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

Elke-Caroline Aschenauer, Ian Balitsky, Leslie Bland, Stanley J. Brodsky, Matthias Burkardt, Volker Burkert, Jian-Ping Chen, Abhay Deshpande, Markus Diehl, Leonard Gamberg, Matthias Grosse Perdekamp, Jin Huang, Charles Hyde, Xiangdong Ji, Xiaodong Jiang, Zhong-Bo Kang, Valery Kubarovsky, John Lajoie, Keh-Fei Liu, Ming Liu, Simonetta Liuti, Wally Melnitchouk, Piet Mulders, Alexei Prokudin, Andrey Tarasov, Jian-Wei Qiu, Anatoly Radyushkin, David Richards, Ernst Sichtermann, Marco Stratmann, Werner Vogelsang, Feng Yuan

Published 2014-10-31Version 1

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}.