arXiv subjects

CDF Collaboration

Publications and source records attributed to CDF Collaboration.

353 records · Page 20Linked to original sources

arXiv1998

Observation of B^+ -> psi(2S) K^+ and B^0 -> psi(2S) K^*(892)^0 Decays and Measurements of B-Meson Branching Fractions into J/psi and psi(2S) Final States

We report the observations of the decays B^+ -> psi(2S) K^+ and B^0 -> psi(2S) K^*(892)^0 in ppbar collisions at a center-of-mass energy of 1.8 TeV using a 110 pb^{-1} data sample recorded by the Collider Detector at Fermilab. We also reconstruct the decays B^+ -> J/psi K^+ and B^0 -> J/psi K^*(892)^0 and measure the six ratios of branching fractions of these four decays. The relative branching-fraction results are shown to be consistent with phenomenological factorization calculations of hadronic B-meson decays. We use the world-average branching fraction Br(B^+ -> J/psi K^+) to derive Br(B^+ -> psi(2S) K^+) = (0.56 +/- 0.08 +/- 0.10) x 10^{-3}, Br(B^0 -> psi(2S) K^*(892)^0) = (0.92 +/- 0.20 +/- 0.16) x 10^{-3}, and Br(B^0 -> J/psi K^*(892)^0) = (1.78 +/- 0.14 +/- 0.29) x 10^{-3}, where the first and second uncertainties are statistical and systematic, respectively.

hep-ex↗

arXiv1998

Searches for New Physics in Diphoton Events in proton anti-proton collisions at sqrt(s)=1.8TeV

We present a detailed description of a search for anomalous production of missing E_T ($\mett$), jets, leptons ($e, μ, τ$), b-quarks, or additional photons in events containing two isolated, central ($|η|<1.0$) photons with $\Et > 12$ GeV}. The results are consistent with standard model expectations, with the possible exception of one event that has in addition to the two photons a central electron, a high-E_T electromagnetic cluster, and large $\mett$. We set limits using two specific SUSY scenarios for production of diphoton events with $\mett$.

hep-ex↗

arXiv1998

Measurement of the CP-Violation Parameter $\sin(2β)$ in $B^0_d/\bar{B}{^0_d} \to J/ψK^0_S$ Decays

We present a measurement of the time-dependent asymmetry in the rate for $\bar{B}{^0_d}$ versus $B^0_d$ decays to $J/ψK^0_S$. In the context of the Standard Model this is interpreted as a measurement of the CP-violation parameter $\sin(2β)$. A total of $198\pm 17$ $B^0_d/\bar{B}{^0_d}$ decays were observed in $p\bar{p}$ collisions at $\sqrt{s} = 1.8$ TeV by the CDF detector at the Fermilab Tevatron. The initial $b$-flavor is determined by a same side flavor tagging technique. Our analysis results in $\sin(2β) = 1.8\pm 1.1(stat)\pm 0.3(syst)$.

hep-ex↗

arXiv1998

Observation of the B_c Meson in p-bar p Collisions at sqrt{s} = 1.8 TeV

We have observed bottom-charm mesons B_c via the decay mode Bc -> J/psi lepton neutrino in 1.8 TeV p-bar p collisions using the CDF detector at the Fermilab Tevatron. A fit of background and signal contributions to the J/psi + lepton mass distribution yielded 20.4 +6.2 -5.5 events from B_c mesons. A fit to the same distribution with background alone was rejected at the level of 4.8 standard deviations. We measured the B_c mass to be 6.40 +- 0.39 +- 0.13 GeVc^2 and the B_c lifetime to be tau(B_c) = 0.46 +0.18 -0.16 +- 0.03 ps. We measured the production cross section times branching ratio for B_c -> J/psi lepton neutrino relative to that for B+ -> J/psi K to be 0.132 +0.041 -0.037 (stat) +- 0.031 (syst) +0.032 -0.020 (lifetime).

