The Long Range Plan for QCD

1. The Long Range Plan for QCD Peter Jacobs, LBNL

2. DOE/NSF Charge to NSAC The Long Range Plan for QCD

3. a.k.a. American Competitiveness Initiative (2006 State of the Union Address) DOE/NSF Charge to NSAC cont’d The Long Range Plan for QCD

4. NSAC charge to DNP: Town Meetings The Long Range Plan for QCD

5. QCD and Hadron Physics • S. Capstick L. Cardman, A.Deshpande, X. Ji, C.Keppel, C. Meyer, Z. Meziani, J. Negele, • J.-C. Peng • Phases of QCD MatterP. Jacobs, D. Kharzeev, B. Mueller, J. Nagle, • K. Rajagopal, S. Vigdor The Long Range Plan for QCD

6. Background White Papers Posted at: http://www.physics.rutgers.edu/np/2007lrp-home.html • RHIC II • Electron Ion Collider • RHIC Theory Upgrade • LHC: • ATLAS Heavy Ions • CMS Heavy Ions • ALICE-US • LHeC (new proposal for electron ring in LHC tunnel) • Accelerator R&D The Long Range Plan for QCD

7. Summary of RHIC thus far W. Zajc The hottest (T~200-400 MeV) densest (jet quenching: ei~30-60e0) Matter (thermal yields) ever studied in the laboratory Flows (large elliptic flow) as a (nearly) perfect fluid with systematic patterns consistent with quark degrees of freedom (valence quark scaling) and a viscosity to entropy-density ratio lower (?) than any other known fluid, with a value near (?) a conjectured quantum bound (h/s~2-3 x 1/4p) The Long Range Plan for QCD

8. So are we done? U. Heinz The Long Range Plan for QCD

9. U. Heinz The Long Range Plan for QCD

10. AdS/CFT: a startling development from string theory Zajc, Kaplan Conjecture: hidden within every non-Abelian gauge theory, even within the weak and strong nuclear interactions, is a theory of quantum gravity. (Horowitz and Polchinski, gr-qc/0602037 ) Has stimulated new directions in theory (e.g. lower bound on h/s arises from basic quantum mechanics but was first derived in string theory) Potential connections to RHIC/LHC heavy ion physics: shear viscosity, jet quenching, J/ suppression,… But speculative at present: no testable calculations or predictions yet The Long Range Plan for QCD

11. Together, RHIC and LHC span an energy range of more than 3 units of magnitude (say 50 GeV - 5.5 TeV). • How do the properties of hot and dense QCD matter evolve with energy from RHIC to LHC? Don’t trust the argument, that the high-temperature phase of QCD is featureless above Tc. This may be true for the energy density, but: • Measurable quantities related to 1st principle calculations, such as • are likely to satisfy non-linear small-x evolution equations (similar to Qs) • QCD measures of deviations from conformality • change strongly from Tc to 3Tc. This may provide • crucial input for fundamental theoretical approaches • (e.g. string theory), which start from perturbations of a conformal framework I advocate to identify this question now as a major scientific challenge of the next decade, to be explored in an interplay of RHIC and LHC. Consequence: RHIC luminosity upgrade also motivated by increasing kinematical reach for comparison with LHC. The interplay of RHIC and LHC U. Wiedemann The Long Range Plan for QCD

12. Big Questions for an e+p/A colliderVogelsang, Ent, Kovchegov, Surrow,… EIC: polarized e+p, unpolarized e+A Broad theme: precision studies of emergent features of QCD What are the momentum distributions of quarks, anti-quarks and gluons in the nucleon? What symmetries (flavor, isospin) hold or are broken in the nucleon? How are quarks and gluons distributed spatially in the nucleon? What is the nature of glue at high density? • How do strong fields appear in hadronic or nuclear wave functions at high energies? • What are the appropriate degrees of freedom? • How do they respond to external probes or scattering? • Is this response universal (ep, pp, eA, pA, AA)? The Long Range Plan for QCD

13. Proposed EIC Designs L. Merminga LHeC L = 1.1x1033 cm-2s-1 Ecm = 1.4 TeV eRHIC L = 2.6x1033 cm-2s-1 Ecm = 140 GeV ELIC (JLab) L = 7.7x1034 cm-2s-1 Ecm = 65 GeV L = 0.47x1033 cm-2s-1 Ecm = 100 GeV Luminosities are for e-p collisions The Long Range Plan for QCD

14. Summary of EIC candidates L. Merminga *Requires second ring **one IR The Long Range Plan for QCD

15. F2 will be one of the first measurements at EIC nDS, EKS, FGS: pQCD models with different amounts of shadowing Physics reach of eRHIC: F2(x,Q2)sea quarks generated by glue Th. Ullrich EIC will distinguish between pQCD and saturation modelpredictions The Long Range Plan for QCD

16. FL at eRHIC: direct measurement of glue Th. Ullrich EIC: (10+100) GeV Ldt = 2/A fb-1 Q2/xs = y Needs s scan EIC will measure G(x,Q2) precisely The Long Range Plan for QCD

17. Phases of QCD: Recommendation #1 • 1. Our central goal is a dramatic advance in our understanding of QCD Matter, through quantitative comparison of theory and experiment to determine the properties of the strongly interacting Quark-Gluon Plasma discovered in the initial phase of RHIC operations, and through further exploration of the QCD phase diagram at non-zero baryon density where a critical point has been predicted. The essential requirements for the success of this scientific program are therefore our highest priorities: • Effective utilization of the RHIC facility and completion of the ongoing detector upgrade program; • The RHIC II luminosity upgrade, which will enable quantitative study of rare processes; • Strong support for the ongoing theoretical studies of QCD matter, including finite temperature and finite baryon density lattice QCD studies and phenomenological modeling, and an increase of funding to support new initiatives enabled by experimental and theoretical breakthroughs. The Long Range Plan for QCD

18. Phases of QCD Recommendation #2: LHC 2. We strongly recommend significant and timely participation of U.S. groups in the LHC heavy ion program, which will study QCD matter at the highest energy densities and temperatures available in the laboratory. This program will test and extend the insights reached in the RHIC program, and has the potential to make important new discoveries about QCD Matter. The Long Range Plan for QCD

19. Phases of QCD Recommendation #3: EIC • Same EIC bullet will appear in “Phases of QCD Matter” and “Hadronic Physics” Summary White Papers (minor modifications not yet finalized) • 3. An Electron-Ion Collider (EIC) facility is the highest priority of the QCD community for new construction after the JLab 12 GeV and the RHIC II luminosity upgrades. EIC will address compelling physics questions essential for understanding the fundamental structure of matter: • Precision imaging of sea-quarks and gluons to determine the full spin, flavor and spatial structure of the nucleon; • Definitive study of the universal nature of strong gluon fields manifest in nuclei. • This goal requires that R&D resources be allocated for expeditious development of collider and experimental design. The Long Range Plan for QCD

20. Further recommendations Still to be written: 4. Common theory bullet (the bullet is common, not the theory) 5. Education and Outreach 6. Accelerator R&D The Long Range Plan for QCD

21. What happens next? • Summary White Paper from each Town Meeting, • presents and justifies priorities (bullets) • first draft in early March • Status reports and discussion at NSAC meeting March 8-9 • Status reports at Spring APS Meeting, Jacksonville, April 14-17 (session U2, Monday p.m.) • The smoke-filled room: Long Range Plan “Resolution Meeting”, Galveston TX, April 30-May 4 The Long Range Plan for QCD