We present a measurement of the ratio of top-quark branching fractions R = B(t --> Wb)/B(t --> Wq), where q can be a b, s, or a d quark, using lepton-plus-jets and dilepton data sets with an ...integrated luminosity of approximately 162 pb(-1) collected with the Collider Detector at Fermilab during Run II of the Tevatron. The measurement is derived from the relative numbers of tt events with different multiplicity of identified secondary vertices. We set a lower limit of R > 0.61 at 95% confidence level.
We measure the masses of b hadrons in exclusively reconstructed final states containing a J/psi --> mu-mu+ decay using 220 pb(-1) of data collected by the CDF II experiment. We find: m(B+) = 5279.10 ...+/- 0.41(stat.) +/- 0.36(sys.) MeV/c2, m(B0) = 5279.63 +/- 0.53(stat.) +/- 0.33(sys.) MeV/c2, m(B(s)0) = 5366.01 +/- 0.73(stat.) +/- 0.33(sys.) MeV/c2, m(lambda(b)0) = 5619.7 +/- 1.2(stat.) +/- 1.2(sys.) MeV/c2. m(B+) - m(B0) = -0.53 +/- 0.67(stat.) +/- 0.14(sys.) MeV/c2, m(B(s)0) - m(B0) = 86.38 +/- 0.90(stat.) +/- 0.06(sys.) MeV/c2, m(lambda(b)0) - m(B0) = 339.2 +/- 1.4(stat.) +/- 0.1(sys.) MeV/c2. The measurements of the B(s)0, lambda(b)0 mass, m(B(s)0) - m(B0) and m(lambda(b)0) - m(B0) mass difference are of better precision than the current world averages.
We present the results of a search for anomalous resonant production of tau lepton pairs with large invariant mass, the first such search using the CDF II Detector in Run II of the Tevatron pp ...collider. Such anomalous production could arise from various new physics processes. In a data sample corresponding to 195 pb(-1) of integrated luminosity we predict 2.8+/-0.5 events from standard model background processes and observe 4. We use this result to set limits on the production of heavy scalar and vector particles decaying to tau lepton pairs.
We report the first evidence for a fully reconstructed decay mode of the B(c)+- meson in the channel B(c)+- --> J/psi pi+-, with J/psi --> mu+ mu-. The analysis is based on an integrated luminosity ...of 360 pb(-1) in pp collisions at 1.96 TeV center of mass energy collected by the Collider Detector at Fermilab. We observe 14.6 +/- 4.6 signal events with a background of 7.1 +/- 0.9 events, and a fit to the J/psi pi+-mass spectrum yields a B(c)+- mass of 6285.7 +/- 5.3(stat) +/- 1.2(syst) MeV/c2. The probability of a peak of this magnitude occurring by random fluctuation in the search region is estimated as 0.012%.
We present a search for long-lived doubly charged Higgs bosons (H(+/- +/-)), with signatures of high ionization energy loss and muonlike penetration. We use 292 pb(-1) of data collected in pp ...collisions at sqrts = 1.96 TeV by the CDF II detector at the Fermilab Tevatron. Observing no evidence of long-lived doubly charged particle production, we exclude H(+/- +/-)(L) and H(+/- +/-)(R) bosons with masses below 133 GeV/c(2) and 109 GeV/c(2), respectively. In the degenerate case we exclude H(+/- +/-) mass below 146 GeV/c(2). All limits are quoted at the 95% confidence level.
We present the first evidence of charmless decays of the B(0)(s) meson, the decay B(0)(s)--> phiphi, and a measurement of the branching ratio BR(B(0)(s)--> phiphi) using 180 pb(-1) of data collected ...by the CDF II experiment at the Fermilab Tevatron collider. In addition, the BR and direct CP asymmetry for the B+-->phiK+ decay are measured. We obtain BR(B(0)(s)--> phiphi)=14(+6)(-5)(stat)+/-6(syst) x 10(-6), BR(B+-->phiK+)=7.6+/-1.3(stat)+/-0.6(syst) x 10(-6), and A(CP)(B+-->phiK+)= -0.07+/-0.17(stat)+0.03 / -0.02(syst). Both decays are governed in the standard model by second order (penguin) b-->s(-)ss amplitudes.
Phys.Rev.D72:051107,2005 We report on a search for pair production of first-generation scalar
leptoquarks ($LQ$) in $p \bar{p}$ collisions at $\sqrt{s}$=1.96 TeV using an
integrated luminosity of 203 ...$pb^{-1}$ collected at the Fermilab Tevatron
collider by the CDF experiment. We observe no evidence for $LQ$ production in
the topologies arising from $LQ \bar{LQ} \to eqeq$ and $LQ \bar{LQ} \to eq \nu
q$, and derive 95% C.L. upper limits on the $LQ$ production cross section. %as
a function of $\beta$, where $\beta$ is the branching fraction for $LQ \to eq$.
The results are combined with those obtained from a separately reported CDF
search in the topology arising from $LQ\bar{LQ} \to \nu q \nu q$ and 95% C.L.
lower limits on the LQ mass as a function of $\beta = BR(LQ \to eq) $ are
derived. The limits are 236, 205 and 145 GeV/c$^2$ for $\beta$ = 1, $\beta$ =
0.5 and $\beta$ = 0.1, respectively.
We report on a search for pair production of first-generation scalar leptoquarks (\(LQ\)) in \(p \bar{p}\) collisions at \(\sqrt{s}\)=1.96 TeV using an integrated luminosity of 203 \(pb^{-1}\) ...collected at the Fermilab Tevatron collider by the CDF experiment. We observe no evidence for \(LQ\) production in the topologies arising from \(LQ \bar{LQ} \to eqeq\) and \(LQ \bar{LQ} \to eq \nu q\), and derive 95% C.L. upper limits on the \(LQ\) production cross section. %as a function of \(\beta\), where \(\beta\) is the branching fraction for \(LQ \to eq\). The results are combined with those obtained from a separately reported CDF search in the topology arising from \(LQ\bar{LQ} \to \nu q \nu q\) and 95% C.L. lower limits on the LQ mass as a function of \(\beta = BR(LQ \to eq) \) are derived. The limits are 236, 205 and 145 GeV/c\(^2\) for \(\beta\) = 1, \(\beta\) = 0.5 and \(\beta\) = 0.1, respectively.
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