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CDF Collaboration

Publications and source records attributed to CDF Collaboration.

At least 235 records · Page 13Linked to original sources
arXiv2007

First Measurement of the Ratio of Central-Electron to Forward-Electron W Partial Cross Sections in p-pbar Collisions at sqrt{s} = 1.96 TeV

We present a measurement of sigma(p-pbar -> W) x B(W->enu) at sqrt{s}=1.96 TeV, using electrons identified in the forward region (1.2 <|eta|<2.8) of the CDF II detector in 223 pb-1 of data. We measure sigma x B = 2796 +-13(stat)+95-90(syst)+-162(lum)pb. Combining this result with a previous CDF measurement obtained using electrons in the central region (|eta|<1), we present the first measurement of the ratio of central-electron to forward-electron W partial cross sections R_exp=0.925+-0.006(stat)+-0.032(syst), consistent with theoretical predictions using Coordinated Theoretical-Experimental Preoject on QCD (CTEQ) and Martin-Roberts-Stirling-Thorne (MRST) parton distribution functions.

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arXiv2007

Limits on the Production of Narrow t-tbar Resonances in p-pbar Collisions at sqrt(s)=1.96 TeV

We search for evidence of resonant top quark pair production in 955 pb-1 of p-pbar collisions at sqrt(s)=1.96 TeV recorded with the CDF II detector at the Fermilab Tevatron. For fully reconstructed candidate t-tbar events triggered on leptons with large transverse momentum and containing at least one identified b-quark jet, we compare the invariant mass spectrum of t-tbar pairs to the expected superposition of standard model t-tbar, non-t-tbar backgrounds, and a simple resonance model based on a sequential Z' boson. We establish upper limits for sigma(p-pbar to Z') times Br(Z' to t-tbar) in the Z' mass interval from 450 GeV/c2 to 900 GeV/c2. A topcolor leptophobic Z' is ruled out below 720 GeV/c2, and the cross section of any narrow Z'-like state decaying to t-tbar is found to be less than 0.64 pb at 95% C.L. for M(Z') above 700 GeV/c2.

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arXiv2007

Search for Standard Model Higgs Bosons Produced in Association with W Bosons

We report on the results of a search for standard model Higgs bosons produced in association with W bosons from p-pbar collisions at root s = 1.96 TeV. The search uses a data sample corresponding to approximately 1 fb-1 of integrated luminosity. Events consistent with the W to l-nu and H to b-bbar signature are selected by triggering on a high-pT electron or muon candidate and tagging one or two of the jet candidates as having originated from b quarks. A neural network filter rejects a fraction of tagged charm and light flavor jets, increasing the b-jet purity in the sample and thereby reducing the background to Higgs boson production. We observe no excess l-nu-b-bbar production beyond the background expectation, and we set 95% confidence level upper limits on the production cross section times branching fraction sigma(p-pbar to WH) times Br(H to b-bbar) ranging from 3.9 to 1.3 pb, for specific Higgs boson mass hypotheses in the range 110 to 150 GeV/c2, respectively.

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arXiv2007

Cross Section Constrained Top Quark Mass Measurement from Dilepton Events at the Tevatron

We report the first top quark mass measurement that uses a cross section constraint to improve the mass determination. This measurement is made with a dilepton $t\bar{t}$ event sample collected with the CDF II detector. From a data sample corresponding to an integrated luminosity of 1.2 fb$^{-1}$, we measure a top quark mass of $\rm{170.7^{+4.2}_{-3.9}(stat)\pm2.6(syst)}$ $\rm{\pm2.4(theory) GeV/{\it{c}}^{2}}$. The measurement without the cross section constraint results in a top quark mass of $\rm{169.7^{+5.2}_{-4.9}(stat)\pm3.1(syst) GeV/{\it{c}}^{2}}$.

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arXiv2007

Search for single top production using multivariate analyses at CDF

This article reports on recent searches for single-top-quark production by the CDF collaboration at the Tevatron using a data set that corresponds to an integrated luminosity of 955 fb^-1. Three different analyses techniques are employed, one using likelihood discriminants, one neural networks and one matrix elements. The sensitivity to single-top production at the rate predicted by the standard model ranges from 2.1 to 2.6 sigma. While the first two analyses observe a deficit of single-top like events compared to the expectation, the matrix element method observes an excess corresponding to a background fluctuation of 2.3 sigma. The null results of the likelihood and neural network analyses translate in upper limits on the cross section of 2.6 pb for the t-channel production mode and 3.7 pb for the s-channel mode at the 95% C.L. The matrix element result corresponds to a measurement of 2.7^{+1.5}_{-1.3} pb for the combined t- and s-channel single-top cross section. In addition, CDF has searched for non-standard model production of single-top-quarks via the s-channel exchange of a heavy W' boson. No signal of this process is found resulting in lower mass limits of 760 GeV/c^2 in case the mass of the right-handed neutrino is smaller than the mass of the right-handed W' or 790 GeV/c^2 in the opposite case.

