Single and Double Spin Asymmetries for Deeply Virtual Compton Scattering Measured with CLAS and a Longitudinally Polarized Proton Target

Single and Double Spin Asymmetries for Deeply Virtual Compton Scattering Measured with CLAS and a Longitudinally Polarized Proton Target PDF Author:
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Languages : en
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Book Description
Single-beam, single-target, and double-spin asymmetries for hard exclusive photon production on the proton e→p→e'p'[gamma] are presented. The data were taken at Jefferson Lab using the CLAS detector and a longitudinally polarized 14NH3 target. The three asymmetries were measured in 165 4-dimensional kinematic bins, covering the widest kinematic range ever explored simultaneously for beam and target-polarization observables in the valence quark region. The kinematic dependences of the obtained asymmetries are discussed and compared to the predictions of models of Generalized Parton Distributions. As a result, the measurement of three DVCS spin observables at the same kinematic points allows a quasi-model-independent extraction of the imaginary parts of the H and H~ Compton Form Factors, which give insight into the electric and axial charge distributions of valence quarks in the proton.

Single and Double Spin Asymmetries for Deeply Virtual Compton Scattering Measured with CLAS and a Longitudinally Polarized Proton Target

Single and Double Spin Asymmetries for Deeply Virtual Compton Scattering Measured with CLAS and a Longitudinally Polarized Proton Target PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
Single-beam, single-target, and double-spin asymmetries for hard exclusive photon production on the proton e→p→e'p'[gamma] are presented. The data were taken at Jefferson Lab using the CLAS detector and a longitudinally polarized 14NH3 target. The three asymmetries were measured in 165 4-dimensional kinematic bins, covering the widest kinematic range ever explored simultaneously for beam and target-polarization observables in the valence quark region. The kinematic dependences of the obtained asymmetries are discussed and compared to the predictions of models of Generalized Parton Distributions. As a result, the measurement of three DVCS spin observables at the same kinematic points allows a quasi-model-independent extraction of the imaginary parts of the H and H~ Compton Form Factors, which give insight into the electric and axial charge distributions of valence quarks in the proton.

Deeply Virtual Compton Scattering on Longitudinally Polarized Protons and Neutrons at CLAS.

Deeply Virtual Compton Scattering on Longitudinally Polarized Protons and Neutrons at CLAS. PDF Author:
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Languages : en
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Book Description
This paper focuses on a measurement of deeply virtual Compton scattering (DVCS) performed at Jefferson Lab using a nearly-6-GeV polarized electron beam, two longitudinally polarized (via DNP) solid targets of protons (NH3) and deuterons (ND3) and the CEBAF Large Acceptance Spectrometer. Here, preliminary results for target-spin asymmetries and double (beam-target) asymmetries for proton DVCS, as well as a very preliminary extraction of beam-spin asymmetry for neutron DVCS, are presented and linked to Generalized Parton Distributions.

Target-spin Asymmetry Measurements for Deeply Virtual Compton Scattering on Longitudinally Polarized Protons

Target-spin Asymmetry Measurements for Deeply Virtual Compton Scattering on Longitudinally Polarized Protons PDF Author: Erin E. Seder
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Category :
Languages : en
Pages : 239

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Longitudinal Target-spin Asymmetries for Deeply Virtual Compton Scattering

Longitudinal Target-spin Asymmetries for Deeply Virtual Compton Scattering PDF Author:
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Languages : en
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A measurement of the electroproduction of photons off protons in the deeply inelastic regime was performed at Jefferson Lab using a nearly 6-GeV electron beam, a longitudinally polarized proton target and the CEBAF Large Acceptance Spectrometer. Target-spin asymmetries for ep → e'p'y events, which arise from the interference of the deeply virtual Compton scattering and the Bethe-Heitler processes, were extracted over the widest kinematics in Q2, xB, t and [Phi], for 166 four-dimensional bins. In the framework of Generalized Parton Distributions (GPDs), at leading twist the t dependence of these asymmetries provides insight on the spatial distribution of the axial charge of the proton, which appears to be concentrated in its center. In conclusion, these results bring important and necessary constraints for the existing parametrizations of chiral-even GPDs.

Measurement of Single and Double Spin Asymmetries in Deep Inelastic Pion Electroproduction with a Longitudinally Polarized Target

Measurement of Single and Double Spin Asymmetries in Deep Inelastic Pion Electroproduction with a Longitudinally Polarized Target PDF Author:
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Languages : en
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Book Description
We report the first measurement of the transverse momentum dependence of double spin asymmetries in semi-inclusive production of pions in deep inelastic scattering off the longitudinally polarized proton. Data have been obtained using a polarized electron beam of 5.7 GeV with the CLAS detector at the Thomas Jefferson National Accelerator Facility (JLab). A significant non-zero $\sin2\phi$ single spin asymmetry was also observed for the first time indicating strong spin-orbit correlations for transversely polarized quarks in the longitudinally polarized proton. The azimuthal modulations of single spin asymmetries have been measured over a wide kinematic range.

