25,896 research outputs found

    Kaluza-Klein Gluons as a Diagnostic of Warped Models

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    We study the properties of g1g^{1}, the first excited state of the gluon in representative variants of the Randall Sundrum model with the Standard Model fields in the bulk. We find that measurements of the coupling to light quarks (from the inclusive cross-section for pp→g1→ttˉpp\to g^{1} \to t\bar t), the coupling to bottom quarks (from the rate of pp→g1bpp\to g^{1} b), as well as the overall width, can provide powerful discriminants between the models. In models with large brane kinetic terms, the g1g^1 resonance can even potentially be discovered decaying into dijets against the large QCD background. We also derive bounds based on existing Tevatron searches for resonant ttˉt \bar{t} production and find that they require Mg1≳950M_{g^{1}} \gtrsim 950 GeV. In addition we explore the pattern of interference between the g1g^1 signal and the non-resonant SM background, defining an asymmetry parameter for the invariant mass distribution. The interference probes the relative signs of the couplings of the g1g^{1} to light quark pairs and to ttˉt\bar t, and thus provides an indication that the top is localized on the other side of the extra dimension from the light quarks, as is typical in the RS framework.Comment: 25 pages, 10 figure

    Entanglement Spectra of the quantum hard-square model: Holographic minimal models

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    We study the entanglement properties of a quantum lattice-gas model for which we can find the exact ground state (of the Rokhsar-Kivelson type). The ground state can be expressed as a superposition of states, each of which is characterized by a particle configuration with nearest-neighbor exclusion. We show that the reduced density matrix of the model on a ladder is intimately related to the transfer matrix of the classical hard-square model. The entanglement spectra of the model on square and triangular ladders are critical when parameters are chosen so that the corresponding classical hard-square models are critical. A detailed analysis reveals that the critical theories for the entanglement Hamiltonians are c<1c<1 minimal conformal field theories. We further show that the entanglement Hamiltonian for the triangular ladder is integrable despite the fact that the original quantum lattice-gas model is non-integrable.Comment: 10 pages, 8 figure

    The Nutrition Transition in High and Low-Income Countries: What are the Policy Lessons?

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    The world has seen a remarkable shift from a period when diets, activity patterns and body composition were characterized by the period termed the receding famine pattern to one dominated by nutrition-related non-communicable diseases (NR-NCDs). This presentation first examines the speed of these changes, summarizes dietary changes, and provides some sense of the way the burden of obesity is shifting from the rich to the poor not only in urban but also rural areas throughout the world. The focus is on the lower- and middle- income countries of Asia, Africa, the Middle East, and Latin America but some examples will come from the United States, Australia, and the UK. After showing that changes are occurring at great speed and at earlier stages of countries' economic and social development, the presentation shifts to some of the critical policy opportunities and some example of options. Few policy lessons exist at a macro level outside of selected countries such as South Korea and Finland. Examples of ways price policy and other options might work, using Chinese longitudinal case studies, are presented. The challenge is for the agricultural economics profession to focus on this major global issue-one which challenges some of the earlier paradigms of food policy an agricultural development.diet composition, price policy, economic growth, health effects, Food Consumption/Nutrition/Food Safety,

    Computer program documentation for a subcritical wing design code using higher order far-field drag minimization

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    A subsonic, linearized aerodynamic theory, wing design program for one or two planforms was developed which uses a vortex lattice near field model and a higher order panel method in the far field. The theoretical development of the wake model and its implementation in the vortex lattice design code are summarized and sample results are given. Detailed program usage instructions, sample input and output data, and a program listing are presented in the Appendixes. The far field wake model assumes a wake vortex sheet whose strength varies piecewise linearly in the spanwise direction. From this model analytical expressions for lift coefficient, induced drag coefficient, pitching moment coefficient, and bending moment coefficient were developed. From these relationships a direct optimization scheme is used to determine the optimum wake vorticity distribution for minimum induced drag, subject to constraints on lift, and pitching or bending moment. Integration spanwise yields the bound circulation, which is interpolated in the near field vortex lattice to obtain the design camber surface(s)
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