1. The Electron Ion Collider Project: April 12, 2011 DIS2011, Newport News, VA Abhay Deshpande

2. Related Talks: 4/12/2011 Abhay Deshpande Overview of the US EIC Project 2 An update on eRHIC acceleraor V. Litvinenko Design status of of MEIC at JLab V. Morozov PDFs today and tomorrow M. Stratmann Theory overview of e-A physics at the EIC J. Jalilian-Marian Experimental overview of e-A physics at the EIC T. Ullrich A new Monte Carlo event generator for eA collisions at low-x T. Toll Theory overview of e+p physics at an EIC J. Qiu Experimental overview of e+p physics at an EIC H. Gao Imaging sea quarks and gluons at the EIC T. Horn Ep physics opportunities at eRHIC T. Burton Transverse single-spin asymmetry measurement from SIDIS at an EIC M. Huang Weak mixing angle measurement at EIC Y. Li PHENIX and STAR Detector Upgrades (for use as Stage 1 eRHIC detector) E. O’Brien, J. Dunlop … And of course, low-x physics at LHeC is a physics connection

3. Success of pQCD at High Q: Jet Cross section Input: – F 2 (x,Q 2 ) structure function from HERA – Next to Leading Order perturbative QCD 4/12/2011 Abhay Deshpande Overview of the US EIC Project 3 Compilation: J. Putschke

4. QCD definitely correct, but… Lattice QCD Starting from QCD lagrangian  Static properties of hadrons: hadron mass spectrum 4/12/2011 Abhay Deshpande Overview of the US EIC Project 4 Calculations possible in perturbation theory assuming coupling is small, at high Q Problematic at low Q  fast rise of  S (Q) No guidance on partonic dynamics

5. Do we really “understand” QCD? While there is no reason to doubt QCD, our level of understanding of QCD remains extremely unsatisfactory: both at low & high energy Can we explain basic properties of hadrons such as mass and spin from the QCD degrees of freedom at low energy? What are the effective degrees of freedom at high energy? How do these degrees of freedom interact with each other and with other hard probes? What can we learn from them about confinement & universal features of the theory of QCD? After ~20+ yrs of experimental & theoretical progress, we are only beginning to understand the many body dynamics of QCD 4/12/2011 Abhay Deshpande Overview of the US EIC Project 5

6. Generation of Mass – Gluons in QCD Protons and neutrons form most of the mass of the visible universe 99% of the nucleon mass is due to self generated gluon fields gluon dynamics identical – Similarity between p, n mass indicates that gluon dynamics is identical & overwhelmingly important Lattice QCD supports this 4/12/2011 Abhay Deshpande Overview of the US EIC Project 6 Higgs Mechanism, often credited with mass generation, is of no consequence Bhagwat et al.

7. HOW WELL DO WE UNDERSTAND GLUONS? What is the role of gluons at high energy? 4/12/2011 Abhay Deshpande Overview of the US EIC Project 7

8. Gluon distribution at low-x understood? Indefinite rise Indefinite rise artifact linear – Could this be an artifact of using of linear DGLAP in gluon extraction? – Infinite high energy hadron cross section? How would we find out? How would we find out? – Need theory development – Need experimental measurements at lower x! 4/12/2011 Abhay Deshpande Overview of the US EIC Project 8 No higher energy e-p collider than HERA!  other than “LHeC” OR  Use Nuclei: naturally enhance the densities of partonic matter Why not use Nuclear DIS at highest available energy? No higher energy e-p collider than HERA!  other than “LHeC” OR  Use Nuclei: naturally enhance the densities of partonic matter Why not use Nuclear DIS at highest available energy?

9. Low-x, higher twist & Color Glass Condensate 4/12/2011 Abhay Deshpande Overview of the US EIC Project 9 McLerran, Venugopalan… See Review: F. Gelis et al.,, arXiv:1002.0333) non-linear Small coupling, high gluon densities  Saturation Scale Q S (x,Q 2,A) Method of including non-linear effects in DGLAP equation  Small coupling, high gluon densities  Saturation Scale Q S (x,Q 2,A)  Some form of saturation, including Color Glass Condensate No unambiguous experimental evidence yet, but many smoking guns (HERA, RHIC & now LHC!) Could be explored cleanly in future with a high energy electron-Nucleus Collider Could be explored cleanly in future with a high energy electron-Nucleus Collider Kowalski Teany PRD 68:11400 5 Kowalski Teany PRD 68:11400 5

