Rapidity-Dependent Spin Decomposition of the Nucleon

Abstract

We show that the two-dimensional Fourier transform of the generalized parton distributions (GPDs) has two distinct interpretations: at zero skewness ($\eta =0$) it yields the familiar impact-parameter density, while at finite skewness ($\eta \ne 0$) it encodes a genuine parton-nucleon correlation whose norm decreases predictably with the rapidity gap $\Delta y=2\mathrm{artanh}\eta$. This rapidity dependence produces universal rapidity-modified Ji identities linking helicity, orbital, and total angular momenta analytically. Using linear open- and closed string Regge trajectories constrained by empirical PDFs, spectroscopy and form factor data, we obtain the leading twist GPDs $H,E,\tilde{H}$ across the full $(x,\eta ,t)$ range. Numerical Mellin Barnes inversion agrees with existing lattice data and yields rapidity resolved predictions for Jefferson Lab 12 GeV, the Electron Ion Collider, and forthcoming lattice studies.

v1: 7 pages, 5 figures; v2: restructured manuscript, published version

References in corpus (26)

• Parton distributions for the LHC
• Wave Functions, Evolution Equations and Evolution Kernels from Light-Ray Operators of QCD
• Generalized Parton Distributions
• Unraveling hadron structure with generalized parton distributions
• Impact Parameter Space Interpretation for Generalized Parton Distributions
• The Pomeron and Gauge/String Duality
• Generalized parton distributions in impact parameter space
• Light-Cone Representation of the Spin and Orbital Angular Momentum of Relativistic Composite Systems
• Nucleon Generalized Parton Distributions from Full Lattice QCD
• GPD phenomenology and DVCS fitting - Entering the high-precision era
• Complete flavor decomposition of the spin and momentum fraction of the proton using lattice QCD simulations at physical pion mass
• Towards a fitting procedure for deeply virtual Compton scattering at next-to-leading order and beyond
• Unpolarized and helicity generalized parton distributions of the proton within lattice QCD
• Quark spins and Anomalous Ward Identity
• Up, down, and strange nucleon axial form factors from lattice QCD
• Complex conformal spin partial wave expansion of generalized parton distributions and distribution amplitudes
• Holographic Pomeron and the Schwinger Mechanism
• Determination of polarized parton distribution functions with recent data on polarization asymmetries
• Spin-orbit correlations in the nucleon
• Odderon in Gauge/String Duality
• Entanglement in Reggeized Scattering using AdS/CFT
• Systematic Improvement of $x$-dependent Unpolarized Nucleon Generalized Parton Distribution in Lattice-QCD Calculation
• Moments of Axial-Vector GPD from Lattice QCD: Quark Helicity, Orbital Angular Momentum, and Spin-Orbit Correlation
• Parametrization of GPDs from t-channel string exchange in AdS spaces
• String-based parametrization of nucleon GPDs at any skewness: a comparison to lattice QCD
• String-based axial and helicity-flip GPDs: a comparison to lattice QCD