1. Some Thoughts On a Possible Future Electron-Ion Collider T. Hallman Electron-Ion Collider User Group Meeting January 6-9, 2016 Berkeley, CA

2. EIC Meeting January 6-9, 2016 2 A Great Deal Has been Accomplished Over Quite A Long Time Physics at a High Energy Electron Ion Collider (09-43W) October 19 - 23, 2009 Exploring and understanding fully the role of gluons and sea quarks in the structure of the nucleon and atomic nuclei is a major frontier of nuclear and particle physics. Although there has been much progress thanks to data from HERA, a new dedicated facility will be essential for answering some of the most central questions. This facility is the Electron Ion Collider (EIC).…The present workshop primarily addresses the science at such a "stage-I" EIC… Report from the INT program "Gluons and the quark sea at high energies: distributions, polarization, tomography" September 13 to November 19, 2010 "Gluons and the quark sea at high energies: distributions, polarization, tomography" This INT program will address open questions about the dynamics of gluons and sea quarks in the nucleon and in nuclei. Answers to these questions are crucial for a deeper understanding of hadron and nuclear structure in QCD at high energies…These issues motivate arguments for a Electron Ion Collider (EIC) that will provide a precise imaging of gluons …

3. EIC Meeting January 6-9, 2016 3 Recent EIC Physics Workshops, Write Ups and Related Links National Academy of Science: Decadal plan for Nuclear Physics The Science of EIC: INT Program The INT Write Up: http://arxiv.org/abs/1108.1713http://arxiv.org/abs/1108.1713 Task force at Brookhaven National Laboratory Working Group at Jefferson Laboratory Numerous Talks at Conferences International Advisory Committee The members of the International Advisory Committee are: Jochen Bartels (DESY) Allen Caldwell (MPI, Munich) Albert De Roeck (CERN) Walter Henning (ANL, Chair) Dave Hertzog (UIUC) Xiangdong Ji (U. Maryland) Robert Klanner (U. Hamburg) Alfred Mueller (Columbia U.) Katsunobu Oide (KEK) Naohito Saito (KEK,J-PARC) Uli Wienands (SLAC) Additional Supporting Documents and Activities

4. EIC Meeting January 6-9, 2016 4 Looking Back Even Further (2010 Presentation by T. Ludlam)

5. EIC Meeting January 6-9, 2016 5 Getting Underway on R&D In a Coordinated Fashion

6. EIC Meeting January 6-9, 2016 6 Peer Review Mechanism for Guiding EIC R&D

7. EIC Meeting January 6-9, 2016 7 Looking Back Even Further 2002 NSAC LRP White Paper “…As discussed earlier, many open questions remain in the study of QCD at the high-energy frontier. Electron-nucleus collisions can provide complementary information to that obtained at RHIC. One of the technical options of the Electron-Ion Collider initiative would add this capability to the facility. This is an extremely exciting opportunity for the long term, since it allows access to a new regime within QCD and should shed light on the initial conditions for heavy-ion collisions at RHIC. As with RHIC II, R&D is essential in the near term so that a full scientific proposal can be developed.”” And other text therein…

8. EIC Meeting January 6-9, 2016 8 Proton (and nuclei) and black holes are the only fully relativistic (high enough energy density to excite the vacuum) stable bound systems in the universe. Protons can be studied in the laboratory. Protons are fundamental to the visible universe (including us) and their properties are dominated by emergent phenomena of the self-coupling strong force that generates high density gluon fields: o The mass of the proton (and the visible universe) o The spin of the proton o The dynamics of quarks and gluons in nucleons and nuclei o The formation of hadrons from quarks and gluons The study of the high density gluon field that is at the center of it all requires a high energy, high luminosity, polarized Electron Ion Collider The 2013 NSAC Subcommittee on Future Facilities identified the physics program for an Electron-Ion Collider as absolutely central to the nuclear science program of the next decade. The Long Term Future of QCD: Understanding the Glue That Binds Us All

