45,554 research outputs found

    Properties of the top quark

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    Recent measurements of top-quark properties at the LHC and the Tevatron are presented. Most recent measurements of the top quark mass have been carried out by CMS using 19.7/19.7/fb of s=8\sqrt{s} = 8 TeV data including the study of the dependence on event kinematics. ATLAS uses the full Run I data at s=7\sqrt{s} = 7 TeV for a "3D" measurement that significantly reduces systematic uncertainties. D0 employs the full Run II data using the matrix element method to measure the top quark mass with significantly reduced systematic uncertainties. Many different measurements of the top quark exist to date and the most precise ones per decay channel per experiment have been combined into the first world combination with a relative precision of 0.44%. Latest updates of measurements of production asymmetries include the measurement of the \ttbar production asymmetry by D0 employing the full Run II data set, by CMS and ATLAS (including the polarization of the top quark) employing both the full data set at s=7\sqrt{s} = 7 TeV. CMS uses the full s=8\sqrt{s} = 8 TeV data to measure the top quark polarization in single top production, the ratio R{\cal R} of the branching fractions B(tWb)/B(tWq){\cal B}(t \rightarrow Wb) / {\cal B}(t \rightarrow Wq) and to search for flavor changing neutral currents. The results from all these measurements agree well with their respective Standard Model expectation.Comment: Large Hadron Collider Physics (LHCP) conference held at Columbia University in New York City from June 2-7, 201

    Top differential cross section measurements (Tevatron)

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    Differential cross sections in the top quark sector measured at the Fermilab Tevatron collider are presented. CDF used 2.7 fb1^{-1} of data and measured the differential cross section as a function of the invariant mass of the ttˉt\bar{t} system. The measurement shows good agreement with the standard model and furthermore is used to derive limits on the ratio κ/MPl\kappa /M_{Pl} for gravitons which decay to top quarks in the Randall-Sundrum model. D0 used 1.0 fb$^{-1} of data to measure the differential cross section as a function of the transverse momentum of the top quark. The measurement shows a good agreement to the higher order perturbative QCD prediction and various predictions based on various Monte-Carlo generators.Comment: To appear in the Proceedings of TOP2011, 4th International Workshop on Top Quark Physics, Spai

    Space shuttle: Basic subsonic static aerodynamic characteristics for Grumman H-33 orbiter configuration (M equals 0.17)

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    Results of an experimental aerodynamic investigation of the H-33 space orbiter are presented. The investigation was undertaken to determine static aerodynamic characteristics of the orbiter at a Mach number of 0.17. These data were determined by employing a 1/25 scale model of the orbiter for pitch and yaw variations of -4 degrees to 24 degrees to 15 degrees, respectively. Investigations were conducted in the 7 - by - 10 foot wind tunnel

    DEMAND FOR MEAT AND FISH PRODUCTS IN KOREA

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    The Korean livestock industry is currently facing the critical challenge of the market liberalization trend under the World Trade Organization. This study analyzes the consumption behavior of meat and fish products in Korea, by estimating the Linear Approximate Almost Ideal Demand System (LA/AIDS). The empirical results indicate that beef imports in Korea would increase in the future under trade liberalization. If cheap and better quality imported beef are introduced to Korean consumers, Hanwoo (Korean domestic cattle) beef would not maintain its market share. Key words: Meat, fish, trade liberalization, per capita consumption, demand, separability, and price elasticity.Meat, fish, trade liberalization, per capita consumption, demand, separability, and price elasticity., Demand and Price Analysis,
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