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). Study of the associated production of photons and b-quark jets in p(p)over-bar collisions at root s=1.96 TeV. Phys. Rev. D, 81(5), 052006–8pp.
Abstract: The 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.
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CDF Collaboration(Aaltonen, T. et al), & Cabrera, S. (2010). Measurement of the top quark mass and p(p)over-bar -> t(t)over-bar cross section in the all-hadronic mode with the CDF II detector. Phys. Rev. D, 81(5), 052011–20pp.
Abstract: We present a measurement of the top quark mass and of the top-antitop (t (t) over bar) pair production cross section using p (p) over bar data collected with the CDF II detector at the Tevatron Collider at the Fermi National Accelerator Laboratory and corresponding to an integrated luminosity of 2.9 fb(-1). We select events with six or more jets satisfying a number of kinematical requirements imposed by means of a neural-network algorithm. At least one of these jets must originate from a b quark, as identified by the reconstruction of a secondary vertex inside the jet. The mass measurement is based on a likelihood fit incorporating reconstructed mass distributions representative of signal and background, where the absolute jet energy scale ( JES) is measured simultaneously with the top quark mass. The measurement yields a value of 174.8 +/- 2.4(stat + JES)(-1.0)(+1.2)(syst) GeV/c(2), where the uncertainty from the absolute jet energy scale is evaluated together with the statistical uncertainty. The procedure also measures the amount of signal from which we derive a cross section, sigma(t (t$) over bar) = 7.2 +/- 0.5(stat) +/- 1.0(syst) +/- 0.4(lum) pb, for the measured values of top quark mass and JES.
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CDF Collaboration(Aaltonen, T. et al), & Cabrera, S. (2010). Measurement of the top quark mass in the dilepton channel using m(T2) at CDF. Phys. Rev. D, 81(3), 031102–9pp.
Abstract: We present measurements of the top quark mass using m(T2), a variable related to the transverse mass in events with two missing particles. We use the template method applied to t (t) over bar dilepton events produced in p (p) over bar collisions at Fermilab's Tevatron Collider and collected by the CDF detector. From a data sample corresponding to an integrated luminosity of 3.4 fb(-1), we select 236 t (t) over bar candidate events. Using the m(T2) distribution, we measure the top quark mass to be M-top = 168.0(-4.0)(4.8)(stat) +/- 2.9(syst) GeV/c(2). By combining m(T2) with the reconstructed top quark mass distributions based on a neutrino weighting method, we measure M-top = 169.3 +/- 2.7(stat) +/- 3.2(syst) GeV/c(2). This is the first application of the m(T2) variable in a mass measurement at a hadron collider.
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CDF Collaboration(Aaltonen, T. et al), & Cabrera, S. (2010). Measurements of branching fraction ratios and CP asymmetries in B-+/- -> DCPK +/- decays in hadron collisions. Phys. Rev. D, 81(3), 031105–9pp.
Abstract: We reconstruct B-+/- -> DK +/- decays in a data sample collected by the CDF II detector at the Tevatron collider corresponding to 1 fb(-1) of integrated luminosity. We select decay modes where the D meson decays to either K-pi(+) (flavor eigenstate) or K-K+, pi(-)pi(+) (CP-even eigenstates), and measure the direct CP asymmetry A(CP+) = 0.39 +/- 0.17(stat) +/- 0.04(syst), and the double ratio of CP-even to flavor eigenstate branching fractions RCP+ = 1.30 +/- 0.24(stat) +/- 0.12(syst). These measurements will improve the determination of the Cabibbo-Kobayashi-Maskawa angle gamma. They are performed here for the first time using data from hadron collisions.
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