# Quark Wigner distributions and spin-spin correlations

## TL;DR

This paper explores the internal spatial and spin structure of protons by calculating Wigner distributions for u and d quarks using a light-front quark-diquark model inspired by AdS/QCD, including spin correlations and GTMDs.

## Contribution

It introduces a novel calculation of quark Wigner distributions within a light-front model incorporating scalar and axial vector diquarks, and analyzes their scale evolution and spin correlations.

## Key findings

- Wigner distributions satisfy a Soffer-bound-type inequality.
- GTMDs are evaluated and their scale evolution is shown.
- Spin-spin correlations between quarks and protons are analyzed.

## Abstract

We investigate the Wigner distributions for $u$ and $d$ quarks in a light-front quark-diquark model of a proton to unravel the spatial and spin structure. The light-front wave functions are modeled from the soft-wall AdS/QCD prediction. We consider the contributions from both the scalar and the axial vector diquarks. The Wigner distributions for unpolarized, longitudinally polarized, and transversely polarized protons are presented in the transverse momentum plane as well as in the transverse impact parameter plane. The Wigner distributions satisfy a Soffer-bound-type inequality. We also evaluate all the leading twist GTMDs and show their scale evolution. The spin-spin correlations between the quark and the proton are investigated