Border and skewness functions from a leading order fit to DVCS data
Résumé
We propose new parameterizations for the border and skewness functions appearing in the description of 3D nucleon structure in the language of generalized parton distributions (GPDs). These parameterizations are constructed in a way to fulfill the basic properties of GPDs, like their reduction to parton density functions and elastic form factors. They also rely on the power behavior of GPDs in the $x \rightarrow 1$ limit and the propounded analyticity property of Mellin moments of GPDs. We evaluate compton form factors (CFFs), the sub-amplitudes of the deeply virtual compton scattering (DVCS) process, at the leading order and leading twist accuracy. We constrain the restricted number of free parameters of these new parameterizations in a global CFF analysis of almost all existing proton DVCS measurements. The fit is performed within the PARTONS framework, being the modern tool for generic GPD studies. A distinctive feature of this CFF fit is the careful propagation of uncertainties based on the replica method. The fit results genuinely permit nucleon tomography and may give some insight into the distribution of forces acting on partons.
Mots clés
12.38.-t
13.60.-r
13.60.Fz
14.20.-c
Nucleon Structure
Generalized Parton Distribution
GPD
Skewness Function
Border Function
Analyticity
Power Behavior
Deeply Virtual Compton Scattering
DVCS
higher-order: 0
Compton scattering: form factor
generalized parton distribution
deeply virtual Compton scattering
nucleon
analytic properties
twist
parametrization
Mellin transformation
data analysis method
statistical analysis