Deeply virtual Compton scattering on longitudinally polarized protons and neutrons at CLAS

Niccolai, S.

doi:10.22323/1.157.0053

Cited by 5 publications

(4 citation statements)

References 10 publications

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“…Generalized parton distributions (GPDs) [1][2][3] which describe the parton distributions in the nucleon with transverse displacement contain important information about the nucleon such as the mass, angular momentum and mechanical properties [2,4,5] as well as the 3-dimensional (3D) structure of the nucleon [6][7][8][9]. There have been experimental measurements of deeply virtual Compton scattering (DVCS) [10] cross-sections aiming to explore GPDs at HERA (H1 [11][12][13][14], ZEUS [15,16], HERMES [17,18]) and Jefferson Lab (CLAS [19][20][21][22][23][24][25][26] and Hall A [27][28][29][30][31]) spanning decades. In addition, lattice quantum chromodynamics (QCD) provides us another opportunity to study the parton physics in the nucleon from first-principles calculations.…”

Section: Introductionmentioning

confidence: 99%

Generalized parton distributions through universal moment parameterization: zero skewness case

Guo

Shiells³

2022

J. High Energ. Phys.

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We present a global analysis program for the generalized parton distributions (GPDs) based on conformal moment expansion. We apply the strategy of universal moment parameterization to fit both the collinear parton distribution functions (PDFs) from phenomenology and generalized form factors from lattice calculations, and show that the parameterization is flexible enough to accommodate these constraints. In addition, we can also fit direct lattice calculations of GPDs from large-momentum effective theory. In this work we focus on the analysis of t-dependent PDFs which correspond to GPDs in the ξ → 0 limit. The strategy also applies to the ξ ≠ 0 region with extra parameters, and therefore can be fitted to experimental observables in the future. With a demonstrative example of fitted GPDs, we exhibit the quark transverse angular momentum densities of the proton as well as the impact parameter space distributions of quarks in both unpolarized and transversely polarized protons.

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Section: Introductionmentioning

confidence: 99%

Generalized parton distributions through universal moment parameterization: zero skewness case

Guo

Shiells³

2022

J. High Energ. Phys.

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“…In particular, proton and neutron quark GPDs have been constrained in limited kinematic regions by deeply-virtual Compton scattering (DVCS) and deeply-virtual meson production (DVMP) experiments at Thomas Jefferson National Accelerator Facility (JLab) [10], HERA [11], and COMPASS [12] (Refs. [13][14][15] summarise the world datasets).…”

Section: Introductionmentioning

confidence: 99%

Gluon gravitational form factors of the nucleon and the pion from lattice QCD

2019

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A future Electron-Ion Collider will enable the gluon contributions to the gravitational form factors of the proton to be constrained experimentally for the first time. Here, the first calculation of these form factors from lattice Quantum Chromodynamics is presented. The calculations use a largerthan-physical value of the light quark mass corresponding to mπ ∼ 450 MeV. All three form factors, which encode the momentum-dependence of the lowest moment of the spin independent gluon generalised parton distributions and are related to different components of the energy-momentum tensor, are resolved. In particular, the gluon D-term form factor, related to the pressure distribution inside the nucleon, is determined for the first time. The gluon contributions to the two gravitational form factors of the pion are also determined, and are compared to existing lattice determinations of the quark contributions to the gravitational form factors and to phenomenology. arXiv:1810.04626v1 [hep-lat]

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“…Encoded in this process are the important information of the nucleon such as the mass, angular momentum and mechanical properties [1,4,5] and the three-dimensional structure of the nucleon [6][7][8]. There have been numerous measurements from HERA (H1 [9][10][11][12], ZEUS [13,14] and HERMES [15,16]) and Jefferson Lab (JLab) (CLAS [17][18][19][20][21][22][23][24] and Hall A [25][26][27][28][29]) spanning decades, and more programs are planned in the future such as the JLab 24 GeV, EIcC [30] and EIC [31].…”

Section: Introductionmentioning

confidence: 99%

Twist-three cross-sections in deeply virtual Compton scattering

Guo

Kriesten³

et al. 2022

J. High Energ. Phys.

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We study the deeply virtual Compton scattering process with both twist-two and twist-three Compton form factors and present our cross-sections formulas with all polarization configurations. While the twist-three contributions are generally assumed to be negligible in the literature due to the kinematical suppression, we compare them with the twist-two ones at typical JLab 6 GeV and 12 GeV kinematics as well as EIC kinematics and show their kinematical suppression explicitly, justifying the leading-twist approximation made in the literature. In addition, we also estimate the twist-three Compton form factors using Wandzura-Wilczek relations and inputs of twist-two generalized parton distributions based on a reggeized spectator model. With those estimated Compton form factors, we analyze the kinematical behavior of twist-two and twist-three cross-sections in a wide range of kinematics, and discuss the optimal regions for separating the leading-twist effects from the higher-twist ones.

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Deeply virtual Compton scattering on longitudinally polarized protons and neutrons at CLAS

Cited by 5 publications

References 10 publications

Generalized parton distributions through universal moment parameterization: zero skewness case

Generalized parton distributions through universal moment parameterization: zero skewness case

Gluon gravitational form factors of the nucleon and the pion from lattice QCD

Twist-three cross-sections in deeply virtual Compton scattering

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