Quark Matter 2009 PreSummary Puzzles Progress Prospects W

Quark Matter 2009 Pre-Summary: Puzzles, Progress, Prospects W. A. Zajc Physics Department Columbia University, New York, NY ( this talk available at http: //www. phenix. bnl. gov/phenix/WWW/publish/zajc/sp/presentations/QM 09 ) 30 -Mar-09 W. A. Zajc

Preface Those of us of “a certain age”… l Recall when movie theaters showed a cartoon before the main attraction. l l l This talk is that cartoon prior to the conference (Ed Wenger, QM 08) 30 -Mar-09 W. A. Zajc

Our Developing Field l SPIRES query for all publications with QGP, SQGP, QUARK-GLUON PLASMA, QCD PLASMA, STRONGLY COUPLED PLASMA, STRONGLY-COUPLED PLASMA, RHIC PLASMA l"Quark in their title: Gluon Plasma" Publications Versus Time l 150 ? l. SPIRES Entries l 100 l 50 l 1970 l 1975 l 1980 l 1985 l 1990 l 1995 l 2000 l 2005 l 2010 l. Year 30 -Mar-09 W. A. Zajc

Caveats l l l Given the richness and productivity… This talk is a sampling, not a survey Provide hints of The Shape of Things to Come 30 -Mar-09 W. A. Zajc

Maturation l When I was a child, I spake as a child, I understood as a child, I thought as a child: but when I became a man, I put away childish things. q. Paul, l 30 -Mar-09 Corinthians 13: 11 Some childish things: W. A. Zajc

Puzzles and Factors of “Two” l l 30 -Mar-09 The point being… Our field has matured to the point where resolving factors of “two” (or sometimes more) is essential to our quantitative understanding of thermal QCD matter W. A. Zajc

The DLS Puzzle l Long-standing “DLS Puzzle” of pair excess in 0. 2 < M < 0. 5 Ge. V l QM 08: Confirmed by HADES l PANIC 08: Explained by p+p, p+d HADES measurements q Insights from theoretical modeling of N-N bremsstrahlung, D Dalitz, etc. q 30 -Mar-09 W. A. Zajc

Lesson Know your reference. 30 -Mar-09 W. A. Zajc

The HBT Puzzle l Early hydrodynamic simulations provided q. Excellent descriptions of spectra and elliptic flow: q. Poor descriptions of HBT radii: q. Rout/Rside off by a factor of ~2 (Early thermalization at RHIC, U. Heinz and P. Kolb, hep-ph/0111075 ) 30 -Mar-09 W. A. Zajc

The HBT Puzzle Resolved l l The Long Slow Death of the HBT Puzzle, S. Pratt, 0812: 4714 Important to incorporate several “trivial” effects: q Pre-equilibrium flow q Stiffer EOS q Non-zero viscosity q FSI in p-p wavefunction 30 -Mar-09 W. A. Zajc

Lesson Details matter. 30 -Mar-09 W. A. Zajc

The J/Y Puzzle l l l J/psi Suppression by Quark-Gluon Plasma Formation, T. Matsui and H. Satz, Phys. Lett. B 178: 416, 1986. “Our” most famous paper (1229 cites) Yet “puzzles” remain: q Still (? ) evolving value of TD /TC q Coalescence (anti)-contributions q Cold nuclear matter effects q Feed-down contributions q RAA(SPS) = RAA(RHIC) 30 -Mar-09 W. A. Zajc

Cold Nuclear Matter (CNM) Effects l RHIC: q Run-3 q Error d+Au data poorly constrain CNM band: u. Will increase from corrected propagation u. Will decrease significantly from Run-8 d+Au SPS: NA 60 new results from p. A at 158 Ge. V W. A. Zajc 30 -Mar-09 l

Cold Nuclear Matter (CNM) Effects l RHIC: q Run-3 d+Au data poorly constrain CNM q New Run-3 error band: 0903. 4845 q Error band: Will decrease significantly from Run-8 d+Au l SPS: NA 60 - new results from p. A at 158 Ge. V 30 -Mar-09 W. A. Zajc

Over-reaching 30 -Mar-09 W. A. Zajc

Reaching 30 -Mar-09 W. A. Zajc

‘Heavy’ Lifting Is Underway l In situ measurements of ‘backgrounds’ : cc J/y : 20 -40% l y’ J/y : ~8% l B J/y : ~4% (@RHIC) l l. STAR l l Preliminary Polarization to test production models Flow to test coalescence models… 30 -Mar-09 W. A. Zajc

Lessons 30 -Mar-09 Know your reference. Details matter. Control your control measurement. W. A. Zajc

The Shape of Things to Come 30 -Mar-09 W. A. Zajc

Event Morphology l Oxford English Dictionary: q 30 -Mar-09 orig. and chiefly Science: Shape, form, external structure or arrangement, esp. as an object of study or classification. Also: a particular shape, form, or external structure, esp. of (a part of) an organism, landform, etc.

