6,313 research outputs found

    Precise Electroweak Measurements at the Z0 Pole

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    Over the last decade, precise LEP and SLC measurements of electroweak coupling parameters at the Z0 pole have lead to tests of the Standard Model to unprecedented precision. This report presents a comprehensive review of these studies, including a review of relevant Z0 pole physics issues, facilities, instrumentation, and the measurements made. Global fits for the Higgs Boson mass and Z0-b coupling parameters are also presented.Comment: LaTex, 17 pages, 9 Postscript figures, uses ws-p8-50x6-00a.cls and epsfig.sty. Submitted to the Proceedings of the 1999 Conference on Physics in Collision, Ann Arbor, Michigan, June 24-26, 199

    Multiple hadron production in e+e- annihilation induced by heavy primary quarks. New analysis

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    In this paper we present an analysis of the multiple hadron production induced by primary heavy quarks in e+e- annihilation with the account of most complete and corrected experimental data. In the framework of perturbative QCD, new theoretical bounds on the asymptotically constant differences of the multiplicities in processes with light and heavy quarks are given.Comment: 26 pages, 7 figures, to be published in Particles & Nucle

    Geomorphology of the middle Mississippi River

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    DBS-SAS-MAS 9.Includes bibliographical references (pages 79-80).Prepared for U.S. Army Engineer Waterways Experiment Station, Corps of Engineers, Vicksburg, Mississippi under Contract No. DACW39-73-C- 0026 by Engineering Research Center, Colorado State University, Fort Collins, Colorado.January 1974.Sponsored by U.S. Army Engineer District, St. Louis

    Dual-species quantum degeneracy of potassium-40 and rubidium-87 on an atom chip

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    In this article we review our recent experiments with a 40K-87Rb mixture. We demonstrate rapid sympathetic cooling of a 40K-87Rb mixture to dual quantum degeneracy on an atom chip. We also provide details on efficient BEC production, species-selective magnetic confinement, and progress toward integration of an optical lattice with an atom chip. The efficiency of our evaporation allows us to reach dual degeneracy after just 6 s of evaporation - more rapidly than in conventional magnetic traps. When optimizing evaporative cooling for efficient evaporation of 87Rb alone we achieve BEC after just 4 s of evaporation and an 8 s total cycle time.Comment: 8 pages, 4 figures. To be published in the Proceedings of the 20th International Conference on Atomic Physics, 2006 (Innsbruck, Austria

    Effect of Magnetization Inhomogeneity on Magnetic Microtraps for Atoms

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    We report on the origin of fragmentation of ultracold atoms observed on a permanent magnetic film atom chip. A novel technique is used to characterize small spatial variations of the magnetic field near the film surface using radio frequency spectroscopy of the trapped atoms. Direct observations indicate the fragmentation is due to a corrugation of the magnetic potential caused by long range inhomogeneity in the film magnetization. A model which takes into account two-dimensional variations of the film magnetization is consistent with the observations.Comment: 4 pages, 4 figure

    Modeling meander morphodynamics over self-formed heterogeneous floodplains

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    This work addresses the signatures embedded in the planform geometry of meandering rivers consequent to the formation of floodplain heterogeneities as the river bends migrate. Two geomorphic features are specifically considered: scroll bars produced by lateral accretion of point bars at convex banks and oxbow lake fills consequent to neck cutoffs. The sedimentary architecture of these geomorphic units depends on the type and amount of sediment, and controls bank erodibility as the river impinges on them, favoring or contrasting the river migration. The geometry of numerically generated planforms obtained for different scenarios of floodplain heterogeneity is compared to that of natural meandering paths. Half meander metrics and spatial distribution of channel curvatures are used to disclose the complexity embedded in meandering geometry. Fourier Analysis, Principal Component Analysis, Singular Spectrum Analysis and Multivariate Singular Spectrum Analysis are used to emphasize the subtle but crucial differences which may emerge between apparently similar configurations. A closer similarity between observed and simulated planforms is attained when fully coupling flow and sediment dynamics (fully-coupled models) and when considering self-formed heterogeneities that are less erodible than the surrounding floodplain

    River environment: a reference document, The

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    DBS-PFL-YHC-SAS-14.Includes bibliographical references (pages A-1-A-26).Prepared for United States of the Interior Fish and Wildlife Service.December 1975

    High ET_T jets and double scattering

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    The recently found excess of high ET_T jets over current QCD predictions is attributed to gluon radiation at double scattering process inside a nucleon. The order of magnitude estimate of the cross section fits experimental findings rather well. The specific features of the process are discussed. Various similar hadronic effects related to the short radiation length are described.Comment: 6 pages, plain LaTe

    Interactions of Heavy Hadrons using Regge Phenomenology and the Quark Gluon String Model

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    The search for stable heavy exotic hadrons is a promising way to observe new physics processes at collider experiments. The discovery potential for such particles can be enhanced or suppressed by their interactions with detector material. This paper describes a model for the interactions in matter of stable hadrons containing an exotic quark of charges ±1/3e\pm {1/3}e or ±2/3e\pm {2/3}e using Regge phenomenology and the Quark Gluon String Model. The influence of such interactions on searches at the LHC is also discussed
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