Parametrization of Generalized Parton Distributions from t-Channel String Exchange in AdS Spaces.

Area of Science:

• Nuclear Physics
• Particle Physics
• Quantum Chromodynamics

Background:

• Generalized Parton Distributions (GPDs) are crucial for understanding nucleon structure.
• Current models often face limitations with skewness dependence.
• Accurate GPD parametrization is essential for interpreting exclusive deep inelastic scattering experiments.

Purpose of the Study:

• To introduce a novel, model-independent string-based parametrization for nucleon quark and gluon GPDs.
• To develop a framework valid across all skewness values.
• To enhance the empirical extraction and global analysis of GPDs.

Main Methods:

• Utilizing conformal moments and representing GPDs as sums of spin-j nucleon A- and D-form factors.
• Deriving form factors from t-channel string exchange in Anti-de Sitter (AdS) spaces, ensuring Lorentz invariance and unitarity.
• Employing Mellin moments from empirical data to estimate form factors within a polynomiality-satisfying framework.
• Using Mellin-Barnes integrals with five Regge slope parameters to generate GPDs.

Main Results:

• Accurate production of various nucleon quark GPD types and symmetric nucleon gluon GPDs.
• Isovector nucleon quark GPD results show agreement with existing lattice data.
• The method successfully avoids the deconvolution problem for GPDs at any skewness.

Conclusions:

• The string-based parametrization offers a robust and versatile tool for nucleon structure studies.
• This approach significantly advances the ability to analyze GPDs in exclusive processes.
• It provides a first-time solution for handling GPD deconvolution across all skewness regimes.