1. Future Opportunities at an Electron-Ion Collider Oleg Eyser Brookhaven National Laboratory

2. Exploring the Glue that Binds Us All  Questions at the next QCD frontier o How are the sea quarks and gluons, and their spins, distributed in space and momentum inside the nucleon? o Where does the saturation of gluon densities set in? o How does the nuclear environment affect the distribution of quarks and gluons and their interactions in nuclei?  An Electron-Ion Collider o Electron beams for precision measurements o Polarized nucleon beams o Heavy ion beams of different species o Kinematic reach into the gluon dominated regime o Dedicated hermetic detector setup 2

3. The Structure of the Nucleon  What is the dynamical origin of sea quarks and gluons inside the proton?  How does the proton spin originate at the microscopic level?  How is hadron structure influenced by chiral symmetry and its breaking?  How does confinement manifest itself in the structure of hadrons? 3

4. Partonic Descriptions of the Nucleon 4

5. Deep Inelastic Scattering Lorentz invariants In the collider frame Other variables 5

6. Structure Functions 6

7. Longitudinal Spin Structure 7

8. 8

9. Quark TMD Distributions in SIDIS 9

10. Quark TMD Distributions 10

11. Spatial Imaging of Nucleons Fourier transform of at Exclusive processes Resolution scale 11

12. Deeply Virtual Compton Scattering 12

13. Towards Spatial Imaging 13 Combine with next slide???

14. Gluon Distributions 14

15. The Nucleus: A Laboratory for QCD  What is the role of strong gluon fields, parton saturation effects, and collective gluon excitations in nuclei?  Can we experimentally find evidence of non-linear QCD dynamics in the high-energy scattering off nuclei?  What are the momentum/spatial distributions of gluons and sea quarks in nuclei?  Are there strong color fluctuations inside a large nucleus? 15

16. High Gluon Densities in Nuclei 16

17. Lepton-Nucleus Scattering 17

18. Nuclear PDFs Expect strong non-linear effects in FL from higher twist contributions Dipole model from Bartels et al. Quantify by 18

19. Nuclear PDFs 19

20. Di-hadron Correlations PRD 83, 1 5005 (2011) PRL 106, 022301 (2011) Prediction in CGC frameworkExpected experimental significance withEPS09 (nPDF shadowing) PYTHIA6 (partons, showers, fragmentation) DPMJet-III (nuclear geometry) 20

21. Diffractive Scattering 21

22. Exclusive Vector Meson Production 22

23. Spatial Gluon Distribution 23

24. 24

25. ERL eRHIC Electron beam energy10 GeV Proton beam energy250 GeV Ion beam energy100 GeV/A Electron beam polarization80% Proton beam polarization70% 25

26. MEIC Electron beam energy5 GeV Proton beam energy60 GeV Ion beam energy40 GeV/A Electron beam polarization80% Proton beam polarization70% 26

27. DIS Kinematics 27

28. SIDIS Kinematics Non-exclusive pion 28

29. DVCS Kinematics 29 Photon in lab. frame 5 GeV x 100 GeV10 GeV x 100 GeV20 GeV x 100 GeV

30. Detector Layout Solenoid EM-Calorimeter Dual Rad. RICH Aero RICH/DIRC/HR-ToF Tracking Micro-Vertex Tracking 30

31. 31

32. arXiv:1212.1701 http://www.bnl.gov/npp/docs/EIC_White_Paper_Final.pdf 32

33. Longitudinal Spin Structure 33

34. Transverse Momentum Dependence 34

35. Spatial Imaging DVCS 35

36. Saturation Scale Q S The ultra-relativistic boost amplifies the gluon densities in a nucleus 36

37. Diffractive Cross Section 37