We report on a search for charged massive resonances decaying to top (t) and bottom (b) quarks in the full data set of proton-antiproton collisions at a center-of-mass energy of √s=1.96 TeV ...collected by the CDF II detector at the Tevatron, corresponding to an integrated luminosity of 9.5 fb(-1). No significant excess above the standard model background prediction is observed. We set 95% Bayesian credibility mass-dependent upper limits on the heavy charged-particle production cross section times branching ratio to tb. Using a standard model extension with a W'→tb and left-right-symmetric couplings as a benchmark model, we constrain the W' mass and couplings in the 300-900 GeV/c(2) range. The limits presented here are the most stringent for a charged resonance with mass in the range 300-600 GeV/c(2) decaying to top and bottom quarks.
(ProQuest: ... denotes formulae and/or non-USASCII text omitted) We measure the forward-backward asymmetry of the production of top-quark and antiquark pairs in proton-antiproton collisions at ...center-of-mass energy radicals=1.96 TeV using the full data set collected by the Collider Detector at Fermilab (CDF) in Tevatron Run II corresponding to an integrated luminosity of 9.1 fb super(-1). The asymmetry is characterized by the rapidity difference between top quarks and antiquarks (Deltay) and measured in the final state with two charged leptons (electrons and muons). The inclusive asymmetry, corrected to the entire phase space at parton level, is measured to be ..., consistent with the expectations from the standard model (SM) and previous CDF results in the final state with a single charged lepton. The combination of the CDF measurements of the inclusive ... in both final states yields ..., which is consistent with the SM predictions. We also measure the differential asymmetry as a function of Deltay. A linear fit to ..., assuming zero asymmetry at Deltay=0, yields a slope of alpha=0.14+ or -0.15, consistent with the SM prediction and the previous CDF determination in the final state with a single charged lepton. The combined slope of ... in the two final states is alpha=0.227+ or -0.057, which is 2.0sigma larger than the SM prediction.
Memristive devices have been a hot topic in nanoelectronics for the last two decades in both academia and industry. Originally proposed as digital (binary) nonvolatile random access memories, ...research in this field was predominantly driven by the search for higher performance solid-state drive technologies (e.g., flash replacement) or higher density memories (storage class memory). However, based on their large dynamic range in resistance with analog-tunability along with complex switching dynamics, memristive devices enable revolutionary novel functions and computing paradigms. We present the prospects, opportunities, and materials challenges of memristive devices in computing applications, both near and far terms. Memristive devices offer at least three main types of novel computing applications: in-memory computing, analog computing, and state dynamics. We will present the status in the understanding of the most common redox-based memristive devices while addressing the challenges that materials research will need to tackle in the future. In order to pave the way toward novel computing paradigms, a rational design of the materials stacks will be required, enabling nanoscale control over the ionic dynamics that gives these devices their variety of capabilities.
The first observation of the production of a W boson with a single charm quark (c) jet in ppover ¯ collisions at √s=1.96 TeV is reported. The analysis uses data corresponding to 4.3 fb(-1), ...recorded with the CDF II detector at the Fermilab Tevatron. Charm quark candidates are selected through the identification of an electron or muon from charm-hadron semileptonic decay within a hadronic jet, and a Wc signal is observed with a significance of 5.7 standard deviations. The production cross section σ(Wc)(p(Tc)>20 GeV/c,|η(c)|<1.5)×B(W→ℓν) is measured to be 13.6(-3.1)(+3.4) pb and is in agreement with theoretical expectations. From this result the magnitude of the quark-mixing matrix element V(cs) is derived, |V(cs)|=1.08±0.16 along with a lower limit of |V(cs)|>0.71 at the 95% confidence level, assuming that the Wc production through c to s quark coupling is dominant.
A search for a Higgs boson with suppressed couplings to fermions, h sub(functionof), assumed to be the neutral, lower-mass partner of the Higgs boson discovered at the Large Hadron Collider, is ...reported. Such a Higgs boson could exist in extensions of the standard model with two Higgs doublets, and could be produced via pparrowright H super(+ or -)h sub(functionof)arrowright W* super(h) sub(functionof)h sub(functionof)arrowright 4gamma + X, where H super(+ or -) is a charged Higgs boson. This analysis uses all events with at least three photons in the final state from proton-antiproton collisions at a center-of-mass energy of 1.96 TeV collected by the Collider Detector at Fermilab, corresponding to an integrated luminosity of 9.2fb super(-1). No evidence of a signal is observed in the data. Values of Higgs-boson masses between 10 and 100GeV/c super(2) are excluded at 95% Bayesian credibility.