Target and Double Spin Asymmetries of Deeply Virtual [pi]0 Production with a Longitudinally Polarized Proton Target and CLAS.

Target and Double Spin Asymmetries of Deeply Virtual [pi]0 Production with a Longitudinally Polarized Proton Target and CLAS. PDF Author:
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Category :
Languages : en
Pages : 6

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Book Description
The target and double spin asymmetries of the exclusive pseudoscalar channel $\vec e\vec p\to ep\pi^0$ were measured for the first time in the deep-inelastic regime using a longitudinally polarized 5.9 GeV electron beam and a longitudinally polarized proton target at Jefferson Lab with the CEBAF Large Acceptance Spectrometer (CLAS). The data were collected over a large kinematic phase space and divided into 110 four-dimensional bins of $Q^2$, $x_B$, $-t$ and $\phi$. Large values of asymmetry moments clearly indicate a substantial contribution to the polarized structure functions from transverse virtual photon amplitudes. The interpretation of experimental data in terms of generalized parton distributions (GPDs) provides the first insight on the chiral-odd GPDs $\tilde{H}_T$ and $E_T$, and complement previous measurements of unpolarized structure functions sensitive to the GPDs $H_T$ and $\bar E_T$. Finally, these data provide necessary constraints for chiral-odd GPD parametrizations and will strongly influence existing theoretical handbag models.

Single and Double Polarization Asymmetries from Deeply Virtual Exclusive Pi^0 Electroproduction

Single and Double Polarization Asymmetries from Deeply Virtual Exclusive Pi^0 Electroproduction PDF Author:
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Languages : en
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Book Description
The target and double spin asymmetry measurements of exclusive p0 electroproduction were performed for the first time in DIS region at Jefferson Lab using the CEBAF Large Acceptance Spectrometer (CLAS) and longitudinally polarized proton target. The wide kinematic coverage and good resolution of CLAS allowed measurements in full azimuthal range providing an opportunity to extract single and double spin asymmetries proportional to polarized structure functions. Their angular dependencies in hadronic center-of-mass system were analyzed, and extracted moments are compared to recent theoretical handbag-based calculations based on chiral-even and chiral-odd GPDs contributions. The interpretation of present results within the framework of the modified perturbative approach and their use as a constraint for models of the t behavior will be discussed.

Measurement of Single and Double Spin Asymmetries in Semi-inclusive Deep-inelastic Scattering on Proton and Deuteron

Measurement of Single and Double Spin Asymmetries in Semi-inclusive Deep-inelastic Scattering on Proton and Deuteron PDF Author: Suman Bandhu Koirala
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Category : Deuterons
Languages : en
Pages : 293

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Single--Spin Asymmetries in the Bethe--Heitler Process E− + P 2!e− + [gamma] + P from QED Radiative Corrections

Single--Spin Asymmetries in the Bethe--Heitler Process E− + P 2!e− + [gamma] + P from QED Radiative Corrections PDF Author:
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Languages : en
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Book Description
We derived analytic formulae for the polarization single--spin asymmetries (SSA) in the Bethe--Heitler process e− + p → e− + [gamma] + p. The asymmetries arise due to one-loop QED radiative corrections to the leptonic part of the interaction and present a systematic correction for the studies of virtual Compton Scattering on a proton through interference with the Bethe-Heitler amplitude. Considered are SSA with either longitudinally polarized electron beam or a polarized proton target. The computed effect appears to be small, not exceeding 0.1 percent for kinematics of current virtual Compton scattering experiments.

Deeply Virtual Compton Scattering with CLAS12

Deeply Virtual Compton Scattering with CLAS12 PDF Author:
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Languages : en
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Book Description
An overview is given about the capabilities provided by the JLab 12 GeV Upgrade to measure deeply virtual exclusive processes with high statistics and covering a large kinematics range in the parameters that are needed to allow reconstruction of a spatial image of the nucleon's quark structure. The measurements planned with CLAS12 will cross section asymmetries with polarized beams and with longitudinally and transversely polarized proton targets in the constrained kinematics $x = \pm \xi$. In addition, unpolarized DVCS cross sections, and doubly polarized beam target asymmetries will be measured as well. In this talk only the beam and target asymmetries will be discussed.