Diffractive Dijet Production at sqrt(s)=630 and 1800 GeV at the Fermilab Tevatron

We report a measurement of the diffractive structure function $F_{jj}^D$ of the antiproton obtained from a study of dijet events produced in association with a leading antiproton in $\bar pp$ collisions at $\sqrt s=630$ GeV at the Fermilab Tevatron. The ratio of $F_{jj}^D$ at $\sqrt s=630$ GeV to $F_{jj}^D$ obtained from a similar measurement at $\sqrt s=1800$ GeV is compared with expectations from QCD factorization and with theoretical predictions. We also report a measurement of the $\xi$ ($x$-Pomeron) and $\beta$ ($x$ of parton in Pomeron) dependence of $F_{jj}^D$ at $\sqrt s=1800$ GeV. In the region $0.035<\xi<0.095$, $|t|<1$ GeV$^2$ and $\beta<0.5$, $F_{jj}^D(\beta,\xi)$ is found to be of the form $\beta^{-1.0\pm 0.1} \xi^{-0.9\pm 0.1}$, which obeys $\beta$-$\xi$ factorization.Comment: LaTeX, 9 pages, Submitted to Phys. Rev. Letter

A Study of B0 -> J/psi K(*)0 pi+ pi- Decays with the Collider Detector at Fermilab

We report a study of the decays B0 -> J/psi K(*)0 pi+ pi-, which involve the creation of a u u-bar or d d-bar quark pair in addition to a b-bar -> c-bar(c s-bar) decay. The data sample consists of 110 1/pb of p p-bar collisions at sqrt{s} = 1.8 TeV collected by the CDF detector at the Fermilab Tevatron collider during 1992-1995. We measure the branching ratios to be BR(B0 -> J/psi K*0 pi+ pi-) = (8.0 +- 2.2 +- 1.5) * 10^{-4} and BR(B0 -> J/psi K0 pi+ pi-) = (1.1 +- 0.4 +- 0.2) * 10^{-3}. Contributions to these decays are seen from psi(2S) K(*)0, J/psi K0 rho0, J/psi K*+ pi-, and J/psi K1(1270)

Search for Single-Top-Quark Production in p-pbar Collisions at sqrt(s)=1.8 TeV

We search for standard model single-top-quark production in the W-gluon fusion and W* channels using 106 pb^-1 of data from p-pbar collisions at sqrt(s)=1.8 TeV collected with the Collider Detector at Fermilab. We set an upper limit at 95% C.L. on the combined W-gluon fusion and W* single-top cross section of 14 pb, roughly six times larger than the standard model prediction. Separate 95% C.L. upper limits in the W-gluon fusion and W* channels are also determined and are found to be 13 and 18 pb, respectively.Comment: 6 pages, 2 figures; submitted to Phys. Rev. Let

Measurement of the Ratio of b Quark Production Cross Sections in Antiproton-Proton Collisions at 630 GeV and 1800 GeV

We report a measurement of the ratio of the bottom quark production cross section in antiproton-proton collisions at 630 GeV to 1800 GeV using bottom quarks with transverse momenta greater than 10.75 GeV identified through their semileptonic decays and long lifetimes. The measured ratio sigma(630)/sigma(1800) = 0.171 +/- .024 +/- .012 is in good agreement with next-to-leading order (NLO) quantum chromodynamics (QCD)

First measurement of the ratio B(t -> Wb)/B(t -> Wq) and associated limit on the Cabibbo-Kobayashi-Maskawa element vertical bar V-tb vertical bar RID C-1693-2008 RID A-5169-2010

We present the first measurement of the ratio of branching fractions R equivalent to B(t --> Wb)/B(t --> Wq) from pa collisions at roots = 1.8 TeV. The data set corresponds to 109 pb(-1) of data recorded by the Collider Detector at Fermilab during the 1992-95 Tevatron run. We measure R = 0.94(-0.24)(+0.31)(stat + syst) or R > 0.61 (0.56) at 90% (95)% C.L., in agreement with the standard model predictions. This measurement yields a limit on the Cabibbo-Kobayashi-Maskawa quark mixing matrix element \V-tb\ under the assumption of three generations and unitarity

Branching ratio measurements of exclusive B⁺ decays to charmonium with the Collider Detector at Fermilab

We report on measurements of the branching ratios of the decays B+→chi(c1)(0)(1P)K+ and B+→J/psiK(+)pi(+)pi(-), where chi(c1)(0)(1P)→J/psigamma and J/psi→mu(+)mu(-) in p (p) over bar collisions at roots=1.8 TeV. Using a data sample from an integrated luminosity of 110 pb(-1) collected by the Collider Detector at Fermilab we measure the branching ratios to be BR(B+→chi(c1)(0)(1P)K+)=15.5+/-5.4(stat)+/-1.5(syst)+/- 1.3(br)x10(-4) and BR(B+→J/psiK(+)pi(+)pi(-))=6.9+/- 1.8(stat)+/-1.1(syst)+/-0.4(br)x10(-4) where (br) is due to the finite precision on BR(B+→J/psiK(+)), BR(chi(c1)(0)(1P)→J/psigamma) is used to normalize the signal yield, and (syst) encompasses all other systematic uncertainties

Limits on extra dimensions and new particle production in the exclusive photon and missing energy signature in p(p)over-bar collisions at root s=1.8 TeV

A search for new physics in the exclusive γ∄T channel was performed. Departure from the expected standard model cross section was found. Limits on two specific models of new physics were defined. Furthermore, the limit in a "pseudomodel-independent" manner was detailed

Search for the decay B-s -&gt;mu(+)mu(-)phi in p(p)over-bar collisions at root s=1.8 TeV

We present a search for the flavor-changing neutral current decay B-s-->mu(+)mu(-)phi in p (p) over bar collisions at roots=1.8 TeV, using 91 pb(-1) of data collected at the Collider Detector at Fermilab (CDF). We find two candidate events for this decay, which are consistent with the background estimate of one event, and set an upper limit on the branching fraction of B(B-s-->mu(+)mu(-)phi)<6.7x10(-5) at a 95% confidence level. This is the first limit on the branching fraction of this decay