}=1.96 TeV. Assuming no mixing, we find R_B = [ 4.05 +/- 0.21 (stat) +/- 0.11 (syst) ] x 10(-3). This measurement is consistent with the world average, and comparable in accuracy with the best measurements from other experiments.Comment: 7 pages, 3 figure

Measurement of the BB Meson Differential Cross Section, dσ/dpTd\sigma/dp_T, in ppˉp\bar{p} Collisions at s=1.8\sqrt{s} = 1.8 TeV

This paper presents the first direct measurement of the $B$ meson differential cross section, $d\sigma/dp_T$, in $p\bar{p}$ collisions at $\sqrt{s}=1.8$ TeV using a sample of $19.3 \pm 0.7$ pb$^{-1}$ accumulated by the Collider Detector at Fermilab (CDF). The cross section is measured in the central rapidity region $|y| 6.0$ GeV/$c$ by fully reconstructing the $B$ meson decays $B^{+}\to J/\psi K^{+}$ and $B^{0}\to J/\psi K^{*0}(892)$, where $J/\psi \to \mu^+\mu^-$ and $K^{*0} \to K^+ \pi^-$. A comparison is made to the theoretical QCD prediction calculated at next-to-leading order.Comment: 14 pages. Submitted to Phys. Rev. Lett. The postscript file is at http://www-cdf.fnal.gov/physics/pub95/cdf2893_bexcl_xsection.p

Limits on WWZWWZ and WWγWW\gamma couplings from WWWW and WZWZ production in pp‾p\overline{p} collisions at s=1.8\sqrt{s} = 1.8 TeV

Direct limits are set on $WWZ$ and $WW\gamma$ three-boson couplings in a search for $WW$ and $WZ$ production with high transverse momentum in $p\overline{p}$ collisions at $\sqrt{s} = 1.8$ TeV, using the Collider Detector at Fermilab. The results are in agreement with the SU(2) $\times$ U(1) model of electroweak interactions. Assuming Standard Model $WW\gamma$ coupling, the the limits are interpreted as direct evidence for a non-zero $WWZ$ coupling at subprocess energies near 500 GeV. Alternatively, assumiong identical $WWZ$ and $WW\gamma$ couplings, bounds $-0.11 < \kappa < 2.27$ and $-0.81 < \lambda < 0.84$ are obtained at $95\%$ CL for a form factor scale 1000 GeV.Comment: 16 pages, submitted to PRL, URL: http://www-cdf.fnal.gov/physics/pub95/cdf2951_vvprl.p

Search For Charged Higgs Decays of the Top Quark Using Hadronic Decays of the Tau Lepton

This Letter describes a direct search for charged Higgs boson production in proton-antiproton collisions at sqrt(s)=1.8 TeV recorded by the Collider Detector at Fermilab. Two-Higgs-doublet extensions to the standard model predict the existence of charged Higgs bosons. In such models, the branching fraction for top quarks B(t --> H b --> tau nu b) can be large. This search uses the hadronic decays of the tau lepton in this channel to significantly extend previous limits on charged Higgs production.Comment: 6pages, 4 figures, 1 table; LaTeX; submitted to PR

Measurement of the Top Quark Mass with the Collider Detector at Fermilab

This report describes a measurement of the top quark mass in \ppbar collisions at a center of mass energy of 1.8 TeV. The data sample was collected with the CDF detector during the 1992--95 collider run at the Fermilab Tevatron, and corresponds to an integrated luminosity of 106 \pb. Candidate $t\bar{t}$ events in the ``lepton+jets'' decay channel provide our most precise measurement of the top quark mass. For each event a top mass is determined by using energy and momentum constraints on the production of the \ttbar pair and its subsequent decay. A likelihood fit to the distribution of reconstructed masses in the data sample gives a top mass in the lepton+jets channel of 176.1\pm 5.1 (stat.)\pm 5.3 (syst.) \gevcc. Combining this result with measurements from the ``all-hadronic'' and ``dilepton'' decay topologies yields a top mass of 176.1\pm 6.6 \gevcc.Comment: 158 pages, 41 figure

Observation of Bs->K+K- and Measurements of Branching Fractions of Charmless Two-body Decays of B0 and Bs Mesons in p-pbar Collisions at sqrt(s)=1.96 TeV

We search for decays of the type B0(Bs)->h+h'- (where h,h'= K or pi) in 180 pb-1 of p-pbar collisions collected at the Tevatron by the upgraded Collider Detector at Fermilab. We report the first observation of the new mode Bs->K+K- with a yield of 236 +- 32 events, corresponding to (f_s/f_d)*BR(Bs->K+K-)/BR(B0->K+pi-) = 0.46+-0.08(stat.)+-0.07(syst.), where f_s/f_d is the ratio of production fractions of Bs and B0. We find results in agreement with world averages for the B0 modes, and set the following new limits at 90% CL: BR(Bs->K-pi+) pi+pi-) < 1.7*10^{-6}.Comment: 7 Pages, 2 Figures. v3: added minor corrections made in proof before publicatio

Measurement of the D+->pi(+) pi(0) and D+-> K+ pi(0) branching fractions

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