Generalized parton distributions through universal moment parameterization: zero skewness case

We present a global analysis program for the generalized parton distributions (GPDs) based on conformal moment expansion. We apply the strategy of universal moment parameterization to fit both the collinear parton distribution functions (PDFs) from phenomenology and generalized form factors from lattice calculations, and show that the parameterization is flexible enough to accommodate these constraints. In addition, we can also fit direct lattice calculations of GPDs from large-momentum effective theory. In this work we focus on the analysis of t-dependent PDFs which correspond to GPDs in the xi -> 0 limit. The strategy also applies to the xi not equal 0 region with extra parameters, and therefore can be fitted to experimental observables in the future. With a demonstrative example of fitted GPDs, we exhibit the quark transverse angular momentum densities of the proton as well as the impact parameter space distributions of quarks in both unpolarized and transversely polarized protons.

Automated summary

We present a global analysis program based on conformal moment expansion for the generalized parton distributions (GPDs). We use the strategy of universal moment parameterization to fit both the collinear parton distribution functions (PDFs) from phenomenology and generalized form factors from lattice calculations. The parameterization is flexible enough to accommodate these constraints, and can also fit direct lattice calculations of GPDs from large-momentum effective theory. We focus on analyzing t-dependent PDFs in this work, which correspond to GPDs in the xi -> 0 limit. The strategy also applies to the xi not equal 0 region with extra parameters, and can be fitted to experimental observables in the future. Through a demonstrative example, we show the quark transverse angular momentum densities of the proton and the impact parameter space distributions of quarks in both unpolarized and transversely polarized protons.