9. EIC Meeting January 6-9, 2016 9 The New Long Range Plan: A Tool for Evidence-Based Planning NSAC partnership with the Division of Nuclear Physics of the APS to tap the full intellectual capital of the U.S. nuclear science community in identifying exciting, compelling science opportunities and a strategic plan for the next 5-10 years: Nuclear Structure & Nuclear Astrophysics meeting, Nuclear Structure Conveners: Mark Riley, Charlotte Elster; Nuclear Astrophysics Conveners: Hendrik Schatz and Michael Wiescher Venue: Mitchell Institute, Texas A&M University, Aug. 21-23, 2014 Meeting website: http://www.lecmeeting.org/http://www.lecmeeting.org/ Hadron and Heavy Ion QCD meeting, QCD Heavy Ion Conveners: Paul Sorensen and Ulrich Heinz, QCD Hadron Conveners: Haiyan Gao and Craig Roberts Venue: Temple University, Sept. 13-15, 2014 Website: https://phys.cst.temple.edu/qcdhttps://phys.cst.temple.edu/qcd Fundamental symmetries, Neutrinos, Neutrons, and the relevant Nuclear Astrophysics, Conveners: Hamish Robertson, Michael Ramsey- Musolf Dates: Sept. 28-29, 2014 Venue: Crowne Plaza, O'Hare Airport Website: http://fsnutown.phy.ornl.gov/fsnuweb/index.htmlhttp://fsnutown.phy.ornl.gov/fsnuweb/index.html Nuclear Theory Computing: High performance computing (Computation in nuclear physics), Washington DC, July 14-15, 2014 High performance computing Education [NSF scope - Workforce Training in DOE] and Innovation... across all areas of nuclear physics Conveners: Michael Thoennessen, Graham Peaslee Venue: NSCL, Michigan State University, Aug. 6-8, 2014; Website: http://meetings.nscl.msu.edu/Education-Innovation-2014http://meetings.nscl.msu.edu/Education-Innovation-2014 Resolution Meeting: Spring of 2015 Long Range Plan: October 2015

10. EIC Meeting January 6-9, 2016 10 2015 Long Range Plan for Nuclear Science RECOMMENDATION I The progress achieved under the guidance of the 2007 Long Range Plan has reinforced U.S. world leadership in nuclear science. The highest priority in this 2015 Plan is to capitalize on the investments made.  With the imminent completion of the CEBAF 12-GeV Upgrade, its forefront program of using electrons to unfold the quark and gluon structure of hadrons and nuclei and to probe the Standard Model must be realized.  Expeditiously completing the Facility for Rare Isotope Beams (FRIB) construction is essential. Initiating its scientific program will revolutionize our understanding of nuclei and their role in the cosmos  The targeted program of fundamental symmetries and neutrino research that opens new doors to physics beyond the Standard Model must be sustained  The upgraded RHIC facility provides unique capabilities that must be utilized to explore the properties and phases of quark and gluon matter in the high temperatures of the early universe and to explore the spin structure of the proton.

11. EIC Meeting January 6-9, 2016 11 2015 Long Range Plan for Nuclear Science RECOMMENDATION II The excess of matter over antimatter in the universe is one of the most compelling mysteries in all of science. The observation of neutrinoless double beta decay in nuclei would immediately demonstrate that neutrinos are their own antiparticles and would have profound implications for our understanding of the matter- antimatter mystery. We recommend the timely development and deployment of a U.S.- led ton-scale neutrinoless double beta decay experiment.

12. EIC Meeting January 6-9, 2016 12 2015 Long Range Plan for Nuclear Science RECOMMENDATION III Gluons, the carriers of the strong force, bind the quarks together inside nucleons and nuclei and generate nearly all of the visible mass in the universe. Despite their importance, fundamental questions remain about the role of gluons in nucleons and nuclei. These questions can only be answered with a powerful new electron ion collider (EIC), providing unprecedented precision and versatility. The realization of this instrument is enabled by recent advances in accelerator technology. We recommend a high-energy high-luminosity polarized EIC as the highest priority for new facility construction following the completion of FRIB.

13. EIC Meeting January 6-9, 2016 13 RECOMMENDATION IV We recommend increasing investment in small-scale and mid-scale projects and initiatives that enable forefront research at universities and laboratories. Innovative research and initiatives in instrumentation, computation, and theory play a major role in U.S. leadership in nuclear science and are crucial to capitalize on recent investments. The NSF competitive instrumentation funding mechanisms, such as the Major Research Instrumentation (MRI) program and the Mathematical & Physical Sciences mid- scale research initiative, are essential to enable university researchers to respond nimbly to opportunities for scientific discovery. Similarly, DOE-supported research and development (R&D) and Major Items of Equipment (MIE) at universities and national laboratories are vital to maximize the potential for discovery as opportunities emerge. These NSF funding mechanisms are an essential component to ensure that NSF-supported scientists have the resources to lead significant initiatives. These programs are competitive across all fields, and an increase in the funds available in these funding mechanisms would benefit all of science, not just nuclear physics. With both funding agencies, small- and mid-scale projects are important elements in increasing the agility of the field to react to new ideas and technological advances. 2015 Long Range Plan for Nuclear Science

