1. Heavy Ions at RHIC RHIC-II and beyond Thomas Ullrich (BNL) QCD at High-T Session QCD Workshop, Washington DC, December 15-16, 2006 1.RHIC program: understanding what we see - a long way to go 2.Questions raised at RHIC that we won’t be able to answer with pp, pA, AA

2. RHIC Program: a long way to go Example: Quarkonia J/ ,  ’,  c,  (1S),  (2S),  (3S) u Key Idea: Melting in the plasma Suppression of states is determined by T C and their binding energy u Sequential disappearance of states:  Color screening  Deconfinement  QCD thermometer  Properties of QGP (Lattice  Experiment) u Fact: So far we have learned very little about the QGP from quarkonia despite it’s great potential  Stunning similarity of J/  suppression pattern at SPS and RHIC Suppression vs. Recombination An accident ? Theory ? No consistent description yet Big picture so far from: bulk (flow, ratios), high-p T physics Many key measurements (rare probes) are still to be addressed Examples are: Measurement of all onium states – large statistics needed  (1S),  (2S),  (3S) is easier to interpret - but harder to measure Need direct measure of Heavy Flavor (D) and correlations (see Ivan Vitev’s talk) We need: RHIC-II luminosities High statistics measurements in wide range of √s and A Detector upgrades A long breath …

3. Cross-fertilization of SPS↔RHIC(↔LHC) Many of the recent studies at the SPS were inspired by RHIC results. They would NEVER have been performed w/o RHIC! Same is true the other way around u e.g. low √s scan at RHIC to search for critical point (see Krishna’s talk) High-p T Measurements at SPS nucl-ex/0504001 CERES, S. Kniege (QM06) 3-particle correlations at SPS: Indication of conical emission. Mach cone at SPS ? AGS SPS RHIC SPS, Pb+Au Only if we look at SPS/RHIC/LHC will we be able to understand the whole  Excitation functions are key State of matter at SPS  (new) state at RHIC (sQGP)  LHC (wQGP?) We will need RHIC for a very long time Important questions: What will we miss at RHIC-II + mid-term upgrades? Will we need a 2 nd round of upgrades or new (specialized) experiments What studies at RHIC will be inspired by LHC ? pp

4. Thermalization:  At RHIC system thermalizes (locally) fast (   ~ 0.6 fm/c) u We don’t know why and how? Initial conditions?  Hydro models only valid for  >   Jet Quenching: u Refererence: E-loss in cold matter u d+A alone won’t do  need more precise handles u hadron formation, fragmentation see George Sterman’s talk Forward Region: u Suppression at forward rapidities Color Glass Condensate ? Gluon Distributions ? Questions w/o Answers … yet FF modification (parton energy loss) N. Armesto, J.Phys.G32:R367-R394,2006. It is getting worse at LHC: Ratios of gluon distribution functions for Pb versus x from different models at Q 2 = 5 GeV 2 : ?

5. Questions w/o Answers … Latest News: u Observe “E-loss” of direct photons Are we seeing the EMC effect? Many (all?) of these questions cannot be answered by studying A+A or p+A alone. We need a new level of precision: Handle on x, Q 2 Means to study effects exclusively RHIC is dominated by glue  Need to know G(x,Q 2 ) In short we need ep but especially eA  EIC but also (see slide 1+2) it needs to be in conjunction with a AA program covering large range of  s (FAIR/RHIC/LHC)