p 1 Hot Topics in Hot Matter 2012, Roy A. Lacey, Stony Brook University II. “We don’t stop playing because we grow old; we grow old because we stop playing.” - George Bernard Shaw I. We turn not older with years, but newer every day. - Emily Dickinson We look forward to many more years of productive collaboration! Two Reminders: יום הולדת שמח יצחק p

2Hot Topics in Hot Matter 2012, Roy A. Lacey, Stony Brook University Essential Point  The scaling properties of azimuthal anisotropy measurements at RHIC & the LHC, inform crucial mechanistic insights for characterization of the QGP?

Why Azimuthal Anisotropy Measurements?  This implies very specific scaling properties for flow and jet suppression (respectively), which can be tested experimentally  Scaling validation provide important insights, as well as straightforward probes of transport coefficients Scaling validation provide important insights, as well as straightforward probes of transport coefficients Roy A. Lacey, Stony Brook University; Ridge Workshop, INT, Seattle, May 7-11, 2012 pT < GeV/c Flow pT > GeV/c Jet suppression 3 Pressure driven (acoustic ) 3-4 < pT < 8-10 GeV/c Path length (∆L) driven More suppression Less suppression Transition Region Flow and Jet suppression are linked by Geometry & the interactions in the QGP Yield(  ) ~ 2 v n cos[2(  n )]

4 RHIC (0.2 TeV)  LHC (2.76 TeV) Power law dependence (n ~ 0.2)  increase ~ 3.3  Multiplicity density increase ~ 2.3  increase ~ 30% Lacey et. al, Phys.Rev.Lett.98:092301,2007 Relevant questions:  How do the transport coefficients evolve with T?  Any indication for a change in coupling close to T o ? Hot Topics in Hot Matter 2012, Roy A. Lacey, Stony Brook University Energy scan Why RHIC and LHC Measurements? The energy density lever arm

5 Hot Topics in Hot Matter 2012, Roy A. Lacey, Stony Brook University Jet suppression Probe Suppression (∆L) – pp yield unnecessary Jet suppression drives azimuthal anisotropy at high p T with specific scaling properties Suppression (L), Phys.Lett.B519: ,2001 For Radiative Energy loss: Modified jet More suppression Less suppression Fixed Geometry Path length (related to collision centrality)

6 Geometric Quantities for scaling A B  Geometric fluctuations included  Geometric quantities constrained by multiplicity density. Phys. Rev. C 81, (R) (2010) arXiv: σ x & σ y  RMS widths of density distribution Hot Topics in Hot Matter 2012, Roy A. Lacey, Stony Brook University

Specific p T and centrality dependencies – Do they scale? 7 Hot Topics in Hot Matter 2012, Roy A. Lacey, Stony Brook University High-pT v 2 measurements - PHENIX p T dependence Centrality dependence

High-pT v 2 measurements - CMS Specific p T and centrality dependencies – Do they scale? 8 arXiv: p T dependence Centrality dependence Hot Topics in Hot Matter 2012, Roy A. Lacey, Stony Brook University

9 High-pT v 2 scaling - LHC v 2 follows the p T dependence observed for jet quenching Note the expected inversion of the 1/√p T dependence arXiv: Hot Topics in Hot Matter 2012, Roy A. Lacey, Stony Brook University

10 ∆L Scaling of high-pT v 2 – LHC & RHIC Combined ∆L and 1/√p T scaling  single universal curve for v 2  Constraint for ε n arXiv: Hot Topics in Hot Matter 2012, Roy A. Lacey, Stony Brook University

11 Hot Topics in Hot Matter 2012, Roy A. Lacey, Stony Brook University ∆L Scaling of high-pT v 2 - RHIC Combined ∆L and 1/√p T scaling  single universal curve for v 2  Constraint for ε n

12 Jet v 2 scaling - LHC v 2 for reconstructed Jets follows the p T dependence for jet quenching Similar magnitude and trend for Jet and hadron v 2 after scaling Hot Topics in Hot Matter 2012, Roy A. Lacey, Stony Brook University (z ~.62) ATLAS 10-20%

13 Jet suppression from high-pT v 2 Jet suppression obtained directly from pT dependence of v 2 Compatible with the dominance of radiative energy loss arXiv: R v2 scales as 1/√p T, slopes encodes info on α s and q ˆ Hot Topics in Hot Matter 2012, Roy A. Lacey, Stony Brook University

