48 research outputs found
Measurement of the ratios of branching fractions B (B-s(0)-> D-s(-) pi(+) pi(+) pi(-))/B(B-0 -> D- pi(+) pi(+) pi(-)) and B(B-s(0) -> D-s(-) pi(+))/B(B-0 -> D- pi(+))
No full textUsing 355 pb(-1) of data collected by the CDF II detector in p (p) over bar at collisions at root s = 1.96 TeV at the Fermilab Tevatron, we study the fully reconstructed hadronic decays B-(s)(0) -> D-(s)(-)pi(+) and B-(s)(0) -> D-(s)(-) pi(+)pi(+)pi(-). We present the first measurement of the ratio of branching fractions B(B-s(0) -> D-s(-) pi(+)pi(+)pi(-))/B(B-0 -> D-s(-) pi(+)pi(+)pi(-)) = 1.05 +/- 0.10(stat) +/- 0.22(syst). We also update our measurement of B(B-s(0) -> D-s(-)pi(+))/B(B-0 -> D-pi(+)) to 1.13 +/- 0.08(stat) +/- 0.23(syst), improving the statistical uncertainty by more than a factor of 2. We find B(B-s(0) -> D-s(-)pi(+)) = [3.8 +/- 0.3(stat) +/- 1.3(syst)] x 10(-3) and B(B-s(0) -> D-s(-) pi(+)pi(+)pi(-)) = [8.4 +/- 0.8 (stat) +/- 3.2(syst)] x 10(-3)
Updated search for the flavor-changing neutral-current decay D0 -> mu+ mu- collisions at sqrt(s)=1.96 TeV
No full textWe report on a search for the flavor-changing neutral-current decay D0 \to {\mu}+ {\mu}- in pp collisions at \surd s = 1.96 TeV using 360 pb-1 of integrated luminosity collected by the CDF II detector at the Fermilab Tevatron collider. A displaced vertex trigger selects long-lived D0 candidates in the {\mu}+ {\mu}-, {\pi}+{\pi}-, and K-{\pi}+ decay modes. We use the Cabibbo-favored D0 \to K-{\pi}+ channel to optimize the selection criteria in an unbiased manner, and the kinematically similar D0 \to{\pi}+ {\pi}- channel for normalization. We set an upper limit on the branching fraction (D0 --> {\mu}+ {\mu}-)We report on a search for the flavor-changing neutral-current decay D0→μ+μ- in pp̅ collisions at √s=1.96 TeV using 360 pb-1 of integrated luminosity collected by the CDF II detector at the Fermilab Tevatron collider. A displaced vertex trigger selects long-lived D0 candidates in the μ+μ-, π+π-, and K-π+ decay modes. We use the Cabibbo-favored D0→K-π+ channel to optimize the selection criteria in an unbiased manner, and the kinematically similar D0→π+π- channel for normalization. We set an upper limit on the branching fraction B(D0→μ+μ-)<2.1×10-7(3.0×10-7) at the 90% (95%) confidence level.Peer reviewe
Measurement of the inclusive jet cross section in p(p)over-bar interactions at root S=1.96 TeV using a cone-based jet algorithm
No full textWe present a measurement of the inclusive jet cross section in p (p) over bar interactions at root s\u3e=1.96 TeV using 385 pb(-1) of data collected with the CDF II detector at the Fermilab Tevatron. The results are obtained using an improved cone-based jet algorithm (Midpoint). The data cover the jet transverse momentum range from 61 to 620 GeV/c, extending the reach by almost 150 GeV/c compared with previous measurements at the Tevatron. The results are in good agreement with next-to-leading order perturbative QCD predictions using the CTEQ6.1M parton distribution functions
Study of the associated production of photons and b-quark jets in p(p)over-bar collisions at root s=1.96 TeV
No full textThe cross section for photon production in association with at least one jet containing a b quark has been measured in proton antiproton collisions at root s = 1.96 TeV. The data sample used corresponds to an integrated luminosity of 340 pb(-1) collected with the CDF II detector. Both the differential cross section as a function of photon transverse energy E-T(gamma) and the total cross section are measured and compared to a next-to-leading order prediction for the process
Search for the Production of Scalar Bottom Quarks in p(p)over-bar Collisions at root s=1.96 TeV
No full textWe report on a search for direct scalar bottom quark (sbottom) pair production in p (p) over bar collisions at root s = 1.96 TeV, in events with large missing transverse energy and two jets of hadrons in the final state, where at least one of the jets is required to be identified as originating from a b quark. The study uses a collider detector at Fermilab Run II data sample corresponding to 2.65 fb(-1) of integrated luminosity. The data are in agreement with the standard model. In an R-parity conserving minimal supersymmetric scenario, and assuming that the sbottom decays exclusively into a bottom quark and a neutralino, 95% confidence-level upper limits on the sbottom pair production cross section of 0.1 pb are obtained. For neutralino masses below 70 GeV/c(2), sbottom masses up to 230 GeV/c(2) are excluded at 95% confidence level
