58 research outputs found

    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

    CDF Run-II silicon detector: operations and aging

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    The CDF Run-II silicon microstrip detector has seen almost 12 fb −1 of proton-antiproton collisions over the last 10 years. It has shown remarkable performance, with 80% of its channels still operating error-free, and only one of its eight layers approaching the operational limits for full depletion. The measured depletion voltage and signal-to-noise ratio of these sensors give unique information about the behavior of sensors irradiated slowly over a long period of time. Data from heavily irradiated, double-sided sensors excludes a monotonic electric field inside the sensor and is instead consistent with a doubly-peaked field that is lower in the center of the sensor and higher at the edges

    Measurement of the resonance parameters of the X1(1(3)P(1)) and X2(1(3)P(2)) states of charmonium formed in antiproton-proton annihilations

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    We have studied the P-3(J) (chi(C)) states of charmonium in formation by antiproton-proton annihilations in experiment E835 at the Fermilab Antiproton Source. We report new measurements of the mass, width, and B(chi(cJ) -> (p) over barp)Gamma(chi(cJ) -> J/psi + anything) for the chi(c1) and chi(c2) by means of the inclusive reaction (p) over barp -> X-cJ -> J/psi + anything -> (e(+)e(-)) + anything. Using the sub-sample of events where chi(cJ) -> gamma + J/psi -> y + (e(+)e(-)) is fully reconstructed, we derive B(chi(cJ) -> (p) over barp)Gamma(chi(cJ) -> J/psi + gamma). We summarize the results of the E760 (updated) and E835 measurements of mass, width and B(chi(cJ) -> (p) over barp)Gamma(chi(cJ) -> J/psi + gamma) (J = 0, 1, 2) and discuss the significance of these measurements

    Measurement of azimuthal asymmetries associated with deeply virtual Compton scattering on an unpolarized deuterium target

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    Azimuthal asymmetries in exclusive electroproduction of a real photon from an unpolarized deuterium target are measured with respect to beam helicity and charge. They appear in the distribution of these photons in the azimuthal angle φ{symbol} around the virtual-photon direction, relative to the lepton scattering plane. The extracted asymmetries are attributed to either the deeply virtual Compton scattering process or its interference with the Bethe-Heitler process. They are compared with earlier results on the proton target. In the measured kinematic region, the beam-charge asymmetry amplitudes and the leading amplitudes of the beam-helicity asymmetries on an unpolarized deuteron target are compatible with the results from unpolarized protons. © 2009 Elsevier B.V. All rights reserved

    Measurement of the tensor structure function b(1) of the deuteron

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    The Hermes experiment has investigated the tensor spin structure of the deuteron using the 27.6 GeV/c positron beam of DESY HERA. The use of a tensor-polarized deuteron gas target with only a negligible residual vector polarization enabled the first measurement of the tensor asymmetry A(zz)(d) and the tensor structure function b(1)(d) for average values of the Bjorken variable 0.01 < 5 GeV2. The quantities A(zz)(d) and b(1)(d) are found to be nonzero. The rise of b(1)(d) for decreasing values of x can be interpreted to originate from the same mechanism that leads to nuclear shadowing in unpolarized scattering
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