Pre-Town Meeting on Spin Physics at an Electron-Ion Collider

TL;DR

This paper discusses the potential of the Electron--Ion Collider (EIC) to advance understanding of Quantum Chromodynamics by exploring the spin and three-dimensional structure of nucleons and nuclei, based on recent developments.

Contribution

It provides an overview of recent theoretical and experimental progress in spin physics relevant to the upcoming Electron--Ion Collider.

Findings

Advances in understanding nucleon spin structure

Progress in three-dimensional nucleon imaging

Updated theoretical models since 2012 White paper

Abstract

A polarized $ep/eA$ collider (Electron--Ion Collider, or EIC), with polarized proton and light-ion beams and unpolarized heavy-ion beams with a variable center--of--mass energy $\sqrt{s} \sim 20$ to $\sim100$~GeV (upgradable to $\sim 150$ GeV) and a luminosity up to $\sim 10^{34} \, \textrm{cm}^{-2} \textrm{s}^{-1}$, would be uniquely suited to address several outstanding questions of Quantum Chromodynamics, and thereby lead to new qualitative and quantitative information on the microscopic structure of hadrons and nuclei. During this meeting at Jefferson Lab we addressed recent theoretical and experimental developments in the spin and the three--dimensional structure of the nucleon (sea quark and gluon spatial distributions, orbital motion, polarization, and their correlations). This mini--review contains a short update on progress in these areas since the EIC White paper~\cite{Accardi:2012qut}.