This White Paper presents the science case of an Electron-Ion Collider (EIC), focused on the structure and interactions of gluon-dominated matter, with the intent to articulate it to the broader nuclear science community. It was commissioned by the managements of Brookhaven National Laboratory (BNL) and Thomas Jefferson National Accelerator Facility (JLab) with the objective of presenting a summary of scientific opportunities and goals of the EIC as a follow-up to the 2007 NSAC Long Range plan. This document is a culmination of a community-wide effort in nuclear science following a series of workshops on EIC physics over the past decades and, in particular, the focused ten-week program on “Gluons and quark sea at high energies” at the Institute for Nuclear Theory in Fall 2010. It contains a brief description of a few golden physics measurements along with accelerator and detector concepts required to achieve them. It has been benefited profoundly from inputs by the users’ communities of BNL and JLab. This White Paper offers the promise to propel the QCD science program in the US, established with the CEBAF accelerator at JLab and the RHIC collider at BNL, to the next QCD frontier.

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Electron-Ion Collider: The next QCD frontier: Understanding the glue that binds us all

We study in QCD the physics of deeply virtual Compton scattering (DVCS){emdash}the virtual Compton process in the large s and small t kinematic region. We show that DVCS can probe a new type of {ital off-forward} parton distributions. We derive an Altarelli-Parisi-type of evolution equations for these distributions. We also derive their sum rules in terms of nucleon form factors of the twist-two quark and gluon operators. In particular, we find that the second sum rule is related to fractions of the nucleon spin carried separately by quarks and gluons. We estimate the cross section for DVCS and compare it with the accompanying Bethe-Heitler process at CEBAF and HERMES kinematics. {copyright} {ital 1997} {ital The American Physical Society}

Deeply Virtual Compton Scattering

Baryon chiral perturbation theory using a heavy fermion lagrangian

The g1 problem: Deep inelastic electron scattering and the spin of the proton☆

This article reviews our present understanding of QCD spin physics: the proton spin puzzle and new developments aimed at understanding the transverse structure of the nucleon. Present experimental investigations of the nucleon's internal spin structure, the theoretical interpretation of the different measurements, and the open questions and challenges for future investigation are discussed.

/pdf/the-spin-structure-of-the-nucleon-4938rrpltt.pdf

The Spin Structure of the Nucleon

https://cds.cern.ch/record/198545/files/198908347.pdf

L. Urban

Papers

An investigation of the spin structure of the proton in deep inelastic scattering of polarised muons on polarised protons