Momentum transfer dependence of generalized parton distributions

TL;DR

This paper refines a model for nucleon generalized parton distributions (GPDs) by incorporating recent data, enabling accurate descriptions of electromagnetic form factors and transverse charge densities, and studying their evolution with scale.

Contribution

It introduces a minimal-parameter parametrization of GPDs that fits experimental data and explores their scale evolution and transverse charge densities.

Findings

Good fit to proton and neutron form factors at small and intermediate momentum transfer.

Calculated GPDs for up and down quarks using symmetry decompositions.

Analyzed transverse charge densities and compared with existing distributions.

Abstract

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.