10. UNDERSTANDING NUCLEON SPIN: WHAT ROLE DO GLUONS PLAY? 4/12/2011 Abhay Deshpande Overview of the US EIC Project 10

11. Evolution: Our Understanding of Nucleon Spin ? 1980s 1990/2000s We have come a long way, but do we understand nucleon spin? 4/12/2011 11 Abhay Deshpande Overview of the US EIC Project

12. Status of “Nucleon Spin Crisis Puzzle” know We know how to determine  and  g precisely: data+pQCD – ½ (  ) ~ 0.15 : From fixed target pol. DIS experiments not large as anticipated in the 1990s, but measurements & precision needed at low & high x – RHIC-Spin:  g not large as anticipated in the 1990s, but measurements & precision needed at low & high x 4/12/2011 Abhay Deshpande Overview of the US EIC Project 12 PHENIX

13.  g(x) @ Q 2 =10 GeV 2 Global analysis: DIS, SIDIS, RHIC-Spin Uncertainly on  G large at low x 4/12/2011 Abhay Deshpande Overview of the US EIC Project 13 de Florian, Sassot, Stratmann & Vogelsang Present positive  g Low x measurements =Opportunity! Low x measurements =Opportunity!

14. Status of “Nucleon Spin Crisis Puzzle” know We know how to measure  and  G precisely using pQCD – ½ (  ) ~ 0.15 : From fixed target pol. DIS experiments not large as anticipated in the 1990s, but measurements & precision needed at low & high x – RHIC-Spin:  G not large as anticipated in the 1990s, but measurements & precision needed at low & high x Orbital angular momenta: Generalized Parton Distributions (GPDs): H,E,E’,H’ – Quark GPDs: 12GeV@JLab & COMPASS@CERN – Gluons @ low x  J G  will need the future EIC! Would it not be great to have a (2+1)D tomographic image of the proton…. (2: x,y position and +1:momentum in z direction)? Would it not be great to have a (2+1)D tomographic image of the proton…. (2: x,y position and +1:momentum in z direction)? – Transverse Momentum Distributions, GPDs of Quarks & Gluons… full understanding of transverse and longitudinal hadron structure including spin! 4/12/2011 Abhay Deshpande Overview of the US EIC Project 14

15. The Proposal: Future DIS experiment at an Electron Ion Collider : A high energy, high luminosity (polarized) ep and eA collider and a suitably designed detector [2] [3] [1] Measurements: [1]  Inclusive [1] and [2] or [3]  Semi-Inclusive [1] and [2] and [3]  Exclusive Inclusive  Exclusive Low  High Luminosity Demanding Detector capabilities

16. EIC : Basic Parameters 10 5 E e =10 GeV (5-30 GeV variable) 250 50 E p =250 GeV (50-325 GeV Variable) Sqrt(S ep ) = 100 (30-200) GeV Sqrt(S ep ) = 100 (30-200) GeV X min = 10 -4 ; Q 2 max = 10 4 GeV Beam polarization ~ 70% for e,p Luminosity L ep = 10 33-34 cm -2 s -1 Luminosity L ep = 10 33-34 cm -2 s -1 Minimum Integrated luminosity: Minimum Integrated luminosity: – 50 fb -1 in 10 yrs (100 x HERA) – Possible with 10 33 cm -2 s -1 – Recent projections much higher Nuclei: 100 (140) p->U; E A =20-100 (140) GeV/N 63 (75) Sqrt(S eA ) = 12-63 (75) GeV L eA /N = 10 33 cm -2 s -1 4/12/2011 Abhay Deshpande Overview of the US EIC Project 16

17. Machine Designs Details in Talks by V. Litvinenko & V. Morozov eRHIC at Brookhaven National Laboratory using the existing RHIC complex ELIC at Jefferson Laboratory using the Upgraded 12GeV CEBAF Both planned to be STAGED

18. MEIC : Medium Energy EIC Three compact rings: 3 to 11 GeV electron Up to 12 GeV/c proton (warm) Up to 60 GeV/c proton (cold) low-energy IP polarimetry medium-energy IPs 4/12/2011 Abhay Deshpande Overview of the US EIC Project 18 Exists

