47 research outputs found

    Top Mass Measurements at the Tevatron Run II

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    The latest top quark mass measurements by the CDF and D\O~ experiments are presented here. The mass has been determined in the dilepton (\ttbar \to e\mu,ee,\mu\mu + jets +\met) and lepton plus jets (\ttbar \to e or μ\mu + jets +\met) final states. The most accurate single result from lepton plus jets channel is 173.53.6+3.7^{+3.7}_{-3.6}(stat. + Jet Energy Scale Systematic)±1.3\pm1.3(syst.) ~GeV/c2^{2}, which is better than the combined CDF and D\O~ Run~I average. A preliminary and unofficial average of the best experimental Run~II results gives MtopM_{top} = 172.7±3.5172.7\pm3.5 GeV/c2{^2}.Comment: 19 pages, 8 figures, presented at 19th Rencontres de Physique De La Vallee D'Aoste, La Thuil

    The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe

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    The preponderance of matter over antimatter in the early Universe, the dynamics of the supernova bursts that produced the heavy elements necessary for life and whether protons eventually decay --- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our Universe, its current state and its eventual fate. The Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed plan for a world-class experiment dedicated to addressing these questions. LBNE is conceived around three central components: (1) a new, high-intensity neutrino source generated from a megawatt-class proton accelerator at Fermi National Accelerator Laboratory, (2) a near neutrino detector just downstream of the source, and (3) a massive liquid argon time-projection chamber deployed as a far detector deep underground at the Sanford Underground Research Facility. This facility, located at the site of the former Homestake Mine in Lead, South Dakota, is approximately 1,300 km from the neutrino source at Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino charge-parity symmetry violation and mass ordering effects. This ambitious yet cost-effective design incorporates scalability and flexibility and can accommodate a variety of upgrades and contributions. With its exceptional combination of experimental configuration, technical capabilities, and potential for transformative discoveries, LBNE promises to be a vital facility for the field of particle physics worldwide, providing physicists from around the globe with opportunities to collaborate in a twenty to thirty year program of exciting science. In this document we provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess.Comment: Major update of previous version. This is the reference document for LBNE science program and current status. Chapters 1, 3, and 9 provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess. 288 pages, 116 figure

    STUDIES OF THE CHROMATICITY, TUNE, AND COUPLING DRIFT IN THE TEVATRON*

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    Abstract Chromaticity drift is a well-known and more or less well-understood phenomenon in superconducting colliders such as the Tevatron. Less known is the effect of tune and coupling drift, also observed in the Tevatron during injection. These effects are caused by field drifts in the superconducting magnets. Controlling the behavior of the tune, coupling, and chromaticity is an important part of reducing beam loss at injection and at the start of the Tevatron ramp. In this context we conducted several beam-studies during the period of April to August 2004 in which we measured the drift in the Tevatron chromaticity, tunes, and coupling during the injection porch. In some cases we also measured the snapback at the start of the ramp. We will present the results of these studies data and put them into context of the results of off-line magnetic measurements conducted in spare Tevatron dipoles

    Advances in the Understanding and Operations of Superconducting Colliders

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    Chromaticity drift is a well-known and more or less understood phenomenon in superconducting colliders such as the Tevatron. Less known is the effect of tune and coupling drift, also observed in the Tevatron during injection. Recently, in the context of the Tevatron collider run II, extensive studies of chromaticity, tune and coupling drifts were conducted to improve Tevatron performance. The studies included not only beam studies but also extensive off-line magnetic measurements on spare Tevatron dipoles. Some of these measurements were conducted in collaboration with Cern. Cern’s interest in multipole drifts is related to the future LHC, which will have similar issues. The following will report on the results of these studies. A new result, which will be presented here also, is related to fast drifts occurring in the first few seconds of the injection porch. These fast drifts were observed first in the Tevatron and efforts are underway to explain them. The author will also attempt to broaden the discussion to include the discussion of drift effects in the accelerating fields of superconducting linear accelerators
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