6,295 research outputs found

    Evaluation of ADAM/1 model for advanced coal extraction concepts

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    Several existing computer programs for estimating life cycle cost of mining systems were evaluated. A commercially available program, ADAM/1 was found to be satisfactory in relation to the needs of the advanced coal extraction project. Two test cases were run to confirm the ability of the program to handle nonconventional mining equipment and procedures. The results were satisfactory. The model, therefore, is recommended to the project team for evaluation of their conceptual designs

    Characteristic impedance of microstrip lines

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    The dyadic Green's function for a current embedded in a grounded dielectric slab is used to analyze microstrip lines at millimeter wave frequencies. The dyadic Green's function accounts accurately for fringing fields and dielectric cover over the microstrip line. Using Rumsey's reaction concept, an expression for the characteristic impedance is obtained. The numerical results are compared with other reported results

    A method for determining CP violating phase γ\gamma

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    A new way of determining the phases of weak amplitudes in charged BB decays based on SU(3) symmetry is proposed. The CP violating phase γ\gamma can now be determined without the previous difficulty associated with electroweak penguins.Comment: 9 pages plus one figure, Revte

    Electroweak Model Independent Tests for SU(3) Symmetry in Hadronic B Decays

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    We study effects of new physics beyond the Standard Model on SU(3) symmetry in charmless hadronic two body B decays. It is found that several equalities for some of the decay amplitudes, such as A(Bd(Bu)π+π,π+K(πKˉ0))=A(BsK+π,KK+(K0Kˉ0))A(B_d (B_u) \to \pi^+\pi^-,\pi^+ K^- (\pi^- \bar K^0)) =A(B_s \to K^+ \pi^-, K^- K^+ (K^0 \bar K^0)), A(Bdπ+ρ,πρ+,Kρ+,π+K)=A(BsK+ρ,πK+,KK+,K+K)A(B_d \to \pi^+\rho^-, \pi^- \rho^+, K^-\rho^+, \pi^+ K^{*-}) = A(B_s \to K^+ \rho^-, \pi^- K^{*+}, K^- K^{*+}, K^+ K^{*-}), A(Bd(Bu)ρ+ρ,ρ+K(ρKˉ0))=A(BsK+ρ,KK+(K0Kˉ0))A(B_d (B_u) \to \rho^+\rho^-, \rho^+ K^{*-}(\rho^- \bar K^{*0})) =A(B_s \to K^{*+} \rho^-, K^{*-} K^{*+} (K^{*0} \bar K^{*0})), predicted by SU(3) symmetry in the SM are not affected by new physics. These relations provide important electroweak model independent tests for SU(3) symmetry in B decays.Comment: 4 pages, revte

    Analysis of Discontinuities in a Rectangular Waveguide Using Dyadic Green's Function Approach in Conjunction with Method of Moments

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    The dyadic Green's function for an electric current source placed in a rectangular waveguide is derived using a magnetic vector potential approach. A complete solution for the electric and magnetic fields including the source location is obtained by simple differentiation of the vector potential around the source location. The simple differentiation approach which gives electric and magnetic fields identical to an earlier derivation is overlooked by the earlier workers in the derivation of the dyadic Green's function particularly around the source location. Numerical results obtained using the Green's function approach are compared with the results obtained using the Finite Element Method (FEM)

    Application of Finite Element Method to Analyze Inflatable Waveguide Structures

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    A Finite Element Method (FEM) is presented to determine propagation characteristics of deformed inflatable rectangular waveguide. Various deformations that might be present in an inflatable waveguide are analyzed using the FEM. The FEM procedure and the code developed here are so general that they can be used for any other deformations that are not considered in this report. The code is validated by applying the present code to rectangular waveguide without any deformations and comparing the numerical results with earlier published results

    Spin Effects in the Local Density of States of GaAs

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    We present spin-resolved measurements of the local density of states in Si doped GaAs. Both spin components exhibit strong mesoscopic fluctuations. In the magnetic quantum limit, the main features of the spin-up and spin-down components of the local density of states are found to be identical apart from Zeeman splitting. Based on this observation, we introduce a mesoscopic method to measure the gg-factor in a material where macroscopic methods are severely restricted by disorder. Differences between the spin-up and spin-down components are discussed in terms of spin relaxation due to spin-orbit coupling.Comment: 4 pages and 5 figure

    Bˉ0π+X\bar B^0 \to \pi^+ X in the Standard Model

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    In this paper we investigate the possibility of studying BπB\to \pi form factor using the semi-inclusive decays Bˉ0π++Xq\bar B^0 \to \pi^+ + X_q. In general BPXB\to PX semi-inclusive decays involve several hadronic parameters. But for Bˉ0π+Xq\bar B^0 \to \pi^+ X_q decays we find that in the factorization approximation, the only unknown hadronic parameters are the form factors F0,1BπF^{B\to \pi}_{0,1}. Therefore these form factors can be studied in Bˉ0π+Xq\bar B^0 \to \pi^+ X_q decays. Using theoretical model calculations for the form factors the branching ratios for Bˉ0π+Xd(ΔS=0)\bar B^0 \to \pi^+ X_d(\Delta S = 0) and Bˉ0π+Xs(ΔS=1)\bar B^0 \to \pi^+ X_s (\Delta S = -1), with the cut Eπ>2.1E_{\pi} > 2.1 GeV, are estimated to be in the ranges of (3.14.9)×105(F1Bπ(0)/0.33)2(3.1\sim 4.9) \times 10^{-5}(F^{B\to \pi}_1(0)/0.33)^2 and (2.54.2)×105(F1Bπ(0)/0.33)2(2.5\sim 4.2)\times 10^{-5}(F_1^{B\to \pi}(0)/0.33)^2, respectively, depending on the value of γ\gamma. The combined branching ratio for Bˉ0π+(Xd+Xs)\bar B^0 \to \pi^+ (X_d+ X_s) is about 7.4×105(F1Bπ(0)/0.33)27.4\times 10^{-5} (F^{B\to \pi}_1(0)/0.33)^2 and is insensitive to γ\gamma. We also discuss CP asymmetries in these decay modes.Comment: RevTex 8 pages and two figure

    Constraints on the phase γ\gamma and new physics from BKπB\to K\pi Decays

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    Recent results from CLEO on BKπB\to K\pi indicate that the phase γ\gamma may be substantially different from that obtained from other fit to the KM matrix elements in the Standard Model. We show that γ\gamma extracted using BKπ,ππB\to K\pi, \pi\pi is sensitive to new physics occurring at loop level. It provides a powerful method to probe new physics in electroweak penguin interactions. Using effects due to anomalous gauge couplings as an example, we show that within the allowed ranges for these couplings information about γ\gamma obtained from BKπ,ππB\to K \pi, \pi\pi can be very different from the Standard Model prediction.Comment: Revised version with analysis done using new data from CLEO. RevTex, 11 Pages with two figure
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