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 ($\chi$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 $x$ by including it phenomenologically in the sea quark distribution functions. The results for the quark sea asymmetries like $\bar d(x)-\bar u(x)$, $\bar d(x)/\bar u(x)$ and Gottfried integral for the octet baryons strengthen the significance of quark sea at lower values of $x$.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