19. ELIC: High Energy & Staging StageMax. Energy (GeV/c) Ring Size (m) Ring TypeIP # pepe Medium96111000ColdWarm3 High250202500ColdWarm4 Serves as a large booster to the full energy collider ring Arc Straight section 4/12/2011 Abhay Deshpande Overview of the US EIC Project 19

20. V.N. Litvinenko eSTAR ePHENIX Coherent e-cooler Beam dump Polarized e-gun New detector 0.6 GeV 30 GeV 27.55 GeV 22.65 GeV 17.75 GeV 12.85 GeV 3.05 GeV 7.95 GeV Linac 2.45 GeV Linac 2.45 GeV 100 m 25.1 GeV 20.2 GeV 15.3 GeV 10.4 GeV 30.0 GeV 5.50 GeV 27.55 GeV eRHIC: polarized electrons with E e ≤ 30 GeV will collide with either polarized protons with E e ≤ 325 GeV or heavy ions E A ≤ 130 GeV/u eRHIC staging: All energies scale proportionally Small gap magnets 5 mm gap 0.3 T @ 30 GeV 4/12/2011 Abhay Deshpande Overview of the US EIC Project 20

21. 4/12/2011 Abhay Deshpande Overview of the US EIC Project 21

22. nucleuselectron proton nucleus eSTAR See J. Dunlop’s talk ePHENIX See E. O’Brien’s talk 4/10/11 Abhay Deshpande on EIC Collaboration's Perspective 22

23. Emerging eRHIC Detector Concept 4/12/2011 Abhay Deshpande Overview of the US EIC Project high acceptance -5 <  < 5 central detector good PID and vertex resolution (< 5  m) tracking and calorimeter coverage the same  good momentum resolution, lepton PID low material density  minimal multiple scattering and brems-strahlung very forward electron and proton detection  maybe dipole spectrometers Forward / Backward Spectrometers: E. Aschenauer et al. BNL EIC Task Force & EIC Collaboration

24. eRHIC IRs, β *=5cm, l*=4.5 m Up to 30 GeV e - beam 325 GeV p beam Spin-Rotator 10 mrad, with crab crossing L=1.4x10 34 cm -2 s -1, 200 T/m gradient 0.45 m Nb 3 Sn 200 T/m Star detector ©Dejan Trbojevic 90.m 325 GeV p beam Exploit LARP development of Nb 3 Sn SC quads with 200 T/m gradient Integrated with “new” detector design. Field-free electron pass thru hadron triplet magnets  minimal SR background. IR combined function magnet design See talk by Litvinenko’s

25. solenoid electron FFQs 50 mrad 0 mrad ion dipole w/ detectors ions electrons IP ion FFQs 2+3 m 2 m Detect particles with angles below 0.5 o beyond ion FFQs and in arcs. detectors Detect particles with angles down to 0.5 o before ion FFQs. Need 1-2 Tm dipole. Central detector EM Calorimeter Hadron Calorimeter Muon Detector EM Calorimeter Solenoid yoke + Muon Detector TOF HTCC RICH RICH or DIRC/LTCC Tracking 2m 3m 2m 4-5m Solenoid yoke + Hadronic Calorimeter Very-forward detector Large dipole bend @ 20 meter from IP (to correct the 50 mr ion horizontal crossing angle) allows for very-small angle detection (<0.3 o ) Detector & IR Design: ELIC Nadel-Turonski, Horn, Ent And EIC Collaboration 4/12/2011 Abhay Deshpande Overview of the US EIC Project 25

26. Impact of EIC…. “golden measurements” Science of EIC: Institute of Nuclear Theory (INT) Program at U. of Washington: Sep-Nov 2010 Organizers: D. Boer, M. Diehl, R. Milner, R. Venugopalan, W. Vogelsang See the INT workshop for details of all studies http://www.int.washington.edu/INT_03/ Details in the EIC talks in this conference…. 4/12/2011 Abhay Deshpande Overview of the US EIC Project 26

27. Summary: Science of EIC: Precise Investigations of the “Glue” 4/12/2011 Abhay Deshpande Overview of the US EIC Project 27

