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Showing 1 to 20 of 31 for “"Spin asymmetry"”.
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Double Spin Asymmetry in d →(e→e'p)n
… the CLAS detector at Jefferson Lab, double spin asymmetries (A ∥) for quasi-elastic electron scattering off the deuteron have been measured at several beam energies. The data were collected during the EG1 experiment, which scattered longitudinally polarized electrons with energies from 1.6 …
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Beam spin asymmetry measurements in deeply virtual Compton scattering
<p>Beam Spin Asymmetry (BSA) is studied in the Deeply Virtual Compton Scattering (DVCS) using CLAS detector at Jefferson Lab and longitudinally polarized electron beam with 4.8 GeV energy. This asymmetry is directly proportional to the imaginary part of the scattering amplitude, which relates it to …
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Triple Coincidence Beam Spin Asymmetry Measurements in Deeply Virtual Compton Scattering
… Laboratory in Fall 2004. I present here Beam Spin Asymmetry (BSA) results for the <em>ep</em> → <em>epγ </em>reaction studied in the E00-110 experiment with fully exclusive triple coincidence <em>H</em>(<em>e</em>, <em>e'γp </em>) detection. I present a re-calibration of the electromagnetic …
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Precision measurement of neutron spin asymmetry An1 at large xBj using CEBAF at 5.7 GeV
Nucleon spin structure has remained one of the key issues of hadronic physics since the 1980's. Among the unsolved questions, the neutron spin structure in the valence quark region (the large Bjorken variable XBj region) is of particular interest. The few data that existed in the large XBj region …
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Measurement of target single-spin asymmetry in charged kaon electroproduction on a transversely polarized 3He target
The subject of quark transverse spin and transverse momentum distribution are two current research frontier in understanding the spin structure of the nucleons. The goal of the research reported in this dissertation is to extract new information on the quark transversity distribution and the novel …
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Measuring the Neutron Spin Asymmetry A1n in the Valence Quark Region in Hall C at Jefferson Lab
The quest to understand how the nucleon spin is decomposed into its constituent quark and gluon spin and orbital angular momentum (OAM) components has been at the forefront of nuclear physics for decades. Due to the non-perturbative nature of Quantum Chromodynamics (QCD) - the theory describing how …
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Double spin asymmetry AL̳T̳ in charged pion production from deep inelastic scattering on a transversely polarized ³He target
… the first measurement of the beam-target double-spin asymmetry ALT for charged pion electroproduction in deep inelastic electron scattering on a transversely polarized 3He target. These data were taken between October 2008 to February 2009 using a 5.9 GeV polarized electron beam at Thomas …
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Longitudinal double spin asymmetry for inclusive jet production in polarized proton-proton collisions at [square root of] s = 200 GeV
We present the Inclusive Jet Longitudinal Double-Spin Asymmetry for polarized protons at \s = 200 GeV. The data were taken on the STAR experiment at RHIC during the 2005 run period and cover a jet transverse momentum range of 5 < pT < 30 GeV/c. The main detector components used were the …
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Longitudinal double-spin asymmetry and cross section for inclusive neutral pion production in polarized proton collisions at [the square root of sigma] = 200 GeV.
… have found that the contribution from quark spins (1/2[delta] [sigma]) to the spin of the proton is only ~ 35%. This has lead researchers to look elsewhere, specifically to gluon spin ([delta sigma]) for a large contribution to proton spin. [delta sigma] has been only loosely constrained in …
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Gluon polarization in the proton: constraints at low x from the measurement of the double longitudinal spin asymmetry for forward-rapidity hadrons with the PHENIX detector at RHIC
… revealed that only about a third of the proton's spin of $\frac{1}{2}\hbar$ is carried by the quarks and antiquarks, leaving physicists with the puzzle of how to account for the remaining spin. As gluons carry roughly 50\% of the proton's momentum, it seemed most logical to look to the gluon spin …
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Electroproduction of Neutral Pion Off Helium-4
… The goal of this work is to extract the beam-spin asymmetry in deeply virtual coherent neutral pion electroproduction, <em>e</em><sup>4</sup>He → <em>e′</em><sup>4</sup>He′π<sup>0</sup>, using the CLAS detector in the experimental Hall B at Thomas Jefferson National Accelerator Facility. The …
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Exclusive Production of Quarkonia and Generalized Parton Distributions
… we looked at are the unpolarized cross section, spin density matrix elements, and two spin-asymmetries --- the transverse single-spin asymmetry An, and a newly discussed double-spin asymmetry ALS, which we identified as a very promising observable for measuring Eg. We find that in the case of J/ψ …
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Spin Dependence in Polarized Proton-Proton Elastic Scattering at RHIC
… with the unique capability of RHIC to collide spin-polarized proton beams, allows STAR to study both the dynamics and the spin-dependence of the proton-proton (<em> pp</em>) elastic scattering process. Silicon strip detectors, installed inside the Roman Pots, measure tracks of protons scattered …
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Double helicity asymmetry for charged pion + jet production in p+p collisions at [square root of] s=200 GeV at STAR
… larger quark polarization amplifies the measured asymmetry thereby enhancing the statistical power. This thesis presents the result of the mid-rapidity pion+jet longitudinal double spin asymmetry analysis from 10.6 pb-1 of luminosity collected in the 2009 200 GeV p+p run.
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Measurement of transverse spin asymmetries in polarized proton-proton collisions, and the realization of new electromagnetic calorimeters for forward physics
Single transverse spin asymmetries in polarized proton-proton collisions, AN , are extracted at mid-rapidity and at forward-rapidity. The forward-rapidity data is acquired with a pair of electromagnetic calorimeters which were built as part of the thesis. All aspects of the calorimeters from design …
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Inclusive jet and dijet production in polarized proton-proton collisions at [the square root of sigma] =200 GeV at RHIC
… cross section, and the dijet longitudinal double spin asymmetry ALL in polarized proton-proton collisions at [square root of sigma] = 200 GeV are measured with a data sample of 5.4 pbm collected with the STAR detector during RHIC Run-6. The inclusive cross section is measured as a function of jet …
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Feasibility study on extracting the gluon polarization in Di-Jet production in polarized pp collisions at RHIC
… National Laboratory (BNL) is carrying out a spin physics program at is = 200 - 500 GeV to gain a deeper insight into the spin structure and dynamics of the proton. These studies provide fundamental tests of Quantum Chromodynamics (QCD). One of the main objectives of the STAR spin physics …
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Neutral Pion Double Helicity Asymmetry in Polarized Proton-Proton Collisions at [the square root of sigma]=200 GeV at STAR
One of the primary goals of the spin physics program at the STAR experiment is to constrain the polarized gluon distribution function, [delta]g(X,Q²), by measuring the double longitudinal spin asymmetry, ALL, of various final-state channels. Neutral pions provide a potentially powerful final state …
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Measurement of longitudinal double spin asymmetries of [pi]+/- production in p[over-arrow] + p[over-arrow] collisions at [sqrt]s = 200 GeV at RHIC
Spin dependent measurements provide incisive tests for modern theories of particle physics. The discovery that the integral of the quark helicity distribution is much too small to account for the spin of the proton is an excellent case in point. It inspired an intense period of theoretical scrutiny …
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