637 research outputs found

    Precise Determination of the Neutron Magnetic Form Factor to Higher Q2Q^2

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    The neutron elastic magnetic form factor GMnG_M^n has been extracted from quasielastic scattering from deuterium in the CEBAF Large Acceptance Spectrometer, CLAS. The kinematic coverage of the measurement is continuous over a broad range, extending from below 1 GeV2GeV^2 to nearly 5 GeV2GeV^2 in four-momentum transfer squared. High precision is achieved by employing a ratio technique in which most uncertainties cancel, and by a simultaneous in-situ calibration of the neutron detection efficiency, the largest correction to the data. Preliminary results are shown with statistical errors only.Comment: Contribution to the proceedings of the Tenth International Conference on Baryons (2004), to be published in Nuclear Physics, Section

    Experimental Studies of Hadronization and Parton Propagation in the Space-Time Domain

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    Over the past decade, new data have become available from DESY, Jefferson Lab, Fermilab, and RHIC that connect to parton propagation and hadron formation. Semi-inclusive DIS on nuclei, the Drell-Yan reaction, and heavy-ion collisions all bring different kinds of information on parton propagation within a medium, while the most direct information on hadron formation comes from the DIS data. Over the next decade one can hope to begin to understand these data within a unified picture. We briefly survey the most relevant data and the common elements of the physics picture, then highlight the new Jefferson Lab data from CLAS, and close with prospects for the future.Comment: 8 pages, 6 figures - To appear in the conference proceedings for Quark Matter 2009, March 30 - April 4, Knoxville, Tennesse

    Kinematically Complete Measurements of p+p→p+n+(pi+) Near Threshold

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    This research was sponsored by the National Science Foundation Grant NSF PHY-931478

    Kinematically Complete Measurements of p+p → p+n+(pi+) Near Threshold

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    This research was sponsored by the National Science Foundation Grant NSF PHY-931478

    Report on CE-19: 16-O(p,n)16-F(0-) in the IUCF Cooler

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    This research was sponsored by the National Science Foundation Grant NSF PHY-931478

    An experimental study of the flow-induced noise created by a wall-mounted finite length airfoil

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    AIAA 2014-3290This paper presents the results of an experimental investigation of the sound produced by flow interaction with a wall-mounted finite length airfoil at low-to-moderate Reynolds number. Acoustic measurements have been taken in an anechoic wind tunnel at a range of Reynolds numbers, angles of attack and for a variety of airfoil aspect ratios (airfoil length to chord ratio) with a single microphone and two perpendicular planar microphone arrays. For comparison, measurements have also been taken with a semi-infinite or two- dimensional airfoil and a half-span airfoil with tip flow but no boundary layer impingement. The experimental data is used to examine changes in wall-mounted finite airfoil noise production as a function of Reynolds number, angle of attack and airfoil aspect ratio. Additionally, the data gives insight into the airfoil noise generation mechanisms and the influence of flow at the airfoil tip and wall junction on noise productionDanielle J. Moreau , Zebb Prime and Con J. Doola

    Analyzing Powers for pp → pnπ^+

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    This research was sponsored by the National Science Foundation Grant NSF PHY-931478

    Space-time evolution of hadronization

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    Beside its intrinsic interest for the insights it can give into color confinement, knowledge of the space-time evolution of hadronization is very important for correctly interpreting jet-quenching data in heavy ion collisions and extracting the properties of the produced medium. On the experimental side, the cleanest environment to study the space-time evolution of hadronization is semi-inclusive Deeply Inelastic Scattering on nuclear targets. On the theoretical side, 2 frameworks are presently competing to explain the observed attenuation of hadron production: quark energy loss (with hadron formation outside the nucleus) and nuclear absorption (with hadronization starting inside the nucleus). I discuss recent observables and ideas which will help to distinguish these 2 mechanisms and to measure the time scales of the hadronization process.Comment: 6 pages, 4 figures. Based on talks given at "Hot Quarks 2006", Villasimius, Italy, May 15-20, 2006, and at the "XLIV internataional winter meeting on nuclear physics", Bormio, Italy, Jan 29 - Feb 5, 2006. To appear in Eur.Phys.J.

    Differential cross section and recoil polarization measurements for the gamma p to K+ Lambda reaction using CLAS at Jefferson Lab

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    We present measurements of the differential cross section and Lambda recoil polarization for the gamma p to K+ Lambda reaction made using the CLAS detector at Jefferson Lab. These measurements cover the center-of-mass energy range from 1.62 to 2.84 GeV and a wide range of center-of-mass K+ production angles. Independent analyses were performed using the K+ p pi- and K+ p (missing pi -) final-state topologies; results from these analyses were found to exhibit good agreement. These differential cross section measurements show excellent agreement with previous CLAS and LEPS results and offer increased precision and a 300 MeV increase in energy coverage. The recoil polarization data agree well with previous results and offer a large increase in precision and a 500 MeV extension in energy range. The increased center-of-mass energy range that these data represent will allow for independent study of non-resonant K+ Lambda photoproduction mechanisms at all production angles.Comment: 22 pages, 16 figure

    Tensor Correlations Measured in 3He(e,e'pp)n

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    We have measured the 3He(e,e'pp)n reaction at an incident energy of 4.7 GeV over a wide kinematic range. We identified spectator correlated pp and pn nucleon pairs using kinematic cuts and measured their relative and total momentum distributions. This is the first measurement of the ratio of pp to pn pairs as a function of pair total momentum, ptotp_{tot}. For pair relative momenta between 0.3 and 0.5 GeV/c, the ratio is very small at low ptotp_{tot} and rises to approximately 0.5 at large ptotp_{tot}. This shows the dominance of tensor over central correlations at this relative momentum.Comment: 4 pages, 4 figures, submitted to PR
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