28. Spin program at the EIC: 4/12/2011 Abhay Deshpande Overview of the US EIC Project 28 Science Deliverable Basic Measurement Uniqueness Feasibility Relevance Requirements spin structure at small x contribution of Δ g, ΔΣ to spin sum rule inclusive DIS ✔ need to reach x=10 - 4 large x,Q 2 coverage about 10fb -1 full flavor separation in large x,Q 2 range strangeness, s(x)-s(x) polarized sea semi-inclusive DIS ✔ very similar to DIS excellent particle ID improved FFs (Belle,LHC,…) electroweak probes of proton structure flavor separation electroweak parameters inclusive DIS at high Q 2 ✔ some unp. results from HERA 20x250 to 30x325 positron beam ? polarized 3 He beam ?

29. Nucleon Spin: Precision measurement of  G 4/12/2011 Abhay Deshpande Overview of the US EIC Project 29 Yellow band (left) reduces to the band shown with red dashed line (right) Yellow band (left) reduces to the band shown with red dashed line (right) Sassot & Stratmann

30. 4/12/2011 Abhay Deshpande Overview of the US EIC Project 30 See more in talks by: T. Ullrich, J. Jalilian-Marian

31. GPDs and transverse parton imaging 4/12/2011 Abhay Deshpande Overview of the US EIC Project 31 x < 0.1x ~ 0.3x ~ 0.8 Fourier transform in momentum transfer x ~ 0.001 EIC: 1) x < 0.1: gluons 1) x < 0.1: gluons! 2)  ~ 0  the “take out” and “put back” gluons act coherently. 2)  ~ 0 x -  x +   d

32. Diffractive vector meson production in eA 4/12/2011 Abhay Deshpande Overview of the US EIC Project 32  d See T. Ullrich’s talk on eA physics at the EIC Precise transverse imaging of the gluons proton-heavy nuclei Later, how low x dynamics modifies this transverse gluon distribution Exclusive coherent (at small t) and incoherent (intermediate t) Diffraction Experimental challenges being Studued.

33. EIC Project status and plans A “collaboration” of highly motivated people intends to take this project to realization: – EIC Collaboration Web Page: http://web.mit.edu/eicc/http://web.mit.edu/eicc/ BNL: https://wiki.bnl.gov/eic/index.php/Main_Page JLab: http://www.jlab.org/meic – 100+ dedicated physicists from 20+ institutes – Details of many recent studies: Recent Workshop @ INT at U. of Washington : http://www.int.washington.edu/program/INT_03 http://www.int.washington.edu/program/INT_03 – Task Force at BNL (E. Aschenaur, T. Ullrich) and at Jefferson Laboratory (R. Ent) – Steering Committee (contact: AD and R. Milner) International Advisory Committee formed by the BNL & Jlab Management to steer this project to realization: W. Henning (ANL, Chair ), J. Bartels (DESY),A. Caldwell (MPI, Munich) A. De Roeck (CERN), R. Gerig (ANL), D. Hetrzog (U of W), X. Ji (Maryland), R. Klanner (Hamburg), A. Mueller (Columbia), S. Nagaitsev (FNAL), N. Saito (J-PARC), Robert Tribble (Texas A&M), U. Wienands (SLAC), V. Shiltev (FNAL) Plan to go to the NSAC Long Range Plan (2012/13) with the science case & machine/detector designs (including costs & realization plans) Plan to go to the NSAC Long Range Plan (2012/13) with the science case & machine/detector designs (including costs & realization plans) 4/12/2011 Abhay Deshpande Overview of the US EIC Project 33

34. Generic Detector R&D for an EIC Community wide call for R&D Detector proposals for EIC Program run from BNL (RHIC R&D funds), NOT site specific Very Recent: Deadline April 4 th, 2011 (more opportunities in future) New detector technology for fiber sampling calorimetry for EIC and STAR. UCLA, Texas A&M, Penn State Front end readout modules for data acquisition and trigger system. Jefferson Lab DIRC based PID for EIC Central Detector. Catholic U. of America, Old Dominion U., JLab, GSI (Darmstadt) Liquid scintillator calorimeter for the EIC. Ohio State U. Test of improved radiation tolerant silicon PMTs. Jefferson Lab Letter of Intent for detector R&D towards an EIC detector (Low mass tracking and PID ). BNL, Florida Inst. Tech., Iowa State, LBNL, LANL, MIT, RBRC, Stony Brook, U. of Virginia, Yale U. Exploring possible new technologies & attracting new collaborators…. 4/10/11 Abhay Deshpande on EIC Collaboration's Perspective 34