R AA scales as 1/√p T ; slopes (S pT ) encode info on α s and q L and 1/√p T scaling  single universal curve Compatible with the dominance of radiative energy loss 14 arXiv: p T scaling of Jet Quenching ˆ, Phys.Lett.B519: ,2001 Hot Topics in Hot Matter 2012, Roy A. Lacey, Stony Brook University

15 Extracted stopping power Phys.Rev.C80:051901,2009  obtained from high-pT v 2 and R AA [same α s ]  similar  - medium produced in LHC collisions less opaque! (note density increase from RHIC to LHC) arXiv: arXiv: Conclusion similar to those of Liao, Betz, Horowitz,  Stronger coupling near T c ? q RHIC > q LHC ˆ q LHC ˆ Hot Topics in Hot Matter 2012, Roy A. Lacey, Stony Brook University

Scaling properties of Flow Hot Topics in Hot Matter 2012, Roy A. Lacey, Stony Brook University16

The Flow Probe 17 Idealized Geometry Crucial parameters Actual collision profiles are not smooth, due to fluctuations! Initial Geometry characterized by many shape harmonics (ε n )  drive v n Initial eccentricity (and its attendant fluctuations) ε n drive momentum anisotropy v n with specific scaling properties Acoustic viscous modulation of v n Staig & Shuryak arXiv: Isotropic p Anisotropic p Hot Topics in Hot Matter 2012, Roy A. Lacey, Stony Brook University Yield(  ) =2 v 2 cos[2(   ]

Hydrodynamic flow is acoustic Characteristic n 2 viscous damping for harmonics  Crucial constraint for η/s Associate k with harmonic n 18 Hot Topics in Hot Matter 2012, Roy A. Lacey, Stony Brook University Note: the hydrodynamic response to the initial geometry [alone] is included ε n drive momentum anisotropy v n with modulation Modulation  Acoustic

Constraint for η/s & δf Deformation 19 Characteristic 1/√p T dependence of β  Important constraint for δf and η/s Hot Topics in Hot Matter 2012, Roy A. Lacey, Stony Brook University

ATLAS-CONF High precision double differential Measurements are pervasive Do they scale? Hot Topics in Hot Matter 2012, Roy A. Lacey, Stony Brook University v n (ψ n ) Measurements - ATLAS

21 Hot Topics in Hot Matter 2012, Roy A. Lacey, Stony Brook University Acoustic Scaling β shows weak centrality dependence for a broad centrality range

Acoustic Constraint Characteristic viscous damping of the harmonics validated  Important constraint Wave number 22 LHCRHIC Hot Topics in Hot Matter 2012, Roy A. Lacey, Stony Brook University arXiv: at RHIC; 25-30% increase for LHC ε n drive momentum anisotropy v n with modulation

23 β scales as 1/√p T  Important constraint Note similarity to pT dependence of jet suppression Hot Topics in Hot Matter 2012, Roy A. Lacey, Stony Brook University Constraint for η/s & δf ~ 1/4π at RHIC; small increase for LHC

24 Roy A. Lacey, Stony Brook University; ECT 2012, 2-6 July, Trento, Italy Centrality dependence reflect eccentricity ratio Further constraint for ε n Ascaling contd. Acoustic scaling contd. Scaling validated for v n Similar scaling at the LHC

25 Flow Saturates for GeV Hot Topics in Hot Matter 2012, Roy A. Lacey, Stony Brook University  No sizeable beam energy dependence observed for v 2 and v 3 for each particle species  flow saturates for GeV  Soft EOS

26 Hot Topics in Hot Matter 2012, Roy A. Lacey, Stony Brook University  Flow increases from RHIC to LHC Sensitivity to EOS increase in  Proton flow blueshifted [hydro prediction] Role of radial flow Role of hadronic re- scattering? Flow increases from RHIC to LHC

27 Flow is the LHC Scaling for partonic flow validated after accounting for proton blueshift Larger partonic flow at the LHC Hot Topics in Hot Matter 2012, Roy A. Lacey, Stony Brook University

KE T & scaling validated for v n  Partonic flow 28 v n PID scaling Flow is RHIC Hot Topics in Hot Matter 2012, Roy A. Lacey, Stony Brook University