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arXiv2007

Associated Production for the Standard Model Higgs at CDF

We report the latest result for the search for the standard model higgs produced in association with a W and a Z boson at CDF. The results include about 1 to 1.7 fb-1 of data collected by CDF in run II of the Tevatron. Novel analysis techniques have been developed to enhance the sensitivity of these searches.

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arXiv2007

Search for Exclusive Gamma Gamma Production in Hadron-Hadron Collisions

We have searched for exclusive 2-photon production in proton-antiproton collisions at sqrt{s} = 1.96 TeV, using 532/pb of integrated luminosity taken by the Run II Collider Detector at Fermilab. The event signature requires two electromagnetic showers, each with transverse energy E_T > 5 GeV and pseudorapidity |eta|<1.0, with no other particles detected in the event. Three candidate events are observed. We discuss the consistency of the three events with gamma-gamma, pi0-pi0, or eta-eta production. The probability that other processes fluctuate to 3 events or more is 1.7x10^-4. An upper limit on the cross section of p+pbar --> p+gamma-gamma+pbar is set at 410 fb with 95% confidence level.

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arXiv2007

Sleuth at CDF, a quasi-model-independent search for new electroweak scale physics

These proceedings describe Sleuth, a quasi-model-independent search strategy targeting new electroweak scale physics, and its application to 927 pb^-1 of CDF II data. Exclusive final states are analyzed for an excess of data beyond the Standard Model prediction at large summed scalar transverse momentum. This analysis of high-pT data represents one of the most encompassing searches so far conducted for new physics at the energy frontier.

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arXiv2007

Search for rare b-meson decays at CDF

We report on the search for $B^0_s\toμ^+μ^-$, $B^0_d\toμ^+μ^-$ decays and $b\to s μ^+μ^-$ transitions in exclusive decays of B mesons using the CDF II detector at the Fermilab Tevatron Collider. Using 2 fb$^{-1}$ of Run II data we find upper limits on the branching fractions $\mathcal{B}(B^0_s\toμ^+μ^-)<5.8\times 10^{-8}$ and $\mathcal{B}(B^0_d\toμ^+μ^-)<1.8\times 10^{-8}$ at 95% confidence level. The results for the branching fractions of the $b\to s μ^+μ^-$ transitions using 924 pb$^{-1}$ of Run II data are $\mathcal{B}(B^+\toμ^+μ^-K^+)=(0.60\pm0.15\pm0.04)\times 10^{-6}$, $\mathcal{B}(B^0_d\toμ^+μ^-K^{*0})=(0.82\pm0.31\pm0.10)\times 10^{-6}$ and $\mathcal{B}(B^0_s\to μ^+μ^-ϕ)/\mathcal{B}(B^0_s\to J/ψϕ) < 2.61\times 10^{-3}$ at 95% confidence level.

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arXiv2007

Branching Fractions and Direct CP Asymmetries of Charmless B Decay Modes at CDF

We present new CDF results on the branching fractions and time-integrated direct CP asymmetries for $B^0$ and $B^0_s$ decay modes into pairs of charmless charged hadrons (pions or kaons). The data-set for this update amounts to 1 $\mathrm{fb}^{-1}$ of $p\bar p$ collisions at a center of mass energy 1.96 $\mathrm{TeV}$. We report the first observation of the $B_s \to K^- π^+$ mode and a measurement of its branching fraction and direct CP asymmetry. We also observe for the first time two charmless decays of the $Λ_b^0$-baryon: $Λ_b^0 \to pπ^-$ and $Λ_b^0 \to pK^-$.

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arXiv2007

Latest results on b-hadron spectroscopy from CDF

B-hadron spectroscopy presents an interesting window for the study of QCD. CDF has performed a number of studies involving the production and spectroscopy of B mesons. Among these studies are the first direct observation of the Bc, and the first observation of both narrow states of the Bs**. In addition, measurements are made of the B** masses and widths and the best limit on the production of Eta_b is set.