35. Luminosity upgrade: Further luminosity upgrades (pp, low-E) Staged approach to eRHIC LHC HI starts RHIC-II science by- passing RHIC-II project Opportunity for up- grade* or 1 st EIC stage (eRHIC-I) EIC = Electron- Ion Collider; eRHIC = BNL realization by adding e beam to RHIC Further luminosity upgrades (pp, low-E) eRHIC-I physics * New PHENIX and STAR Decadal Plans provide options for this period. Dedicated storage ring for novel charged-particle EDM measurements another option. © V. Litvinenko eRHIC will add electron ERL inside RHIC tunnel, going from 5 to 30 GeV in stages electron recirc- ulation mag- nets S. Vigdor, BNL Associate Director 35

36. 4/12/2011 Abhay Deshpande Overview of the US EIC Project 36 EIC at JLab Realization Imagined Activity Name 2010201120122013201420152016201720182019202020212022202320242025 12 Gev Upgrade FRIB EIC Physics Case NSAC LRP CD0 Machine Design/R&D CD1/D’nselect CD2/CD3 Construction H. Montgomery, Jeff. Laboratory Director

37. Summary Science Case for EIC:  “Precision study of the role of gluons & sea quarks in QCD” Many body dynamics in QCD is an essential focus of this study. Possibilities of precision EW & other physics being explored. The EIC Collaboration & the BNL+Jlab managements are moving ( together ) towards realization: NSAC approval 2013  Next Milestone Machine R&D, detector discussions, simulation studies towards making the final case including detailed detector design and cost considerations needs to occur within the next two years… INVITATION: Ample opportunities to get involved and influence the design of this machine according to your own physics interests and be participate in the exploration of the “next QCD frontier…”! 4/12/2011 Abhay Deshpande Overview of the US EIC Project 37

38. Related detailed talks: Reminder… 4/12/2011 Abhay Deshpande Overview of the US EIC Project 38 An update on eRHIC acceleraor V. Litvinenko Design status of of MEIC at JLab V. Morozov PDFs today and tomorrow M. Stratmann Theory overview of e-A physics at the EIC J. Jalilian-Marian Experimental overview of e-A physics at the EIC T. Ullrich A new Monte Carlo event generator for eA collisions at low-x T. Toll Theory overview of e+p physics at an EIC J. Qiu Experimental overview of e+p physics at an EIC H. Gao Imaging sea quarks and gluons at the EIC T. Horn Ep physics opportunities at eRHIC T. Burton Transverse single-spin asymmetry measurement from SIDIS at an EIC M. Huang Weak mixing angle measurement at EIC Y. Li PHENIX and STAR Detector Upgrades (for use as Stage 1 eRHIC detector) E. O’Brien, J. Dunlop … And of course, low-x physics at LHeC is a physics connection

40. EIC: the Machines, IR and Detector Both BNL and JLab machine designs have progressed significantly. In spite of very different starting points for collider concepts: Both designs are now converging to similar luminosities: – Few x 10 34 cm -2 sec -1 for high energy – 10 33-34 cm -2 sec -1 for low energy Both plan a staged realization Both designs have settled on more than one IR point Both machine designs integrate detector design in to the machine lattice Both detectors concepts include a central solenoid and forward dipole, extensive low mass tracking for low x and good particle ID 4/10/11 Abhay Deshpande on EIC Collaboration's Perspective 40

41. Measurement of Glue at HERA Scaling violations of F 2 (x,Q 2 ) linear NLO pQCD analyses: fits with linear DGLAP* equations 4/12/2011 Abhay Deshpande Overview of the US EIC Project 41 Gluon dominates * Dokshitzer, Gribov, Lipatov, Altarelli, Parisi

42. EIC Detector will aim to catch: Wide range in x-Q 2 extremely important to understand longitudinal & transverse spin/momentum distributions and dynamics – Not available at any other existing or future facility with polarized hadron beams being considered… – Lessons learnt from HERA (about measurements at low-x) 4/12/2011 Abhay Deshpande Overview of the US EIC Project 42