7,712 research outputs found
Longitudinal and Transverse Parton Momentum Distributions for Hadrons within Relativistic Constituent Quark Models
Longitudinal and transverse parton distributions for pion and nucleon are
calculated from hadron vertexes obtained by a study of form factors within
relativistic quark models. The relevance of the one-gluon-exchange dominance at
short range for the behavior of the form factors at large momentum transfer and
of the parton distributions at the end points is stressed.Comment: 5 pages, 4 figs. Proceedings of Hadron 09, to appear in AIP
Conference Proceeding
Probing the parton content of the nucleon
The parton content of the nucleon is explored within a meson-cloud model
developed to derive light-cone wave functions for the physical nucleon. The
model is here applied to study electromagnetic form factors, distribution
amplitudes and nucleon-to-meson transition distribution amplitudes.Comment: 10 pages, 6 figures; proceedings of the workshop "Recent Advances in
Perturbative QCD and Hadronic Physics" in Honor of Prof. Anatoly Efremov's
75th Birthday Celebration; to appear in Mod. Phys. Lett.
The pion electromagnetic form-factor in a QCD-inspired model
We present detailed numerical results for the pion space-like electromagnetic
form factor obtained within a recently proposed model of the pion
electromagnetic current in a confining light-front QCD-inspired model. The
model incorporates the vector meson dominance mechanism at the quark level,
where the dressed photon with decay in an interacting quark-antiquark
pair,wich absorbs the initial pion and produces the pion in the final state.Comment: Talk given in Light-Cone 2004, Amsterdam,NL., 16-20 August, 2004. To
appear in "Few-Body Systems". 4 pages, 2 figues eps, use Few-Body Sytems
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Light-front quark distributions in the nucleon and nucleon electromagnetic form factors
Longitudinal and transverse quark momentum distributions in the nucleon are
calculated from a phenomenological quark-nucleon vertex function obtained
through an investigation of the nucleon electromagnetic form factors within a
light-front framework.Comment: 6 pages, 11 figs. proceedings of LC2009, to appear in Nucl. Phys.
Timelike and spacelike hadron form factors, Fock state components and light-front dynamics
A unified description of spacelike and timelike hadron form factors within a
light-front model was successfully applied to the pion. The model is extended
to the nucleon to study the role of pair production and of
nonvalence components in the nucleon form factors. Preliminary results in the
spacelike range are presented.Comment: 4 pages, espcrc1.sty. proceedings of FB XVIII (August 2006, Brazil),
to be published in Nucl. Phys.
Electromagnetic Hadron Form Factors and Higher Fock Components
Investigation of the spacelike and timelike electromagnetic form factors of
hadrons, within a relativistic microscopical model characterized by a small set
of hypothesis, could shed light on the components of hadron states beyond the
valence one. Our relativistic approach has been successfully applied first to
the pion and then the extension to the nucleon has been undertaken. The pion
case is shortly reviewed as an illustrative example for introducing the main
ingredients of our approach, and preliminary results for the nucleon in the
spacelike range are evaluated.Comment: 8 pages, 6 figs, espcrc1.sty included. Proceedings of Fifth
International Conference on Perspectives In Hadronic Physics, ICTP, May
22-26, 200
Electromagnetic form factors of the nucleon in spacelike and timelike regions
An approach for a unified description of the nucleon electromagnetic form
factors in spacelike and timelike regions is presented. The main ingredients of
our model are: a Mandelstam formula for the matrix elements of the nucleon
electromagnetic current; a 3-dimensional reduction of the problem on the
Light-Front performed within the so-called {\tt Propagator Pole Approximation}
({\bf PPA}), which consists in disregarding the analytical structure of the
Bethe-Salpeter amplitudes and of the quark-photon vertex function in the
integration over the minus components of the quark momenta; a dressed
photon vertex in the channel, where the photon is described by its
spin-1, hadronic component.Comment: 8 pages, 9 figs., macro added. Proceedings of the XI Conf. on
Problems in Theoretical Nuclear Physics, Cortona, Oct. 11-14, 200
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