Quark Wigner distributions in a light-cone spectator model

TL;DR

This paper explores the detailed internal quark structure of the proton by calculating all leading-twist Wigner distributions for u and d quarks using a light-cone spectator model, including various polarization states and rotation effects.

Contribution

It introduces a comprehensive calculation of 16 leading-twist quark Wigner distributions in a light-cone spectator model, incorporating scalar and axial-vector spectators and Melosh-Wigner rotations.

Findings

Rich visualization of quark distributions in the proton

Inclusion of polarization configurations and rotation effects

Detailed distributions for u and d quarks

Abstract

We investigate the quark Wigner distributions in a light-cone spectator model. The Wigner distribution, as a quasi-distribution function, provides the most general one-parton information in a hadron. Combining the polarization configurations, unpolarized, longitudinal polarized or transversal polarized, of the quark and the proton, we can define 16 independent Wigner distributions at leading twist. We calculate all these Wigner distributions for the $u$ quark and the $d$ quark respectively. In our calculation, both the scalar and the axial-vector spectators are included, and the Melosh-Wigner rotation effects for both the quark and the axial-vector spectator are taken into account. The results provide us a very rich picture of the quark structure in the proton.