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Your search keyword '"Liuti, Simonetta"' showing total 4 results
4 results on '"Liuti, Simonetta"'

1. Probing Spin Dependent Quark and Gluon Distributions Through Azimuthal and Polarization Asymmetries.

Author

Goldstein, Gary R. and Liuti, Simonetta

Subjects
*PARTONS, *NUCLEAR particle research, *QUARKS, *HADRONS, *PHYSICS research
Abstract

Spin and transverse momentum dependent parton distributions - Generalized Parton Distributions, Transverse Momentum Distributions and related distributions - are at the interface between the QCD structure of the hadrons and observable quantities. The distributions are contained as linear superpositions within helicity amplitudes that factorize into universal forms at leading or next to leading order. These amplitudes are probed in high energy leptoproduction processes through angular dependent cross sections and polarization asymmetries. The phenomenological extraction of the amplitudes and the distributions is a challenging task. We will present some models for the distributions in leptoproduction processes, as well as the observables that connect with the quark-nucleon helicity amplitudes for different Deeply Virtual production possibilities. [ABSTRACT FROM AUTHOR]

Published
2016
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2. Interpretation of the flavor dependence of nucleon form factors in a generalized parton distribution model.

Author

Gonzalez-Hernandez, J. Osvaldo, Liuti, Simonetta, Goldstein, Gary R., and Kathuri, Kunal

Subjects
*PARTICLES (Nuclear physics), *ELECTROMAGNETIC form factors, *MOMENTUM transfer, *QUARKS, *PARTONS, *ANGULAR momentum (Mechanics)
Abstract

We give an interpretation of the u and d quarks contributions to the nucleon electromagnetic form factors for values of the four-momentum transfer in the multi-GeV region where flavor separated data have been recently made available. The data show, in particular, a suppression of d quarks with respect to u quarks at large momentum transfer. This trend can be explained using a reggeized diquark model calculation of generalized parton distributions, thus providing a correlation between momentum and coordinate spaces, both of which are necessary to interpret the partonic substructure of the form factors. We extend our discussion to the second moments of generalized parton distributions which are believed to contribute to partonic angular momentum. [ABSTRACT FROM AUTHOR]

Published
2013
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3. Flexible parametrization of generalized parton distributions: The chiral-odd sector.

Author

Goldstein, Gary R., Hernandez, J. Osvaldo Gonzalez, and Liuti, Simonetta

Subjects
*PARTONS, *PHYSICAL measurements, *QUARKS, *INELASTIC scattering, *MESONS, *DIQUARKS, *HYPOTHETICAL composite particles, SCATTERING
Abstract

We present a physically motivated parametrization of the chiral-odd generalized parton distributions. The parametrization is an extension of our previous one in the chiral-even sector which was based on the Reggeized diquark model. While for chiral-even generalized distributions a quantitative fit with uncertainty estimation can be performed using deep inelastic scattering data, nucleon electromagnetic, axial and pseudoscalar form factors measurements, and all available deeply virtual Compton scattering data, the chiral-odd sector is far less constrained. While awaiting the analysis of measurements on pseudoscalar mesons exclusive electroproduction which are key for the extraction of chiral-odd GPDs, we worked out a connection between the chiral-even and chiral-odd reduced helicity amplitudes using parity transformations. The connection works for quark-parton models including both scalar and axial vector diquark models, and spectator models in general. This relation allows us to estimate the size of the various chiral-odd contributions and it opens the way for future quantitative fits. [ABSTRACT FROM AUTHOR]

Published
2015
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4. Quark-hadron duality in structure functions.

Author

Fantoni, Alessandra, Bianchi, Nicola, and Liuti, Simonetta

Subjects
*QUARKS, *PARTICLES (Nuclear physics), *QUARK confinement, *HADRONS, *BARYONS, *PARTONS
Abstract

The quark-hadron duality is studied in a systematic way for polarized and unpolarized structure functions, by taking into account all the available data in the resonance region. In both cases, a precise perturbative QCD based analysis to the integrals of the structure functions in the resonance region has been done: non perturbative contributions have been disentangled and the higher twist contributions have been evaluated. A different behavior for the unpolarized and polarized structure functions at lowQ2 has been found.PACS:quark-hadron duality - structure functions [ABSTRACT FROM AUTHOR]

Published
2005
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