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arXiv2007

Searches for Direct Pair Production of Supersymmetric Top and Supersymmetric Bottom Quarks in p-pbar Collisions at sqrt(s)=1.96 TeV

We search for direct pair production of supersymmetric top quarks and supersymmetric bottom quarks in proton-antiproton collisions at sqrt(s)=1.96 TeV, using 295 pb^-1 of data recorded by the Collider Detector at Fermilab (CDF II) experiment. The supersymmetric top (supersymmetric bottom) quarks are selected by reconstructing their decay into a charm (bottom) quark and a neutralino, which is assumed to be the lightest supersymmetric particle. The signature of such processes is two energetic heavy-flavor jets and missing transverse energy. The number of events that pass our selection for each search process is consistent with the expected standard model background. By comparing our results to the theoretical production cross sections of the supersymmetric top and supersymmetric bottom quarks in the minimal supersymmetric standard model, we exclude, at a 95% confidence level in the frame of that model, a supersymmetric top quark mass up to 132 GeV/c^2 for a neutralino mass of 48 GeV/c^2, and a supersymmetric bottom quark mass up to 193 GeV/c^2 for a neutralino mass of 40 GeV/c^2.

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arXiv2007

Search for resonant ttbar production in ppbar collisions at sqrt{s}=1.96 TeV

We report on a search for narrow-width particles decaying to a top and antitop quark pair. The data set used in the analysis corresponds to an integrated luminosity of 680 pb^{-1} collected with the Collider Detector at Fermilab in Run II. We present 95% confidence level upper limits on the cross section times branching ratio. Assuming a specific topcolor-assisted technicolor production model, the leptophobic Z' with width Γ_{Z'}=0.012M_{Z'}, we exclude the mass range M_{Z'} < 725 GeV/c^2 at the 95% confidence level.

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arXiv2007

Measurement of the p anti-p to t anti-t Production Cross Section and the Top Quark Mass at sqrt{s}=1.96 TeV in the All-Hadronic Decay Mode

We report the measurements of the t anti-t production cross section and of the top quark mass using 1.02 fb^-1 of p anti-p data collected with the CDFII detector at the Fermilab Tevatron. We select events with six or more jets on which a number of kinematical requirements are imposed by means of a neural network algorithm. At least one of these jets must be identified as initiated by a b-quark candidate by the reconstruction of a secondary vertex. The cross section is measured to be sigma_{tt}=8.3+-1.0(stat.)+2.0-1.5(syst.)+-0.5(lumi.) pb, which is consistent with the standard model prediction. The top quark mass of 174.0+-2.2(stat.)+-4.8(syst.) GeV/c^2 is derived from a likelihood fit incorporating reconstructed mass distributions representative of signal and background.

hep-ex↗
arXiv2007

Limits on Anomalous Triple Gauge Couplings in ppbar Collisions at sqrt{s}=1.96 TeV

We present a search for anomalous triple gauge couplings (ATGC) in WW and WZ boson production. The boson pairs are produced in ppbar collisions at sqrt{s}=1.96 TeV, and the data sample corresponds to 350 pb-1 of integrated luminosity collected with the CDF II detector at the Fermilab Tevatron. In this search one W decays to leptons, and the other boson (W or Z) decays hadronically. Combining with a previously published CDF measurement of Wgamma boson production yields ATGC limits of -0.18 < lambda < 0.17 and -0.46 < Delta kappa < 0.39 at the 95% confidence level, using a cut-off scale Lambda=1.5 TeV.

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arXiv2007

First Run II Measurement of the W Boson Mass

We describe a measurement of the W boson mass mW using 200/pb of root-s = 1.96 TeV p-pbar collision data taken with the CDF II detector. With a sample of 63,964 W -> e nu candidates and 51,128 W -> mu nu candidates, we measure mW = [80.413 +- 0.034 (stat) +- 0.034 (sys) = 80.413 +- 0.048] GeV/c^2. This is the single most precise mW measurement to date. When combined with other measured electroweak parameters, this result further constrains the properties of unobserved particles coupling to W and Z bosons.

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arXiv2007

Search for New Physics in High Mass Electron-Positron Events in ppbar Collisions at sqrt(s) = 1.96 TeV

We report the results of a search for a narrow resonance in electron-positron events in the invariant mass range of 150-950 GeV/c^2 using 1.3 fb^-1 of ppbar collision data at sqrt(s) = 1.96 TeV collected by the CDF II detector at Fermilab. No significant evidence of such a resonance is observed and we interpret the results to exclude the standard model-like Z' with a mass below 923 GeV/c^2 and the Randall-Sundrum graviton with a mass below 807 GeV/c^2 for k/M_pl=0.1, both at the 95% confidence level. Combining with di-photon data excludes the Randall-Sundrum graviton for masses below 889 GeV/c^2 for k/M_pl=0.1.

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