CDF Collaboration(Aaltonen, T. et al), & Cabrera, S. (2010). Search for single top quark production in p(p)over-bar collisions at root s=1.96 TeV in the missing transverse energy plus jets topology. Phys. Rev. D, 81(7), 072003–24pp.
Abstract: We report a search for single top quark production with the CDF II detector using 2: 1 fb(-1) of integrated luminosity of p (p) over bar collisions at root s = 1.96 TeV. The data selected consist of events characterized by large energy imbalance in the transverse plane and hadronic jets, and no identified electrons and muons, so the sample is enriched in W -> tau nu decays. In order to suppress backgrounds, additional kinematic and topological requirements are imposed through a neural network, and at least one of the jets must be identified as a b quark jet. We measure an excess of signal-like events in agreement with the standard model prediction, but inconsistent with a model without single top quark production by 2.1 standard deviations (sigma), with a median expected sensitivity of 1.4 sigma. Assuming a top quark mass of 175 GeV/c(2) and ascribing the excess to single top quark production, the cross section is measured to be 4.9(-2.2)(+2.5) (stat + syst) pb, consistent with measurements performed in independent data sets and with the standard model prediction.
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CDF Collaboration(Aaltonen, T. et al), & Cabrera, S. (2010). Search for R-Parity Violating Decays of Sneutrinos to e mu, μtau, and e tau Pairs in p(p)over-bar Collisions at root s=1.96 TeV. Phys. Rev. Lett., 105(19), 191801–7pp.
Abstract: We present a search for supersymmetric neutrino (nu) over tilde production using the Tevatron p (p) over bar collision data collected with the CDF II detector and corresponding to an integrated luminosity of 1 fb(-1). We focus on the scenarios predicted by the R-parity violating (RPV) supersymmetric models in which sneutrinos decay to two charged leptons of different flavor. With the data consistent with the standard model expectations, we set upper limits on sigma(p (p) over bar -> (nu) over tilde) BR((nu) over tilde -> e mu, μtau, e tau) and use these results to constrain the RPV couplings as a function of the sneutrino mass.
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CDF Collaboration(Aaltonen, T. et al), Cabrera, S., & Cuenca Almenar, C. (2010). Search for Pair Production of Supersymmetric Top Quarks in Dilepton Events from p(p)over-bar Collisions at root s=1.96 TeV. Phys. Rev. Lett., 104(25), 251801–8pp.
Abstract: We present the results of a search for pair production of the supersymmetric partner of the top quark (the top squark (t) over tilde (1)) decaying to a b quark and a chargino (chi) over tilde (+/-)(1) with a subsequent (chi) over tilde (+/-)(1) decay into a neutralino (chi) over tilde (0)(1), lepton l, and neutrino nu Using a data sample corresponding to 2.7 fb(-1) of integrated luminosity of p (p) over bar collisions at root s = 1: 96 TeV collected by the CDF II detector, we reconstruct the mass of top squark candidate events and fit the observed mass spectrum to a combination of standard model processes and (t) over tilde (1)(t) over tilde (1). We find no evidence for (t) over tilde (1)(t) over tilde (1) production and set 95% C. L. limits on the masses of the top squark and the neutralino for several values of the chargino mass and the branching ratio B((X) over tilde (+/-)(1) -> (chi) over tilde (0)(1)l(+/-)nu).
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CDF Collaboration(Aaltonen, T. et al), & Cabrera, S. (2010). Search for New Physics with a Dijet Plus Missing E-T Signature in p(p)over-bar Collisions at root s=1.96 TeV. Phys. Rev. Lett., 105(13), 131801–8pp.
Abstract: We 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.
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CDF Collaboration(Aaltonen, T. et al), & Cabrera, S. (2010). Search for new color-octet vector particle decaying to t(t)over-bar in p(p)over-bar collisions at root s=1.96 TeV. Phys. Lett. B, 691(4), 183–190.
