48 research outputs found

    Measurement of the Forward-Backward Asymmetry in the B -> K(*) mu+ mu- Decay and First Observation of the Bs -> phi mu+ mu- Decay

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    We reconstruct the rare decays B+K+μ+μB^+ \to K^+\mu^+\mu^-, B0K(892)0μ+μB^0 \to K^{*}(892)^0\mu^+\mu^-, and Bs0ϕ(1020)μ+μB^0_s \to \phi(1020)\mu^+\mu^- in a data sample corresponding to 4.4fb14.4 {\rm fb^{-1}} collected in ppˉp\bar{p} collisions at s=1.96TeV\sqrt{s}=1.96 {\rm TeV} by the CDF II detector at the Fermilab Tevatron Collider. Using 121±16121 \pm 16 B+K+μ+μB^+ \to K^+\mu^+\mu^- and 101±12101 \pm 12 B0K0μ+μB^0 \to K^{*0}\mu^+\mu^- decays we report the branching ratios. In addition, we report the measurement of the differential branching ratio and the muon forward-backward asymmetry in the B+B^+ and B0B^0 decay modes, and the K0K^{*0} longitudinal polarization in the B0B^0 decay mode with respect to the squared dimuon mass. These are consistent with the theoretical prediction from the standard model, and most recent determinations from other experiments and of comparable accuracy. We also report the first observation of the Bs0ϕμ+μdecayandmeasureitsbranchingratioB^0_s \to \phi\mu^+\mu^- decay and measure its branching ratio {\mathcal{B}}(B^0_s \to \phi\mu^+\mu^-) = [1.44 \pm 0.33 \pm 0.46] \times 10^{-6}using using 27 \pm 6signalevents.Thisiscurrentlythemostrare signal events. This is currently the most rare B^0_s$ decay observed.Comment: 7 pages, 2 figures, 3 tables. Submitted to Phys. Rev. Let

    Search for a New Heavy Gauge Boson Wprime with Electron + missing ET Event Signature in ppbar collisions at sqrt(s)=1.96 TeV

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    We present a search for a new heavy charged vector boson WW^\prime decaying to an electron-neutrino pair in ppˉp\bar{p} collisions at a center-of-mass energy of 1.96\unit{TeV}. The data were collected with the CDF II detector and correspond to an integrated luminosity of 5.3\unit{fb}^{-1}. No significant excess above the standard model expectation is observed and we set upper limits on σB(Weν)\sigma\cdot{\cal B}(W^\prime\to e\nu). Assuming standard model couplings to fermions and the neutrino from the WW^\prime boson decay to be light, we exclude a WW^\prime boson with mass less than 1.12\unit{TeV/}c^2 at the 95\unit{%} confidence level.Comment: 7 pages, 2 figures Submitted to PR

    Measurements of the properties of Lambda_c(2595), Lambda_c(2625), Sigma_c(2455), and Sigma_c(2520) baryons

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    We report measurements of the resonance properties of Lambda_c(2595)+ and Lambda_c(2625)+ baryons in their decays to Lambda_c+ pi+ pi- as well as Sigma_c(2455)++,0 and Sigma_c(2520)++,0 baryons in their decays to Lambda_c+ pi+/- final states. These measurements are performed using data corresponding to 5.2/fb of integrated luminosity from ppbar collisions at sqrt(s) = 1.96 TeV, collected with the CDF II detector at the Fermilab Tevatron. Exploiting the largest available charmed baryon sample, we measure masses and decay widths with uncertainties comparable to the world averages for Sigma_c states, and significantly smaller uncertainties than the world averages for excited Lambda_c+ states.Comment: added one reference and one table, changed order of figures, 17 pages, 15 figure

    Mu2e Technical Design Report

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    The Mu2e experiment at Fermilab will search for charged lepton flavor violation via the coherent conversion process mu- N --> e- N with a sensitivity approximately four orders of magnitude better than the current world's best limits for this process. The experiment's sensitivity offers discovery potential over a wide array of new physics models and probes mass scales well beyond the reach of the LHC. We describe herein the preliminary design of the proposed Mu2e experiment. This document was created in partial fulfillment of the requirements necessary to obtain DOE CD-2 approval.Comment: compressed file, 888 pages, 621 figures, 126 tables; full resolution available at http://mu2e.fnal.gov; corrected typo in background summary, Table 3.

