1,443 research outputs found

    Electroweak Results from Hadron Colliders

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    A review of recent electroweak results from hadron colliders is given. Properties of the W and Z gauge bosons using final states containing electrons and muons based on large integrated luminosities are presented. The emphasis is placed on the measurement of the mass of the W boson and the measurement of trilinear gauge boson couplings

    Precision Electroweak Physics at Future Collider Experiments

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    We present an overview of the present status and prospects for progress in electroweak measurements at future collider experiments leading to precision tests of the Standard Model of Electroweak Interactions. Special attention is paid to the measurement of the W mass, the effective weak mixing angle, and the determination of the top quark mass. Their constraints on the Higgs boson mass are discussed.Comment: 17 pages, LaTeX2e, uses snow2e.cls, snowtimes.sty, 20 embedded figures, complete postscript file can be obtained from http://www.physics.buffalo.edu/~baur/ewk_snow.p

    Electrical Properties of Carbon Fiber Support Systems

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    Carbon fiber support structures have become common elements of detector designs for high energy physics experiments. Carbon fiber has many mechanical advantages but it is also characterized by high conductivity, particularly at high frequency, with associated design issues. This paper discusses the elements required for sound electrical performance of silicon detectors employing carbon fiber support elements. Tests on carbon fiber structures are presented indicating that carbon fiber must be regarded as a conductor for the frequency region of 10 to 100 MHz. The general principles of grounding configurations involving carbon fiber structures will be discussed. To illustrate the design requirements, measurements performed with a silicon detector on a carbon fiber support structure at small radius are presented. A grounding scheme employing copper-kapton mesh circuits is described and shown to provide adequate and robust detector performance.Comment: 20 pages, 11 figures, submitted to NI

    Architecture of a Silicon Strip Beam Position Monitor

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    A collaboration between Fermilab and the Institute for High Energy Physics (IHEP), Beijing, has developed a beam position monitor for the IHEP test beam facility. This telescope is based on 5 stations of silicon strip detectors having a pitch of 60 microns. The total active area of each layer of the detector is about 12x10 cm2. Readout of the strips is provided through the use of VA1` ASICs mounted on custom hybrid printed circuit boards and interfaced to Adapter Cards via copper-over-kapton flexible circuits. The Adapter Cards amplify and level-shift the signal for input to the Fermilab CAPTAN data acquisition nodes for data readout and channel configuration. These nodes deliver readout and temperature data from triggered events to an analysis computer over gigabit Ethernet links.Comment: Submitted to TWEPP 201

    Gluino Contribution to the 3-loop QCD beta function in the Minimal Supersymmetric Standard Model

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    We deduce the gluino contribution to the three-loop QCD \beta function within the minimal supersymmetric Standard Model (MSSM) from its standard QCD expression. The result is a first step in the computation of the full MSSM three-loop \beta function. In addition, in the case of a light gluino it provides the strong three-loop SUSY correction to the extrapolation of the strong coupling constant from the low energy regime to the Z region and up to the squark threshold.Comment: 11 pages, RevTex, 4 Postscript figur

    CLIC CDR - physics and detectors: CLIC conceptual design report.

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    This report forms part of the Conceptual Design Report (CDR) of the Compact LInear Collider (CLIC). The CLIC accelerator complex is described in a separate CDR volume. A third document, to appear later, will assess strategic scenarios for building and operating CLIC in successive center-of-mass energy stages. It is anticipated that CLIC will commence with operation at a few hundred GeV, giving access to precision standard-model physics like Higgs and top-quark physics. Then, depending on the physics landscape, CLIC operation would be staged in a few steps ultimately reaching the maximum 3 TeV center-of-mass energy. Such a scenario would maximize the physics potential of CLIC providing new physics discovery potential over a wide range of energies and the ability to make precision measurements of possible new states previously discovered at the Large Hadron Collider (LHC). The main purpose of this document is to address the physics potential of a future multi-TeV e{sup +}e{sup -} collider based on CLIC technology and to describe the essential features of a detector that are required to deliver the full physics potential of this machine. The experimental conditions at CLIC are significantly more challenging than those at previous electron-positron colliders due to the much higher levels of beam-induced backgrounds and the 0.5 ns bunch-spacing. Consequently, a large part of this report is devoted to understanding the impact of the machine environment on the detector with the aim of demonstrating, with the example of realistic detector concepts, that high precision physics measurements can be made at CLIC. Since the impact of background increases with energy, this document concentrates on the detector requirements and physics measurements at the highest CLIC center-of-mass energy of 3 TeV. One essential output of this report is the clear demonstration that a wide range of high precision physics measurements can be made at CLIC with detectors which are challenging, but considered feasible following a realistic future R&D program

    The Layer 0 Inner Silicon Detector of the D0 Experiment

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    This paper describes the design, fabrication, installation and performance of the new inner layer called Layer 0 (L0) that was inserted in the existing Run IIa Silicon Micro-Strip Tracker (SMT) of the D0 experiment at the Fermilab Tevatron collider. L0 provides tracking information from two layers of sensors, which are mounted with center lines at a radial distance of 16.1 mm and 17.6 mm respectively from the beam axis. The sensors and readout electronics are mounted on a specially designed and fabricated carbon fiber structure that includes cooling for sensor and readout electronics. The structure has a thin polyimide circuit bonded to it so that the circuit couples electrically to the carbon fiber allowing the support structure to be used both for detector grounding and a low impedance connection between the remotely mounted hybrids and the sensors.Comment: 28 pages, 9 figure

    Weakly-Coupled Higgs Bosons and Precision Electroweak Physics

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    We examine the prospects for discovering and elucidating the weakly-coupled Higgs sector at future collider experiments. The Higgs search consists of three phases: (i) discovery of a Higgs candidate, (ii) verification of the Higgs interpretation of the signal, and (iii) precision measurements of Higgs sector properties. The discovery of one Higgs boson with Standard Model properties is not sufficient to expose the underlying structure of the electroweak symmetry breaking dynamics. It is critical to search for evidence for a non-minimal Higgs sector and/or new physics associated with electroweak symmetry breaking dynamics. An improvement in precision electroweak data at future colliders can play a useful role in confirming the theoretical interpretation of the Higgs search results
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