6,460 research outputs found

    Experimental Techniques

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    Experimental application of sum rules for electron energy loss magnetic chiral dichroism

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    We present a derivation of the orbital and spin sum rules for magnetic circular dichroic spectra measured by electron energy loss spectroscopy in a transmission electron microscope. These sum rules are obtained from the differential cross section calculated for symmetric positions in the diffraction pattern. Orbital and spin magnetic moments are expressed explicitly in terms of experimental spectra and dynamical diffraction coefficients. We estimate the ratio of spin to orbital magnetic moments and discuss first experimental results for the Fe L_{2,3} edge.Comment: 11 pages, 2 figure

    Energy Linearity and Resolution of the ATLAS Electromagnetic Barrel Calorimeter in an Electron Test-Beam

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    A module of the ATLAS electromagnetic barrel liquid argon calorimeter was exposed to the CERN electron test-beam at the H8 beam line upgraded for precision momentum measurement. The available energies of the electron beam ranged from 10 to 245 GeV. The electron beam impinged at one point corresponding to a pseudo-rapidity of eta=0.687 and an azimuthal angle of phi=0.28 in the ATLAS coordinate system. A detailed study of several effects biasing the electron energy measurement allowed an energy reconstruction procedure to be developed that ensures a good linearity and a good resolution. Use is made of detailed Monte Carlo simulations based on Geant which describe the longitudinal and transverse shower profiles as well as the energy distributions. For electron energies between 15 GeV and 180 GeV the deviation of the measured incident electron energy over the beam energy is within 0.1%. The systematic uncertainty of the measurement is about 0.1% at low energies and negligible at high energies. The energy resolution is found to be about 10% sqrt(E) for the sampling term and about 0.2% for the local constant term

    The Minimal Supersymmetric Standard Model: Group Summary Report

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    CONTENTS: 1. Synopsis, 2. The MSSM Spectrum, 3. The Physical Parameters, 4. Higgs Boson Production and Decays, 5. SUSY Particle Production and Decays, 6. Experimental Bounds on SUSY Particle Masses, 7. References.Comment: 121 pages, latex + epsfig, graphicx, axodraw, Report of the MSSM working group for the Workshop "GDR-Supersym\'etrie",France. Rep. PM/98-4

    Scales of Whiteness and Racial Mixing: Challenging and Confirming Racial Categories

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    This paper examines personal and public portrayals of the self and family articulated by heterosexual mixed-race households living in the Pacific Northwest of the United States. It argues that an attention to scale sheds light on how mixed-race partnerships and households both reproduce a racial hierarchy and express shifting racial identities. A focus on the work of whiteness – defined here as an evaluative set of practices and processes that implicitly or explicitly legitimate a static racial hierarchy – in the confirmation of and challenges to racial categories further specifies my claims. I explore seemingly contradictory expressions of race in an effort to 1) point to the resilience of racism and to 2) indicate moments and spaces wherein racial identities change. Through qualitative interviews and a scalar lens, I aim to contribute to conversations on where and how stalwart assumptions about race emerge and add to considerations of where and how interpretations of race adopt a more contextual and dynamic form. Recognizing both the instances when different racialized landscapes come to the fore and the times when ardent stereotypes surface can help pave the way for re-imagining racial futures

    Offender rehabilitation : a normative framework for forensic psychologists

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    Community protection from offenders is addressed through punishment, deterrence, incapacitation, and/or rehabilitation. The current public policy debate about community protection refers to community rights as opposed to offender rights as if the two are mutually exclusive. However, in this article it will be argued that offender rehabilitation can enhance community protection if it addresses community rights and offender rights. The author proposes a normative framework to guide forensic psychologists in offender rehabilitation. The normative framework considers psychological theory&mdash;the risk-need model to address community rights and the good lives model to address offender rights. However, forensic psychologists operate within the context of the criminal justice system and so legal theory will also be considered. Therapeutic jurisprudence can balance community rights and offender rights within a human rights perspective. The proposed normative framework guides forensic psychologists in the assessment of risk, the treatment of need, and the management of readiness in balancing community rights and offender rights. Within a human rights perspective, forensic psychologists have a duty to provide offenders with the opportunity to make autonomous decisions about whether to accept or reject rehabilitation. <br /

    Measurement of Neutrino-Electron Scattering Cross-Section with a CsI(Tl) Scintillating Crystal Array at the Kuo-Sheng Nuclear Power Reactor

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    The νˉee\bar{\nu}_{e}-e^{-} elastic scattering cross-section was measured with a CsI(Tl) scintillating crystal array having a total mass of 187kg. The detector was exposed to an average reactor νˉe\bar{\nu}_{e} flux of 6.4×1012 cm2s1\rm{6.4\times 10^{12} ~ cm^{-2}s^{-1}} at the Kuo-Sheng Nuclear Power Station. The experimental design, conceptual merits, detector hardware, data analysis and background understanding of the experiment are presented. Using 29882/7369 kg-days of Reactor ON/OFF data, the Standard Model(SM) electroweak interaction was probed at the squared 4-momentum transfer range of Q23×106 GeV2\rm{Q^2 \sim 3 \times 10^{-6} ~ GeV^2}. The ratio of experimental to SM cross-sections of ξ=[1.08±0.21(stat)±0.16(sys)] \xi =[ 1.08 \pm 0.21(stat)\pm 0.16(sys)] was measured. Constraints on the electroweak parameters (gV,gA)(g_V , g_A) were placed, corresponding to a weak mixing angle measurement of \s2tw = 0.251 \pm 0.031({\it stat}) \pm 0.024({\it sys}) . Destructive interference in the SM \nuebar -e process was verified. Bounds on anomalous neutrino electromagnetic properties were placed: neutrino magnetic moment at \mu_{\nuebar}< 2.2 \times 10^{-10} \mu_{\rm B} and the neutrino charge radius at -2.1 \times 10^{-32} ~{\rm cm^{2}} < \nuchrad < 3.3 \times 10^{-32} ~{\rm cm^{2}}, both at 90% confidence level.Comment: 18 Figures, 7 Tables; published version as V2 with minor revision from V

    Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

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    This paper presents measurements of the W+μ+νW^+ \rightarrow \mu^+\nu and WμνW^- \rightarrow \mu^-\nu cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13

    Search for squarks and gluinos with the ATLAS detector in final states with jets and missing transverse momentum using √s=8 TeV proton-proton collision data

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    A search for squarks and gluinos in final states containing high-p T jets, missing transverse momentum and no electrons or muons is presented. The data were recorded in 2012 by the ATLAS experiment in s√=8 TeV proton-proton collisions at the Large Hadron Collider, with a total integrated luminosity of 20.3 fb−1. Results are interpreted in a variety of simplified and specific supersymmetry-breaking models assuming that R-parity is conserved and that the lightest neutralino is the lightest supersymmetric particle. An exclusion limit at the 95% confidence level on the mass of the gluino is set at 1330 GeV for a simplified model incorporating only a gluino and the lightest neutralino. For a simplified model involving the strong production of first- and second-generation squarks, squark masses below 850 GeV (440 GeV) are excluded for a massless lightest neutralino, assuming mass degenerate (single light-flavour) squarks. In mSUGRA/CMSSM models with tan β = 30, A 0 = −2m 0 and μ > 0, squarks and gluinos of equal mass are excluded for masses below 1700 GeV. Additional limits are set for non-universal Higgs mass models with gaugino mediation and for simplified models involving the pair production of gluinos, each decaying to a top squark and a top quark, with the top squark decaying to a charm quark and a neutralino. These limits extend the region of supersymmetric parameter space excluded by previous searches with the ATLAS detector
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