1 QCD at high T Future Opportunities in QCD SURA, December 15-16, 2006 The future is not what it used to be. Yogi Berra

2 Paths of Discovery RHIC (I) was built to discover a new phase of strongly interacting matter. It has done so, and in so doing, it has opened up many new questions, which could not be posed before the RHIC physics program started. It has also left many questions asked before RHIC started unanswered. There remains a lot to be done to answer the old questions on which the original RHIC physics program was justified. There is also the need to explore the new questions raised by the RHIC data and to study matter in the energy regime beyond RHIC. Columbus  Cortez  Lewis & Clark

3 1. Deconfinement and chiral symmetry restoration What is the physics of the QCD phase transformation? 2. Entropy Generation How and why does it thermalize so fast? 3. State of Matter What really is an ideal relativistic quantum fluid? 4. Degrees of freedom Is it a s-QGP or something else? 5. Phase Transitions Is there a critical point and can RHIC see it? Fundamental Physics Questions

4 Probes Probes of “soft”, collective physics”  Flow properties – shear viscosity  Which quasiparticles carry flow?  Do energetic partons induce a sonic boom?  Probes of the QCD critical point  Real world application of string theory? Hard & penetrating probes  Relation between phenomenology and matter properties  Energy loss = seeing the glue!  Color screening

5 Questions Do we know what the right questions are? Do we know how to address the questions experimentally? Do we have the right facilities to do the experiments that need to be done? Are there questions that require new facilities?

6 Final question Why should someone interested in hadronic structure or hadron spectroscopy care about QCD at high T (or baryon density)? And vice versa.