180 research outputs found

    Helicity-dependent generalized parton distributions for nonzero skewness

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    We investigate the helicity dependent generalized parton distributions (GPDs) in momentum as well as transverse position (impact) spaces for up and down quarks in a proton when the momentum transfer in both the transverse and longitudinal directions are nonzero. The GPDs are evaluated using the light-front wavefunctions of a quark-diquark model for nucleon where the wavefunctions are constructed by the soft-wall AdS/QCD correspondence. We also express the GPDs in the boost-invariant longitudinal position space.Comment: 13 pages, 10 figures; to appear in Eur. Phys. J. C. arXiv admin note: text overlap with arXiv:1509.0059

    Longitudinal momentum densities in transverse plane for nucleons

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    We present a study of longitudinal momentum densities (p+densitiesp^+ \rm densities) in the transverse impact parameter space for uu and dd quarks in both unpolarized and transversely polarized nucleons by taking a two dimensional Fourier transform of the gravitational form factors with respect to the momentum transfer in the transverse direction. The gravitational form factors are obtained by the second moments of GPDs. Here we consider the GPDs of two different soft-wall models in AdS/QCD correspondence.Comment: 12 pages, 9 figures; text modifie

    Nucleon to Δ\Delta transition form factors and empirical transverse charge densities

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    We investigate the nucleon to Δ\Delta transition form factors in a soft-wall AdS/QCD model and a light-front quark-diquark model inspired by AdS/QCD. From the transition form factors we evaluate the transition charge densities which influences the nucleon to Δ\Delta excitation. Here we consider both the unpolarized and the transversely polarized cases. The AdS/QCD predictions are compared with available experimental data and with the results of the global parameterization, MAID2007.Comment: 9 pages, 5 figures; minor text modified, version to appear in Eur. Phys. J.

    Nucleon and flavor form factors in a light front quark model in AdS/QCD

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    Using the light front wave functions for the nucleons in a quark model in AdS/QCD, we calculate the nucleon electromagnetic form factors. The flavor decompositions of the nucleon form factors are calculated from the GPDs in this model. We show that the nucleon form factors and their flavor decompositions calculated in AdS/QCD are in agreement with experimental data.Comment: To appear in Eur. Phys. J. C; The final publication is available at link.springer.co

    Wigner distributions for an electron

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    We study the Wigner distributions for a physical electron, which reveal the multidimensional images of the electron. The physical electron is considered as a composite system of a bare electron and photon. The Wigner distributions for unpolarized, longitudinally polarized and transversely polarized electron are presented in transverse momentum plane as well as in impact parameter plane. The spin-spin correlations between the bare electron and the physical electron are discussed. We also evaluate all the leading twist generalized transverse momentum distributions (GTMDs) for electron.Comment: 27 pages, 18 figures, text modified, version accepted in Nuclear Physics

    Transverse charge and magnetization densities in holographic QCD

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    We present a study of flavor structures of transverse charge and anomalous magnetization densities for both unpolarized and transversely polarized nucleons. We consider two different models for the electromagnetic form factors in holographic QCD. The flavor form factors are obtained by decomposing the Dirac and Pauli form factors for nucleons using the charge and isospin symmetry. The results are compared with two standard phenomenological parametrizations.Comment: minor modifications, some references correcte
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