We report on a measurement of the D+-meson production cross section as a function of transverse momentum (pT) in proton-antiproton (pp¯) collisions at 1.96 TeV center-of-mass energy, using the full ...data set collected by the Collider Detector at Fermilab in Tevatron Run II and corresponding to 10 fb−1 of integrated luminosity. We use D+→K−π+π+ decays fully reconstructed in the central rapidity region |y|<1 with transverse momentum down to 1.5 GeV/c, a range previously unexplored in pp¯ collisions. Inelastic pp¯-scattering events are selected online using minimally biasing requirements followed by an optimized offline selection. The K−π+π+ mass distribution is used to identify the D+ signal, and the D+ transverse impact-parameter distribution is used to separate prompt production, occurring directly in the hard-scattering process, from secondary production from b-hadron decays. We obtain a prompt D+ signal of 2950 candidates corresponding to a total cross section σ(D+,1.5<pT<14.5 GeV/c,|y|<1)=71.9±6.8(stat)±9.3(syst) μb. While the measured cross sections are consistent with theoretical estimates in each pT bin, the shape of the observed pT spectrum is softer than the expectation from quantum chromodynamics. The results are unique in pp¯ collisions and can improve the shape and uncertainties of future predictions.
The Collider Detector at Fermilab collected a unique sample of jets originating from bottom-quark fragmentation (b-jets) by selecting online proton-antiproton (pp¯) collisions with a vertex displaced ...from the pp¯ interaction point, consistent with the decay of a bottom-quark hadron. This data set, collected at a center-of-mass energy of 1.96 TeV, and corresponding to an integrated luminosity of 5.4 fb−1, is used to measure the Z-boson production cross section times branching ratio into bb¯. The number of Z→bb¯ events is determined by fitting the dijet-mass distribution, while constraining the dominant b-jet background, originating from QCD multijet events, with data. The result, σ(pp¯→Z)×B(Z→bb¯)=1.11±0.08(stat)±0.14(syst) nb, is the most precise measurement of this process, and is consistent with the standard-model prediction. The data set is also used to search for Higgs-boson production. No significant signal is expected in our data and the first upper limit on the cross section for the inclusive pp¯→H→bb¯ process at s=1.96 TeV is set, corresponding to 33 times the expected standard-model cross section, or σ=40.6 pb, at the 95% confidence level.
We present a search for the standard model Higgs boson produced in association with a Z boson in data collected with the CDF II detector at the Tevatron, corresponding to an integrated luminosity of ...9.45 fb(-1). In events consistent with the decay of the Higgs boson to a bottom-quark pair and the Z boson to electron or muon pairs, we set 95% credibility level upper limits on the ZH production cross section times the H→bb branching ratio as a function of Higgs boson mass. At a Higgs boson mass of 125 GeV/c(2), we observe (expect) a limit of 7.1 (3.9) times the standard model value.
The top-quark mass M sub(top) is measured using top quark-antiquark pairs produced in proton-antiproton collisions at a center-of-mass energy of 1.96 TeV and that decay into a fully hadronic final ...state. The full data set collected with the CDF II detector at the Fermilab Tevatron Collider, corresponding to an integrated luminosity of 9.3 fb super(-1), is used. Events are selected that have six to eight jets, at least one of which is identified as having originated from a b quark. In addition, a multivariate algorithm, containing multiple kinematic variables as inputs, is used to discriminate signal events from background events due to QCD multijet production. Templates for the reconstructed top-quark mass are combined in a likelihood fit to measure M sub(top) with a simultaneous calibration of the jet energy scale. A value of M sub(top) = 175.07 + or - 1.19(stat) (ProQuest: Formulae and/or non-USASCII text omitted)(syst) GeV /c super(2) is obtained for the top-quark mass.
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