Abstract: We present the result of a search for a massive color-octet vector particle, (e.g. a massive gluon) decaying to a pair of top quarks in proton-antiproton collisions with a center-of-mass energy of 1.96 TeV. This search is based on 1.9 fb(-1) of data collected using the CDF detector during Run II of the Tevatron at Fermilab. We study t (t) over bar events in the lepton + jets channel with at least one b-tagged jet. A massive gluon is characterized by its mass, decay width, and the strength of its coupling to quarks. These parameters are determined according to the observed invariant mass distribution of top quark pairs. We set limits on the massive gluon coupling strength for masses between 400 and 800 GeV/c(2) and width-to-mass ratios between 0.05 and 0.50. The coupling strength of the hypothetical massive gluon to quarks is consistent with zero within the explored parameter space.
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CDF Collaboration(Aaltonen, T. et al), & Cabrera, S. (2010). Search for New Bottomlike Quark Pair Decays Q(Q)over-bar -> (tW +/-)((t)over-barW +/- in Same-Charge Dileption Events. Phys. Rev. Lett., 104(9), 091801–8pp.
Abstract: We report the most restrictive direct limits on masses of fourth- generation down- type quarks b0, and quarklike composite fermions (B or T5= 3), decaying promptly to tW -/+. We search for a significant excess of events with two same- charge leptons (e, mu), several hadronic jets, and missing transverse energy. An analysis of data from pp collisions with an integrated luminosity of 2: 7 fb = 1 collected with the CDF II detector at Fermilab yields no evidence for such a signal, setting mass limits mb0, mB > 338 GeV= c2 and mT5= 3 > 365 GeV= c2 at 95% confidence level.
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CDF Collaboration(Aaltonen, T. et al), & Cabrera, S. (2010). Search for anomalous production of events with two photons and additional energetic objects at CDF. Phys. Rev. D, 82(5), 052005–27pp.
Abstract: We present results of a search for anomalous production of two photons together with an electron, muon, tau lepton, missing transverse energy, or jets using p (p) over bar collision data from 1.1-2.0 fb(-1) of integrated luminosity collected by the Collider Detector at Fermilab (CDF). The event yields and kinematic distributions are examined for signs of new physics without favoring a specific model of new physics. The results are consistent with the standard model expectations. The search employs several new analysis
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CDF Collaboration(Aaltonen, T. et al), & Cabrera, S. (2011). Search for a Very Light CP-Odd Higgs Boson in Top Quark Decays from p p-bar Collisions at sqrt(s)=1.96 TeV. Phys. Rev. Lett., 107(3), 031801–8pp.
Abstract: 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).
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CDF Collaboration(Aaltonen, T. et al), & Cabrera, S. (2011). Search for a Heavy Toplike Quark in p p-bar Collisions at sqrt(s)=1.96 TeV. Phys. Rev. Lett., 107(26), 261801–8pp.
Abstract: We present the results of a search for pair production of a heavy toplike (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 p (p) over bar collisions at root s = 1.96 TeV. We perform parallel searches for t' -> Wb and t' -> 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'(t) over bar' production cross section and exclude a standard model fourth-generation t' quark decaying to Wb (Wq) with mass below 358 (340) GeV/c(2) at 95% C. L.
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CDF Collaboration(Aaltonen, T. et al), & Cabrera, S. (2012). Production of Lambda(0), (Lambda)over-bar(0), Xi(+/-), and Omega(+/-) hyperons in p(p)over-bar collisions at root s=1.96 TeV. Phys. Rev. D, 86(1), 012002–10pp.
Abstract: We report a set of measurements of inclusive invariant p(T) differential cross sections of Lambda(0), (Lambda) over bar (0), Xi(+/-), and Omega(+/-) hyperons reconstructed in the central region with pseudorapidity vertical bar eta vertical bar < 1 and p(T) up to 10 GeV/c. Events are collected with a minimum-bias trigger in p<(p)over bar> collisions at a center-of-mass energy of 1.96 TeV using the CDF II detector at the Tevatron Collider. As p(T) increases, the slopes of the differential cross sections of the three particles are similar, which could indicate a universality of the particle production in p(T). The invariant differential cross sections are also presented for different charged-particle multiplicity intervals.
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