PHOBOS QM 08 l Long-range structure in Dh : l Keep in mind: q. Integrated ridge yield ~ few % q. It’s pseudo-rapidity (i. e. , an angle) l See J. Nagle talk for model comparisons 30 -Mar-09 W. A. Zajc

Details Matter: g*’s l l PHENIX: g* e+e- NA 60: g* m+m- Being done and to do: p+p, p+A, flow, polarization, models, … 30 -Mar-09 W. A. Zajc

A Long Time Ago… 1996 2009 l l Jet quenching in the opposite direction of a tagged photon in high-energy heavy ion collisions, Wang, X. N. , Huang, Z. and Sarcevic, I. , Phys. Rev. Lett. 77: 231 -234, 1996. hep-ph/9605213 Photon-Hadron Jet Correlations in p+p and Au+Au Collisions at s. NN = 200 Ge. V, PHENIX Collaboration, A. Adare et al. , 0903. 3399 30 -Mar-09

(Real) Jet Quenching l Known ~forever that fake jets from soft fluctuations dominate to very high p. T. q q 1993: PHENIX Conceptual Design Report: u A feature ! u “jets via leading particle distributions to study the energy loss of high energy quarks inside the plasma” 1999: Finger physics 2009: Expect results from true jet reconstruction at RHIC q Sevil Salur, Plenary to 30 -40 Ge. V/c ! q Yue Shi Lai, Parallel 2 A 30 -Mar-09 l } W. A. Zajc

Quantitative p. QCD l l Systematic Comparison of Jet Energy-Loss Schemes in a Realistic Hydrodynamic Medium, S. A. Bass et al. , 0808. 0908 A (valuable!) exercise in Procrustean reductionism. Good news: “Bad” news: 30 -Mar-09

Comment l l Yes- to some extent this is an illustration of the “fragility” of RAA More differential more sensitive q IAA q RAA l versus reaction plane However- not the real issue (see B. Cole QM 08) q Instead: consistent treatment of collisional + radiative terms, finite L, expanding medium, coupling constant, kinematic cut-offs, assumed scale hierarchies, … W. A. Zajc 30 -Mar-09

The Difficulties with Hydro l Seemingly insurmountable: q q q q Unknown Initial Conditions Eccentricity fluctuations Unknown equation of state Instabilities, acausal effects in relativistic viscous hydro Hadronic rescattering effects Bulk viscosity Numerical viscosity Finite size, core/corona effects

Implementing and Testing l Examples q P. Romatschke and U. Romatschke, Phys. Rev. Lett. 99: 172301, 2007 q H. Song and U. Heinz, Phys. Rev. C 78, 024902, 2008 q M. Luzum and P. Romatschke hys. Rev. C 78: 034915, 2008. 7 fm/c 3 fm/c 1 fm/c 30 -Mar-09

Concordance l BNL, April 2008: q q Workshop on Viscous Hydrodynamics and Transport Models in Heavy Ion Collisions Workshop Summary M. Luzum and P. Romtschke Phys. Rev. C 78: 034915, 2008. 30 -Mar-09 W. A. Zajc

A Long Time Ago (1985) l Dissipative Phenomena in Quark-Gluon Plasmas, P. Danielewicz and M. Gyulassy, Phys. Rev. D 31, 53, 1985. Noted several restrictions on smallest allowed h : l Most restrictive: l q q q l > h/<p> h>~n/3 But recall s = 3. 6 n for the quanta they were considering h/s > 1 / (3. 6 x 3) ~ 1 / (4 p) 30 -Mar-09 !!

(Minimal) Ad. S / CFT Graviton with 5 -momentum k in bulk satisfies k k = 0 described by numbers 4 4 Those numbers describe virtual gauge 4 -d quanta on boundary 30 -Mar-09 ( Adopted from S. Brodsky figure )

Comparison of Estimates R. Lacey et al. : PRL 98: 092301, 2007 H. -J. Drescher et al. : ar. Xiv: 0704. 3553 S. Gavin and M. Abdel-Aziz: PRL 97: 162302, 2006 p. Tfluctuations STAR v 2 PHOBOS v 2 PHENIX & STAR Various 2 nd order hydro calculations A. Adare et al, PRL 98: 172301, 2007 Heavy flavor drag, flow; PHENIX 30 -Mar-09 conjectured quantum limit

Knowing Knudsen l Experimental fit of Knudsen number K = lmfp/R on way to h/s estimate: Preliminary l. Still 10 -Oct-08 to do- Understand systematics ! q. Assumed T q. Assumed s q. Boltzmann transport

Comparison of Estimates R. Lacey et al. : PRL 98: 092301, 2007 H. -J. Drescher et al. : ar. Xiv: 0704. 3553 S. Gavin and M. Abdel-Aziz: PRL 97: 162302, 2006 p. Tfluctuations STAR v 2 PHOBOS v 2 PHENIX & STAR Various 2 nd order hydro calculations A. Adare et al, PRL 98: 172301, 2007 Heavy flavor drag, flow; PHENIX 30 -Mar-09 conjectured quantum limit