14. EIC Meeting January 6-9, 2016 14 The Facility for Rare Isotope Beams is  50% Complete FRIB – September 16, 2015 (TPC: $635.5M DOE + $94.5M MSU) Project Completion: 3Q FY 2022 FRIB – September 16, 2015 (TPC: $635.5M DOE + $94.5M MSU) Project Completion: 3Q FY 2022 FRIBPYsFY13FY14FY15FY16FY17FY18FY19FY20FY21TOTAL DOE TPC $000s51,00022,00055,00090,000100,000 97,20075,00040,0005,300635,500

15. EIC Meeting January 6-9, 2016 15 It is Good to Push, But Hazardous to Make Projections

16. EIC Meeting January 6-9, 2016 16 What Aspect Are We Working On Now? We continue to work on whether the number of future electron ion colliders will be 1 or 0. (The first possibility is of course highly anticipated based on QCD science and future mission need for the field)

17. EIC Meeting January 6-9, 2016 17 Next Formal Step on the Science Case THE NATIONAL ACADEMIES OF SCIENCES, ENGINEERING, AND MEDICINE Division on Engineering and Physical Science Board on Physics and Astronomy U.S.-Based Electron Ion Collider Science Assessment Summary The National Academies of Sciences, Engineering, and Medicine (“National Academies”) will form a committee to carry out a thorough, independent assessment of the scientific justification for a U.S. domestic electron ion collider facility. In preparing its report, the committee will address the role that such a facility would play in the future of nuclear science, considering the field broadly, but placing emphasis on its potential scientific impact on quantum chromodynamics. The need for such an accelerator will be addressed in the context of international efforts in this area. Support for the 18-month project in the amount of $540,000 is requested from the Department of Energy. Proposal being considered by NAS Board this week. Funding planned in NP Budget

18. EIC Meeting January 6-9, 2016 18 The Other Front: Technical Risk Temple LRP EIC Costing Exercise ‘Understanding that a detailed conceptual design has not been completed, the Sub- committee is asked to provide NSAC with its best current estimate of costs of the projects that will address the physics opportunities identified in the EIC White Paper (arXiv: 1212.1701v2), including R&D, construction, pre-operating and operating costs and initial experimental equipment. NSAC is aware that there are uncertainties regarding siting and other issues that limit the precision of such an estimate at this time. Nevertheless, the advice of the Sub-committee will be of great value to NSAC as it evaluates the relative merit of this and other initiatives.” The subcommittee members were C. Adolphsen, G. Bock, K. Boudwin, T. Glasmacher, S. Holmes, M. Klein, R. Laxdal, D. Leitner, J. Seeman, E. Temple chair, and D. Geesaman ex-officio. (Appendix 2) The two proposals largely address the energy and luminosity requirements of the Electron- Ion Collider White Paper. While eRHIC exceeds the white paper goal of 100 GeV/u for all ion species with a maximum e-p center of mass energy of 145 GeV, the MEIC will achieve a maximum e-p center-of-mass energy of 63 GeV and center-of-mass energies of 40 GeV/u for the heaviest ion beams. Both designs achieve maximum luminosities that exceed the EIC white paper goals.

19. EIC Meeting January 6-9, 2016 19 Temple LRP Costing Exercise The presented cost estimates, in FY15$, ranged for the Total Project Costs (without detector) of TPC(eRHIC) = $756M to TPC(MEIC) = $1,290M to Total Project Cost (with detector) of TPC(eRHIC) = $986M to TPC(MEIC) = $1,480M. The estimates of the annual operating costs were presented as eRHIC = $173M and MEIC = $117M. eRHIC incorporates certain technical advances which are beyond the state of the art. The proposed 31% contingency is, in the opinion of the subcommittee, insufficient. MEIC is based on largely conventional technology with fewer technical risks. The proposed 35% contingency is marginally sufficient. Other Project Costs (Research and Development [R&D], Pre-operations, conceptual design and environmental studies) were not estimated as carefully or at all. Both R&D and Pre-operations for both proposals are thought to be underestimated. Of the uncertainties that remain, the subcommittee considers the dominant ones to be technical. Given these technical uncertainties, based on the plans presented by both teams, the subcommittee concluded that an EIC could be built for about $1.5B in FY15$. We note that critical information on the performance of the eRHIC energy recovery linac (ERL) and the coherent electron cooling (CeC) approaches is planned to become available in 2016. Such information could go a long way toward reducing the greatest technical uncertainties for the eRHIC concept. The total on-project cost for both approaches may potentially be reduced as technical risk is retired, by off-project funds especially for the detectors from international sources, by redirection of operating funds at the host laboratory or by reducing the design requirements.

20. EIC Meeting January 6-9, 2016 20 Outlook Our work continues… Independent Vetting of Science Case R&D & Design Refinement to Reduce Risk and $$ Decision on when to go for CD0, Mission Need Mechanism for determining “Best Value” to the United States