Remarkable scaling have been observed for both Flow and Jet Quenching They lend profound mechanistic insights, as well as New constraints for estimates of the transport and thermodynamic coefficients! 29  R AA and high-pT azimuthal anisotropy stem from the same energy loss mechanism  Energy loss is dominantly radiative  R AA and anisotropy measurements give consistent estimates for  R AA and anisotropy measurements give consistent estimates for  R AA for D’s give consistent estimates for  R AA for D’s give consistent estimates for  The QGP created in LHC collisions is less opaque than that produced at RHIC  Flow is acoustic Flow is pressure driven Obeys the dispersion relation for sound propagation  Flow is partonic exhibits scaling  Constraints for: initial geometry small increase in η/s from RHIC ( ~ 1/4π) to LHC What do we learn? Summary Hot Topics in Hot Matter 2012, Roy A. Lacey, Stony Brook University

End 30 Hot Topics in Hot Matter 2012, Roy A. Lacey, Stony Brook University

Scaling properties of Jet Suppression Hot Topics in Hot Matter 2012, Roy A. Lacey, Stony Brook University31

32 Relation between quenching and flow Hot Topics in Hot Matter 2012, Roy A. Lacey, Stony Brook University

33 Hot Topics in Hot Matter 2012, Roy A. Lacey, Stony Brook University For partonic flow, quark number scaling expected  single curve for identified particle species v n Is flow partonic? Note species dependence for all v n

34 Extracted stopping power Phys.Rev.C80:051901,2009  obtained from high-pT v 2 and R AA [same α s ]  similar  - medium produced in LHC collisions less opaque! arXiv: arXiv: Conclusion similar to those of Liao, Betz, Horowitz,  Stronger coupling near T c ? q RHIC > q LHC ˆ q LHC ˆ Hot Topics in Hot Matter 2012, Roy A. Lacey, Stony Brook University

35 RHIC and the LHC Hot Topics in Hot Matter 2012, Roy A. Lacey, Stony Brook University  Multiplicity-weighted PIDed flow results reproduce inclusive charged hadron flow results at RHIC and LHC respectively  Charge hadron flow RHIC & LHC

p Conjectured Phase Diagram 36 Quantitative study of the QCD phase diagram is central to our field Hot Topics in Hot Matter 2012, Roy A. Lacey, Stony Brook University Interest  Location of the critical End point  Location of phase coexistence lines  Properties of each phase All are fundamental to the phase diagram of any substance Spectacular achievement: Validation of the crossover transition leading to the QGP Full characterization of the QGP is a central theme at RHIC and the LHC

Characterization of the QGP produced in RHIC and LHC collisions requires: I. Development of experimental constraints to map the topological, thermodynamic and transport coefficients II. Development of quantitative model descriptions of these properties QGP Characterization? Hot Topics in Hot Matter 2012, Roy A. Lacey, Stony Brook University 37 Experimental Access: Temp/time-averaged constraints as a function of √s NN (with similar expansion dynamics) (I) Expect space-time averages to evolve with √s NN (II)

R AA Measurements - CMS Specific p T and centrality dependencies – Do they scale? 38 Eur. Phys. J. C (2012) 72:1945 arXiv: Centrality dependence p T dependence Hot Topics in Hot Matter 2012, Roy A. Lacey, Stony Brook University

L scaling of Jet Quenching - LHC R AA scales with L, slopes (S L ) encodes info on α s and q Compatible with the dominance of radiative energy loss 39 arXiv: ˆ, Phys.Lett.B519: ,2001 Hot Topics in Hot Matter 2012, Roy A. Lacey, Stony Brook University

40 Phys.Rev.C80:051901,2009 Hot Topics in Hot Matter 2012, Roy A. Lacey, Stony Brook University L scaling of Jet Quenching - RHIC R AA scales with L, slopes (S L ) encodes info on α s and q Compatible with the dominance of radiative energy loss ˆ

R AA scales as 1/√p T ; slopes (S pT ) encode info on α s and q L and 1/√p T scaling  single universal curve Compatible with the dominance of radiative energy loss 41 arXiv: p T scaling of Jet Quenching ˆ, Phys.Lett.B519: ,2001 Hot Topics in Hot Matter 2012, Roy A. Lacey, Stony Brook University

Consistent obtained 42 Hot Topics in Hot Matter 2012, Roy A. Lacey, Stony Brook University q LHC ˆ Heavy quark suppression

43 Hot Topics in Hot Matter 2012, Roy A. Lacey, Stony Brook University Jet suppression from high-pT v 2 - RHIC Jet suppression obtained directly from pT dependence of v 2 R 2 scales as 1/√p T, slopes encodes info on α s and ˆqˆq

Acoustic Constraint Characteristic viscous damping of the harmonics validated  Important constraint Wave number 44 LHCRHIC Hot Topics in Hot Matter 2012, Roy A. Lacey, Stony Brook University arXiv: at RHIC; small increase for LHC