    Binary systems and their nuclear explosions

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    Peer ReviewedPreprin

    Search for heavy bottom-like quarks decaying to an electron or muon and jets in ppˉp\bar{p} collisions at s=1.96\sqrt{s}=1.96 TeV

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    We report the most sensitive direct search for pair production of fourth-generation bottom-like chiral quarks (bb') each decaying promptly to tWtW. We search for an excess of events with an electron or muon, at least five jets (one indentified as due to a bb or cc quark) and an imbalance of transverse momentum using data from ppˉp\bar{p} collisions collected by the CDF II detector at Fermilab with an integrated luminosity of 4.8 fb1^{-1}. We observe events consistent with background expectation and calculate upper limits on the bb' pair production cross section (σbbˉ30\sigma_{b\bar{b'}}\lesssim 30 fb for mb>m_{b'}>375 GeV/c2c^2) and exclude mb<372m_{b'}<372 \gevcc at 95% confidence level.Comment: For submission to PR

    First Measurement of the Angular Coefficients of Drell-Yan e(+)e(-) Pairs in the Z Mass Region from p(p)over-bar Collisions at root s=1.96 TeV

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    We report on the first measurement of the angular distributions of final state electrons in p (p) over bar -> gamma*/Z -> e(+)e(-) + X events produced in the Z boson mass region at root s = 1.96 TeV. The data sample collected by the CDF II detector for this result corresponds to 2.1 fb(-1) of integrated luminosity. The angular distributions are studied as a function of the transverse momentum of the electron-positron pair and show good agreement with the Lam-Tung relation, consistent with a spin-1 description of the gluon, and demonstrate that, at high values of the transverse momentum, Z bosons are produced via quark-antiquark annihilation and quark-gluon Compton processes

    Search for a Very Light CP-Odd Higgs Boson in Top Quark Decays from p(p)over-bar Collisions at root s=1.96 TeV

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    We present the results of a search for a very light CP-odd Higgs boson a(1)(0) originating from top quark decays t -> H(+/-)b -> W-+/-(*) a(1)(0)b, and subsequently decaying into tau(+)tau(-). Using a data sample corresponding to an integrated luminosity of 2.7 fb(-1) collected by the CDF II detector in p (p) over bar collisions at 1.96 TeV, we perform a search for events containing a lepton, three or more jets, and an additional isolated track with transverse momentum in the range 3 to 20 GeV/c. Observed events are consistent with background sources, and 95% C.L. limits are set on the branching ratio of t -> H(+/-)b for various masses of H-+/- and a(1)(0)

    First Search for Multijet Resonances in root s=1.96 TeV p(p)over-bar Collisions

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    We present the first model independent search for three-jet hadronic resonances within multijet events in root s = 1.96 TeV p (p) over bar collisions at the Fermilab Tevatron using the CDF II detector. Pair production of supersymmetric gluinos and squarks with hadronic R-parity violating decays is employed as an example of a new physics benchmark for this signature. Selection criteria based on the kinematic properties of an ensemble of jet combinations within each event help to extract signal from copious QCD background. No significant excess outside the top quark mass window is observed in data with an integrated luminosity of 3.2 fb(-1). We place 95% confidence level limits on the production cross section sigma(p (p) over bar -> XX') X BR((g) over tilde(g) over tilde -> 3 jet + 3 jet) where X, X' = (g) over tilde, (q) over tilde, or (sic), with (q) over tilde, (sic) -> (g) over tilde + jet, as a function of gluino mass, in the range of 77 GeV/c(2) to 240 GeV/c(2)

    Reducing Humidity Response of Gas Sensors for Medical Applications: Use of Spark Discharge Synthesis of Metal Oxide Nanoparticles

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    The application of gas sensors in breath analysis is an important trend in the early diagnostics of different diseases including lung cancer, ulcers, and enteric infection. However, traditional methods of synthesis of metal oxide gas-sensing materials for semiconductor sensors based on wet sol-gel processes give relatively high sensitivity of the gas sensor to changing humidity. The sol-gel process leading to the formation of superficial hydroxyl groups on oxide particles is responsible for the strong response of the sensing material to this factor. In our work, we investigated the possibility to synthesize metal oxide materials with reduced sensitivity to water vapors. Dry synthesis of SnO2 nanoparticles was implemented in gas phase by spark discharge, enabling the reduction of the hydroxyl concentration on the surface and allowing the production of tin dioxide powder with specific surface area of about 40 m2/g after annealing at 610 &deg;C. The drop in sensor resistance does not exceed 20% when air humidity increases from 40 to 100%, whereas the response to 100 ppm of hydrogen is a factor of 8 with very short response time of about 1 s. The sensor response was tested in mixtures of air with hydrogen, which is the marker of enteric infections and the marker of early stage fire, and in a mixture of air with lactate (marker of stomach cancer) and ammonia gas (marker of Helicobacter pylori, responsible for stomach ulcers)
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