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CDF Collaboration(Aaltonen, T. et al), & Cabrera, S. (2012). Measurements of the Angular Distributions in the Decays B -> K-(*)mu(+)mu(-) at CDF. Phys. Rev. Lett., 108(8), 081807–8pp.
Abstract: We report an indirect search for nonstandard model physics using the flavor-changing neutral current decays B -> K-(*)mu(+)mu(-). We reconstruct the decays and measure their angular distributions, as a function of q(2) = M(mu mu)(2)c(2), where M-mu μis the dimuon mass, in p (P) over bar collisions at root s = 1.96 Tev using a data sample corresponding to an integrated luminosity of 6.8 fb(-1). The transverse polarization asymmetry A(T)((2)) and the time-reversal-odd charge-and-parity asymmetry A(im) are measured for the first time, together with the K* longitudinal polarization fraction F-L and the muon forward-backward asymmetry A(FB) for the decays B-0 -> K*(0)mu(+)mu(-) and B -> K*(+)mu(+)mu(-). The B -> K*mu(+)mu(-) forward-backward asymmetry in the most sensitive kinematic regime, 1 <= q(2) < 6 GeV2/c(2), is measured to be A(FB) 0.29(-0.23)(+0.20) (stat) +/- 0.07 (syst), the most precise result to date. No deviations from the standard model predictions are observed.
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CDF Collaboration(Aaltonen, T. et al), & Cabrera, S. (2011). Measurement of b Hadron Lifetimes in Exclusive Decays Containing a J/Psi in p(p)over-bar Collisions at sqrt(s)=1.96 TeV. Phys. Rev. Lett., 106(12), 121804–8pp.
Abstract: We report on a measurement of b-hadron lifetimes in the fully reconstructed decay modes B+-> J/psi K+, B-0 -> J/psi K*(892)(0), B-0 -> J/psi K-s(0), and Lambda(0)(b)-> J/psi Lambda(0) using data corresponding to an integrated luminosity of 4.3 fb(-1), collected by the CDF II detector at the Fermilab Tevatron. The measured lifetimes are tau(B+)=[1.639 +/- 0.009(stat)+/- 0.009(syst)]ps, tau(B-0)=[1.507 +/- 0.010(stat)+/- 0.008(syst)]ps, and tau(Lambda(0)(b))=[1.537 +/- 0.045(stat)+/- 0.014(syst)]ps. The lifetime ratios are tau(B+)/tau(B-0)=[1.088 +/- 0.009(stat)+/- 0.004(syst)] and tau(Lambda(0)(b))/tau(B-0)=[1.020 +/- 0.030(stat)+/- 0.008(syst)]. These are the most precise determinations of these quantities from a single experiment.
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CDF Collaboration(Aaltonen, T. et al), & Cabrera, S. (2011). Measurement of the Forward-Backward Asymmetry in the B -> K-(*) mu(+)mu(-) Decay and First Observation of the B-s(0) -> phi mu(+)mu(-) Decay. Phys. Rev. Lett., 106(16), 161801–7pp.
Abstract: We reconstruct the rare decays B+ -> K+ mu(+)mu(-), B-0 -> K*(892)(0) mu(+)mu(-), and B-s(0) -> phi(1020) mu(+)mu(-) in a data sample corresponding to 4.4 fb(-1) collected in p (p) over bar collisions at root s = 1.96 TeV by the CDF II detector at the Tevatron Collider. Using 121 +/- 16 B+ -> K+ mu(+)mu(-) and 101 +/- 12 B-0 -> K-*0 mu(+)mu(-) decays we report the branching ratios. In addition, we report the differential branching ratio and the muon forwardbackward asymmetry in the B+ and B-0 decay modes, and the K-*0 longitudinal polarization fraction in the B-0 decay mode with respect to the squared dimuon mass. These are consistent with the predictions, and most recent determinations from other experiments and of comparable accuracy. We also report the first observation of the B-s(0) -> phi mu(+)mu(-) decay and measure its branching ratio BR(B-s(0) -> phi mu(+)mu(-)) = [1.44 +/- 0.33 +/- 0.46] x 10(-6) using 27 +/- 6 signal events. This is currently the most rare B-s(0) decay observed.
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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). Observation of the Baryonic Flavor-Changing Neutral Current Decay Lambda(0)(b) -> Lambda mu(+)mu(-). Phys. Rev. Lett., 107(20), 201802–8pp.
Abstract: We report the first observation of the baryonic flavor-changing neutral current decay Lambda(0)(b) -> Lambda mu(+)mu(-) with 24 signal events and a statistical significance of 5.8 Gaussian standard deviations. This measurement uses a p (p) over bar collisions data sample corresponding to 6.8 fb(-1) at root s = 1.96 TeV collected by the CDF II detector at the Tevatron collider. The total and differential branching ratios for Lambda(0)(b) -> Lambda mu(+)mu(-) are measured. We find B(Lambda(0)(b) -> Lambda mu(+)mu(-)) = [1.73 +/- 0.42(stat) +/- (syst)] x 10(-6). We also report the first measurement of the differential branching ratio of B(s)(0) -> phi mu(+)mu(-), using 49 signal events. In addition, we report branching ratios for B(+) -> K(+)mu(+)mu(-), B(0) -> K(0)mu(+)mu(-), and B -> K*(892)mu(+)mu(-) decays.
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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. (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. (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). Exclusion of an Exotic Top Quark with-4/3 Electric Charge Using Soft Lepton Tagging. Phys. Rev. Lett., 105(10), 101801–7pp.
Abstract: We present a measurement of the electric charge of the top quark using p (p) over bar collisions corresponding to an integrated luminosity of 2: 7 fb(-1) at the CDF II detector. We reconstruct t (t) over bar events in the lepton + jets final state. We use soft lepton taggers to determine the flavor of the b jets, which we use to reconstruct the top quark's electric charge and exclude an exotic top quark with -4/3 charge at 95% confidence level. This is the strongest exclusion of the exotic charge scenario and the first to use soft leptons for this purpose.
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CDF Collaboration(Aaltonen, T. et al), & Cabrera, S. (2010). Search for the Production of Scalar Bottom Quarks in p(p)over-bar Collisions at root s=1.96 TeV. Phys. Rev. Lett., 105(8), 081802–7pp.
Abstract: We 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.
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