58 research outputs found
Momentum transfer dependence of generalized parton distributions
We revisit the model for parametrization of momentum dependence of nucleon
generalized parton distributions in the light of recent MRST measurements of
parton distribution functions. Our parametrization method with minimum set of
free parameters give a sufficiently good description of data for Dirac and
Pauli electromagnetic form factors of proton and neutron at small and
intermediate values of momentum transfer. We also calculate the GPDs for up and
down quark by decomposing the electromagnetic form factors for nucleon using
the charge and isospin symmetry and also study the evolution of GPDs to a
higher scale. We further investigate the transverse charge densities for both
the unpolarized and transversely polarized nucleon and compare our results with
the Kelly's distribution
Hard gluon evolution of nucleon Generalized parton distributions in the Light-front quark model
We incorporate the perturbative evolution effects in the generalized parton
distributions (GPDs) calculated in effective light-front quark model for the
nucleon. The perturbative effects enters into formalism through the evolution
of GPDs according to the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi-like
(DGLAP) equation. We obtain the evolved GPDs in the momentum space and
transverse impact parameter space. We observe that combining the light front
quark model with the perturbative evolution effects, give the effective model
for studying the phenomenological GPD
Chiral symmetry breaking and electromagnetic structure of the nucleon
The electromagnetic form factors are the most fundamental quantities to
describe the internal structure of the nucleon and are related to the charge
radii of the baryons. We have calculated the charge radii of octet baryons in
the framework of chiral constituent quark model with the inclusion of the
spin-spin generated configuration mixing. This model is quite successful in
predicting the low energy hadron matrix elements. The results obtained in the
case of charge radii are also comparable to the latest experimental studies and
show improvement over some theoretical interpretations.Comment: 5 pages. Prepared for the proceedings of the Chiral10 International
Workshop on Chiral Symmetry in Hadrons and Nuclei, Valencia, SPAIN, June
21-24, 201
Nonperturbative Quark Sea Asymmetries
The effects of nonperturbatively generated ``quark sea'' have been
investigated to determine the flavor structure of the octet baryons. The chiral
constituent quark model (CQM), which is known to provide a satisfactory
explanation of the proton spin and related issues in the nonperturbative
regime, is able to explain the qualitative generation of the requisite amount
of quark sea. The importance of quark sea has been studied at different values
of the Bjorken scaling variable by including it phenomenologically in the
sea quark distribution functions. The results for the quark sea asymmetries
like , and Gottfried integral for
the octet baryons strengthen the significance of quark sea at lower values of
.Comment: 9 pages. Presented at the Gribov-80 Memorial Workshop on Quantum
Chromodynamics and Beyond held at ICTP, Trieste in May 2010. (To appear in
the World Scientific Proceedings
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