hep-ex↗

arXiv1998

Observation of B_c Mesons in p-bar p Collisions at sqrt{s} = 1.8 TeV

We report the observation of bottom-charmed mesons B_c in 1.8 TeV p-bar p collisions using the CDF detector at the Fermilab Tevatron. The B_c mesons were found through their semileptonic decays, B_c -> J/psi lepton X. A fit to the J/psi lepton mass distribution yielded 20.4 +6.2 -5.5 events from B_c mesons. A test of the null hypothesis, i.e. an attempt to fit the data with background alone, was rejected at the level of 4.8 standard deviations. By studying the quality of the fit as a function of the assumed B_c mass, we determined M(B_c) = 6.40 +- 0.39 +- 0.13 GeV/c^2. From the distribution of trilepton intersection points in the plane transverse to the beam direction we measured the B_c lifetime to be tau(B_c) = 0.46 +0.18 -0.16 +- 0.03 ps. We also measured the ratio of production cross section times branching fraction for B_c -> J/psi lepton neutrino relative to that for B+ -> J/psi K to be: 0.132 +0.041 -0.037 (stat) +- 0.031 (syst) +0.032 -0.020 (lifetime)

hep-ex↗

arXiv1998

Search for Chargino-Neutralino Associated Production at the Fermilab Tevatron Collider

We have searched in $p \bar{p}$ collisions at $\sqrt{s}$ = 1.8 TeV for events with three charged leptons and missing transverse energy. In the Minimal Supersymmetric Standard Model, we expect trilepton events from chargino-neutralino ($\chione \chitwo$) pair production, with subsequent decay into leptons. We observe no candidate $e^+e^-e^\pm$, $e^+e^-μ^\pm$, $e^\pmμ^+μ^-$ or $μ^+μ^-μ^\pm$ events in 106 pb$^{-1}$ integrated luminosity. We present limits on the sum of the branching ratios times cross section for the four channels: $σ_{\chione\chitwo}\cdot $BR$(\chione\chitwo\to 3\ell+X) < 0.34$~pb, M$_\chione > $ 81.5 \mgev\sp and M$_\chitwo > $ 82.2 \mgev\sp for $\tanβ=2$, $μ=-600$~\mgev\sp and M$_\squark=$ M$_\gluino$.

hep-ex↗

arXiv1998

Searches for New Physics in Diphoton Events in proton anti-proton collisions at sqrt(s)=1.8TeV

We have searched for anomalous production of missing E$_{\rm T}$ ($\mett$), jets, leptons ($e, μ, τ$), $b$-quarks, or additional photons in events containing two isolated, central \mbox{($|η|<1.0$)} photons with \mbox{$\Et>12$~GeV}. The results are consistent with standard model expectations, with the possible exception of one event that has in addition to the two photons a central electron, a high-E$_{\rm T}$ electromagnetic cluster, and large $\mett$. We set limits using two specific SUSY scenarios for production of diphoton events with $\mett$.

hep-ex↗

arXiv1997

Measurement of the B0 B0-bar oscillation frequency using pi-B meson charge-flavor correlations in p p-bar collisions at sqrt{s} = 1.8 TeV

We present a measurement of the B0 B0-bar oscillation frequency using a flavor tagging method based on correlations of B meson flavor with the charge of other particles produced in p p-bar collisions at sqrt{s} = 1.8 TeV. Such correlations are expected to arise from b quark hadronization and from B** decays. We partially reconstruct B mesons using the semileptonic decays B0 -> lepton D(*)- X. and B+ -> lepton D0-bar X$. From the oscillation frequency, we obtain the mass difference between the two B0 mass eigenstates, Delta m_d = 0.471 {+0.078} {-0.068}(stat) +- 0.034 (syst) hbar ps-1, and measure the efficiency and purity of this flavor tagging method for both charged and neutral B mesons.

hep-ex↗

arXiv1997

Properties of Jets in W Boson Events from 1.8 TeV pbar p Collisions

We present a study of events with W bosons and hadronic jets produced in pbar p collisions at a center of mass energy of 1.8 TeV. The data consist of 51400 W^+/- -> e^+/- nu decay candidates from 108 pb^-1 of integrated luminosity collected with the CDF detector at the Tevatron Collider. The cross sections and jet production properties have been measured for W + \geq 1 to \geq 4 jet events. The data are compared to predictions of leading order QCD matrix element calculations with added gluon radiation and simulated fragmentation.

hep-ex↗

arXiv1997

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.

hep-ex↗

arXiv1997

Observation of Diffractive W Boson Production at the Tevatron

We report the first observation of diffractively produced W bosons. In a sample of W -> e nu events produced in p-barp collisions at sqrt{s}=1.8 TeV, we find an excess of events with a forward rapidity gap, which is attributed to diffraction. The probability that this excess is consistent with non-diffractive production is 1.1 10^{-4} (3.8 sigma). The relatively low fraction of W+Jet events observed within this excess implies that mainly quarks from the pomeron, which mediates diffraction, participate in W production. The diffractive to non-diffractive W production ratio is found to be R_W=(1.15 +/- 0.55)%.

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