Search for neutral Higgs bosons of the minimal supersymmetric standard model decaying to tau pairs in p(p)over-bar collisions at root s=1.96 TeV
No full textWe present a search for neutral supersymmetric Higgs bosons decaying to tau pairs produced in p (p) over bar collisions at root s=1.96 TeV. The data, corresponding to 310 pb(-1) integrated luminosity, were collected with the Collider Detector at Fermilab in run II of the Tevatron. No significant excess above the standard model backgrounds is observed. We set exclusion limits on the production cross section times branching fraction to tau pairs for Higgs boson masses in the range from 90 to 250 GeV/c(2)
Search for a Heavy Top-Like Quark in p\bar{p} Collisions at {\surd}s = 1.96 TeV
No full textWe present the results of a search for pair production of a heavy top-like (t') quark decaying to Wq final states using data corresponding to an integrated luminosity of 5.6 fb-1 collected by the CDF II detector in pp collisions at {\surd}s = 1.96 TeV. We perform parallel searches for t' \to Wb and t' \to Wq (where q is a generic down-type quark) in events containing a lepton and four or more jets. By performing a fit to the two-dimensional distribution of total transverse energy versus reconstructed t quark mass, we set upper limits on the t \bar{t} production cross section and exclude a standard model fourth-generation t' quark decaying to W b (W q) with mass below 358 (340) GeV/c2 at 95% CL
Search for New Physics with a Dijet Plus Missing E-T Signature in p(p)over-bar Collisions at root s=1.96 TeV
No full textWe present results of a signature-based search for new physics using a dijet plus missing transverse energy (E-T) data sample collected in 2 fb(-1) of p (p) over bar collisions at root s = 1.96 TeV with the CDF II detector at the Fermilab Tevatron. We observe no significant event excess with respect to the standard model prediction and extract a 95% C. L. upper limit on the cross section times acceptance for a potential contribution from a nonstandard model process. The search is made by using novel, data-driven techniques for estimating backgrounds that are applicable to first searches at the LHC
Measurement of the tt̅ production cross section in pp̅ collisions at √s=1.96 TeV using soft electron b-tagging
No full textWe present a measurement of the top-quark pair-production cross section in pp̅ collisions at [sqrt]s=1.96 TeV using a data sample corresponding to 1.7 fb-1 of integrated luminosity collected with the Collider Detector at Fermilab. We reconstruct tt̅ events in the lepton+jets channel, consisting of eν+jets and μν+jets final states. The dominant background is the production of W bosons in association with multiple jets. To suppress this background, we identify electrons from the semileptonic decay of heavy-flavor jets (“soft electron tags”). From a sample of 2196 candidate events, we obtain 120 tagged events with a background expectation of 51±3 events, corresponding to a cross section of σtt̅ =7.8±2.4(stat)±1.6(syst)±0.5(lumi) pb. We assume a top-quark mass of 175 GeV/c2. This is the first measurement of the tt̅ cross section with soft electron tags in run II of the Tevatron.United States Department of EnergyNational Science FoundationIstituto Nazionale di Fisica Nucleare of ItalyMinistry of Education, Culture, Sports, Science and Technology of JapanNatural Sciences and Engineering Research Council of CanadaNational Science Council of the Republic of ChinaSwiss National Science FoundationAlfred P. Sloan FoundationBundesministerium für Bildung und Forschung, GermanyWorld Class University Program (Korea)National Research Foundation of KoreaScience and Technology Facilities Council, United KingdomInstitut National de Physique Nucleaire et Physique des Particules/CNRSRussian Foundation for Basic ResearchMinisterio de Ciencia e Innovación, SpainPrograma Consolider-Ingenio 2010, SpainSlovak R&D AgencyAcademy of Finlan
Search for new heavy particles decaying to Z(0)Z(0)-> eeee in p(p)over-bar collisions at root s=1.96 TeV
No full textWe report the results of a search for the anomalous production of a massive particle decaying to four electrons via two Z0 bosons in 1.1fb-1 of pp̄ collisions at s=1.96TeV collected by the CDF II detector at Fermilab. We employ optimized electron identification criteria to maximize acceptance and efficiency. We estimate the backgrounds in the invariant mass range 500-1000GeV/c2 to be 0.028±0.009(stat)±0.011(syst) events. We observe zero events in this search region. Assuming a Randall-Sundrum graviton production model, we set 95% C.L. limits on σ×BF(G→Z0Z0)<4- 6pb, depending on the graviton mass. © 2008 The American Physical Society
