23,702 research outputs found

    Tables for correcting airfoil data obtained in the Langley 0.3-meter transonic cryogenic tunnel for sidewall boundary-layer effects

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    Tables for correcting airfoil data taken in the Langley 0.3-meter Transonic Cryogenic Tunnel for the presence of sidewall boundary layer are presented. The corrected Mach number and the correction factor are minutely altered by a 20 percent change in the boundary layer virtual origin distance. The sidewall boundary layer displacement thicknesses measured for perforated sidewall inserts and without boundary layer removal agree with the values calculated for solid sidewalls

    BARYON-BARYON INTERACTIONS IN LARGE N_C CHIRAL PERTURBATION THEORY

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    Interactions of two baryons are considered in large NCN_C chiral perturbation theory and compared to the interactions derived from the Skyrme model. Special attention is given to a torus-like configuration known to be present in the Skyrme model.Comment: 18 pages, REVTEX, 8 uuencoded PS figures appende

    Enskog Theory for Polydisperse Granular Mixtures II. Sonine Polynomial Approximation

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    The linear integral equations defining the Navier-Stokes (NS) transport coefficients for polydisperse granular mixtures of smooth inelastic hard disks or spheres are solved by using the leading terms in a Sonine polynomial expansion. Explicit expressions for all the NS transport coefficients are given in terms of the sizes, masses, compositions, density and restitution coefficients. In addition, the cooling rate is also evaluated to first order in the gradients. The results hold for arbitrary degree of inelasticity and are not limited to specific values of the parameters of the mixture. Finally, a detailed comparison between the derivation of the current theory and previous theories for mixtures is made, with attention paid to the implication of the various treatments employed to date.Comment: 26 pages, to be published in Phys. Rev.

    Controlled manipulation of light by cooperative response of atoms in an optical lattice

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    We show that a cooperative atom response in an optical lattice to resonant incident light can be employed for precise control and manipulation of light on a subwavelength scale. Specific collective excitation modes of the system that result from strong light-mediated dipole-dipole interactions can be addressed by tailoring the spatial phase-profile of the incident light. We demonstrate how the collective response can be used to produce optical excitations at well-isolated sites on the lattice.Comment: 8 pages, 1 figur

    Contact values of the radial distribution functions of additive hard-sphere mixtures in d dimensions: A new proposal

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    The contact values gij(σij)g_{ij}(\sigma_{ij}) of the radial distribution functions of a dd-dimensional mixture of (additive) hard spheres are considered. A `universality' assumption is put forward, according to which gij(σij)=G(η,zij)g_{ij}(\sigma_{ij})=G(\eta, z_{ij}), where GG is a common function for all the mixtures of the same dimensionality, regardless of the number of components, η\eta is the packing fraction of the mixture, and zijz_{ij} is a dimensionless parameter that depends on the size distribution and the diameters of spheres ii and jj. For d=3d=3, this universality assumption holds for the contact values of the Percus--Yevick approximation, the Scaled Particle Theory, and, consequently, the Boublik--Grundke--Henderson--Lee--Levesque approximation. Known exact consistency conditions are used to express G(η,0)G(\eta,0), G(η,1)G(\eta,1), and G(η,2)G(\eta,2) in terms of the radial distribution at contact of the one-component system. Two specific proposals consistent with the above conditions (a quadratic form and a rational form) are made for the zz-dependence of G(η,z)G(\eta,z). For one-dimensional systems, the proposals for the contact values reduce to the exact result. Good agreement between the predictions of the proposals and available numerical results is found for d=2d=2, 3, 4, and 5.Comment: 10 pages, 11 figures; Figure 1 changed; Figure 5 is new; New references added; accepted for publication in J. Chem. Phy

    Strong Λπ\Lambda \pi Phase Shifts for CP Violation in Weak Ξ→Λπ\Xi \rightarrow \Lambda \pi Decay

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    Strong interaction Λπ\Lambda\pi phase shifts relevant for the weak nonleptonic decay Ξ→Λπ\Xi \rightarrow \Lambda \pi are calculated using baryon chiral perturbation theory. We find in leading order that the S-wave phase shift vanishes and the J=12J={1 \over 2} P-wave phase shift is −1.7o-1.7 ^{\rm o} . The small phase shifts imply that CP violation in this decay will be difficult to observe. Our results follow from chiral SU(2)L×SU(2)RSU(2)_L\times SU(2)_R symmetry.Comment: 8 pages, uses phyzzx, 2 figures included as uuencoded file, CALT-68-1940 and CMU-HEP94-2

    Hilbert Series for Flavor Invariants of the Standard Model

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    The Hilbert series is computed for the lepton flavor invariants of the Standard Model with three generations including the right-handed neutrino sector needed to generate light neutrino masses via the see-saw mechanism. We also compute the Hilbert series of the quark flavor invariants for the case of four generations.Comment: 6 page

    Baryon Octet magnetic moments in χ\chiPT: More on the importance of the Decuplet

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    We address the impact of treating the decuplet of spin-3/2 baryons as an explicit degree of freedom in the chiral expansion of the magnetic moments of the octet of spin-1/2 baryons. We carry out a complete calculation of the octet moments to O(1/\lamchic), including decuplet contributions to the chiral loops. In contrast to results of previous analyses, we find that inclusion of the decuplet preserves the convergence behavior of the chiral expansion implied by power counting arguments.Comment: 17 pages, 2 figures. Includes axodraw.sty needed for figures Minor typos correcte
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