Recombination l Recombination works: Deal with it l Miklos Gyulassy: “One of the most remarkable ‘I don’t understand’ phenomena”

Implications for D. O. F l l While tempting to identify the coalescence patterns with “underlying quark degrees of freedom”… Much work still needed to reconcile with ‘absence’ of quasiparticles when h/s near quantum bound Quasi-Particle Degrees of Freedom versus the Perfect Fluid as Descriptors of the Quark-Gluon Plasma, L. A. Levy et al. , Phys. Rev. C 78: 044905, 2008. 0709. 3105 q Quantum Criticality and Black Holes, S. Sachdev and M. Mueller, 0810. 3005 : q “The theory of the quantum critical region shows that the transport coefficients, and the relaxation time to local equilibrium, are not proportional to a mean free scattering time between excitations, as is the case in the Boltzmann theory of quasiparticles 30 -Mar-09 W. A. Zajc

Critical Point - Theory l l 30 -Mar-09 Better called critical band…. M. Stephanov, Phase Diagram of QCD: The Critical Point, GSI Symposium, March 2009 W. A. Zajc

Onward to the Critical Point l RHIC Run-8: energy segment at s. NN=9. 2 Ge. V q STAR- first results from ~3000(!) events: q Low 30 -Mar-09 W. A. Zajc

The Future Is (almost) Now l Incredible “Golden Era” for our field: q NICA q GSI-FAIR q SPS q RHIC-II q LHC 30 -Mar-09 W. A. Zajc

Un-Summary l Not covered q LQCD- next talk (P. Petreczky) q b/c separation, Upsilons q d+A, CGC q Unconventional wisdom- (Z. Chajecki) q LHC predictions (U. Wiedemann) q Eccentricity fluctuations (T. Hirano, A. Poskanzer) q CP Violation ! (S. Voloshin) l And much more…. 30 -Mar-09 W. A. Zajc

Pre-Summary "Those who cannot remember the past are condemned to repeat it. “ l George Santayana, Reason in Common Sense l 30 -Mar-09 Know your reference. Details matter. Control your control measurement. W. A. Zajc

Summary l l Because we have learned from history Our field is poised for the next decade of q. Exploration ( discoveries!) q. Characterization q. Quantification of matter throughout the QCD phase diagram and for many Quark Matters to come ! 30 -Mar-09 W. A. Zajc

Thank you and enjoy the conference ! 30 -Mar-09 W. A. Zajc

The Charm Puzzle l l Conserved ! Loses energy: § § PHENIX and STAR RAA ~ consistent RAA ~ unchanged in region where b’s should dominate • Flows § Again, little evidence for decoupling of b’s 30 -Mar-09 W. A. Zajc

The Charm Puzzle l Being addressed: STAR § § § 10 -fold reduction in material budget Work on understanding § § § PHENIX § § momentum resolution e/p from data Cross checks via e+e- spectrum Together § 30 -Mar-09 Joint effort to study/resolve discrepancy W. A. Zajc

Lesson (? ) The devil is in the details. 30 -Mar-09 W. A. Zajc

A Clear Prediction l l PBM, QM 06: Npart dependence of J/Y per charm pair as test of statistical hadronization and deconfinement. 30 -Mar-09 W. A. Zajc

30 -Mar-09 W. A. Zajc

Overall Scaling of Elliptic Flow at RHIC Particles flow with common velocity field 49 Roy A. Lacey, 4 th Int. Workshop on High p. T Phy

30 -Mar-09 W. A. Zajc

Recombination Revisited l l Apply constituent scaling to “ 0 -th moment” of flow Interplay (p. T, KET), (v. T, T) helps understand d. o. f. ? 30 -Mar-09 W. A. Zajc

Ongoing Work on QP’s l l 30 -Mar-09 Hadronic modes and quark properties in the quarkgluon plasma, M. Mannarelli and R. Rapp, hep-ph/0505080 Quasi-particle model for lattice QCD: Quark-gluon plasma in heavy ion collisions, V. Chandra and V. Ravishankar, 0812. 1430 Parton transport and hadronization from the dynamical quasiparticle point of view, W. Cassing and E. L. Bratkovskaya, 0808. 0022 The Hot non-perturbative gluon plasma is an almost ideal colored liquid, A. Peshier and W. Cassing, hep-ph/0502138 W. A. Zajc

Paucity of World’s p+p Data 30 -Mar-09 W. A. Zajc

l 30 -Mar-09 Beyond h/s = 1/4 p, A. Buchel, R. C. Meyers and A. Sinha, 0812. 2521 W. A. Zajc

30 -Mar-09 W. A. Zajc

Speaking of Cartoons l What is thing ? ? l Surely not the space-time development: ? W. A. Zajc

Restating the “Obvious” l A reminder: q. All nuclei are finite q. Most nuclei are round l No nuclei are q. Infinite q. Cylindrical q. Sharp spheres q…. 30 -Mar-09 W. A. Zajc