The Quark-Gluon-Plasma Is Found at RHIC. (but experimentalists have Yet to recognize it)

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1 The Quark-Gluon-Plasma Is Found at RHIC (but experimentalists have Yet to recognize it) Miklos Gyulassy Columbia University Three major discoveries at RHIC 1) Conclusive evidence for Bulk P QCD collective flow of 5000, K, p 2) Conclusive evidence for pqcd jet quenching in Au+Au at RHIC 3) Conclusive evidence of jet unquenching in d+au: Null Control All 3 are explained by QCD dynamics 1) My Conclusion: 1+2+3=QGP Au+Au at 200 AGeV made Bulk QGP Matter E / V( τ ~ 0.2 fm / c) 100 ε 0 Gyulassy 1

2 Outline 1. Overview of 3 convergent lines of evidence 2. Bulk Collective Flow and the QCD Equation of State 3. Parton Diagnostics: Jet Quenching 4. The D+Au Null Control 5. Conclusion: The QGP is found Gyulassy 2

3 Theoretical Prediction QGP Asymptotic Freedom Deconfinement Chiral Symmetry Experimental Tools PHENIX X PHOBOS X RHIC X BRAHMS X STAR 2001 Au+Au 130 AGeV 2002 Au+Au, p+p 200 AGeV 2003 D+Au 200 AGeV Gyulassy 3

4 3 rd rd RHIC Milestone BRAHMS STAR Gyulassy 4

5 XN Wang, MG BULK P QCD Hard pqcd Null Control PHOBOS BRAHMS Gyulassy 5

6 Mini-Jet quenching and the Baryon anomaly V.Topor Pop et al, nucl-th th/ v4 de/dx dx=0.0 de/dx dx=0.5 de/dx dx=2.0 K? p? de/dx dx=0.0 de/dx dx=0.5 de/dx dx=2.0 Gyulassy 6

7 What is a Quark Gluon Plasma? How will we recognize it in the lab if we don t know what it looks like? We need an operational QGP definition! Gyulassy 7

8 My 3 Part Definition of a QGP 1. A form of matter (many body dynamical system) with a unique set of Bulk (collective) phenomena and partonic diagnostics 2. which are calculable in the deconfined (Colored) quark-gluon basis of QCD 3. And which can be turned on or off via Control experiments Examples of NON-QGP systems in QCD 1. e+e- -> q q g 2 ok but not 1 2. p+p -> pi, K, p 2 ok but not 1 3. e+a -> jets 2 ok but not 1 4. Nucleus A 1 ok but not 2 5. SIS,AGS res. gas 1 ok but not 2 6. SPS A+A 1 ok but 2~OK but not 3! Gyulassy 8

9 SPS AA discovered important QGP PRE-requisites 1. Statistical (microcanonical) phase space hadronization Final Hadron degrees of freedom equilibrated (NA49) Even hyperons (WA97) T chem ~170 MeV~T c 2. Bulk Radial Flow v T ~0.6 c transverse Doppler shift (NA49) Pion wind blows for a long time; Baryons windsurf Conclusive evidence for Hadronic FSI 3. QCD probe cc ->J/Psi found strongly suppressed (NA50) BUT phenomenon Failed to turn off in p+a, S+A Control! 4. High p T pqcd 0 probe Failed to quench due to initial state (Cronin) physics! QCD parton probes at SPS failed the Null Control test of QGP Gyulassy 9

10 First Line of Evidence for QGP at RHIC Bulk Elliptic Collective Flow P QCD EOS 1 1 QGP RHIC Initial spatial anisotropy y Final momentum anisotropy p y x µν T (x) = 0 µ p x Gyulassy 10

11 Unfortunately One Leg Tables Are Unstable! QGP RHIC 1 QGP Gyulassy 11

12 Second Line of Evidence for QGP at RHIC Bulk Elliptic Flow 1 1 QGP RHIC 2 2 Jet Quenching 1/N evt 1/2π 1/p t dn/dp t (GeV/c) Au +Au -> 0 + X at E cm = 130 PHENIX AGeV preliminary 10% 75-92% UA1(130) scaled to 5% central scaled to 80-92% central p t (GeV/c) Gyulassy 12

13 BUT Two Legged Tables are STILL Unstable! 1 QGP QGP 2 RHIC 2 2 Gyulassy 13

14 Third Line of Evidence for QGP at RHIC Bulk P QCD 1 3 QGP 2 Parton pqcd 1 3 RHIC 2 D+Au Null Control + pp Calibration No Quench D+A! Strong Quench A+A Gyulassy 14

15 Three Legs Stable Even If Unequal Three Lines Converge to QGP at RHIC Bulk P QCD 1 1 Null Control 3 QGP 3 RHIC 2 2 Parton pqcd 1. Bulk P QCD Collective Elliptic Flow 2. Parton pqcd Jet dynamics 3. p+p Calibration and d+a Null Control QGP =P QCD + pqcd + da = v 2 + (R AA +I AA ) + R da QCD AA AA da Gyulassy 15

16 Outline 1. Overview of 3 convergent lines of evidence 2. Bulk Collective Flow and the QCD Equation of State 3. Parton Diagnostics: Jet Quenching 4. The D+Au Null Control 5. Conclusion: The QGP is found Gyulassy 16

17 The QGP Equation of State from LQCD RHIC P K T B 1 4 QCD 3 QCD vac ε K T+ B 4 QCD QCD vac ~ 160 MeV F. Karsch et al Goal is to test this unique prediction of QCD : The softenning of P QCD c s ~0 Near T c ~160 MeV N. Christ et al Gyulassy 17

18 Bulk Collective Flow of QCD matter { } µν µ ν µν T = u u ( ε (T) + P(T)) g P(T) = 0 µ µ QCD EOS H. Stocker, W. Greiner (1980) P.Kolb, U. Heinz et al D.Teany, E. Shuryak et al T. Hirano, Y. Nara Initial spatial anisotropy y Final momentum anisotropy p y x µν T (x) = 0 µ p x Elliptic Flow dn dydp d 2 T { T) cos ( 2φ) } (y,p T) v (p φ = ρ + + Gyulassy 18

19 The Nuclear Geometry Experimental Knob Initial Geometry Experimental Handles 2 b part A 2 b b A 2 -σ T (s- ) N (b)=2 d s T (s+ )(1-e ) de T /d E ZDC T ( b) dz ρ ( z, b) 2ρ R b 2 2 A = A 0 2 b b AB ( ) A( 2) B ( 2) T b = d s T s + T s dn ch /d N BBC coll AA ~ πr 2 σ A 4 /3 N (b) = σ T (b) < ~ A ~ Gyulassy 19

20 Time evolution of asymmetry in non-central collisions P.F.Kolb, J. Sollfrank and U. Heinz, PRC 62 (2000) evolution initial energy of the density energy distribution density Spatial eccentricity ε x = y 2 x 2 y 2 + x 2 Momentum anisotropy ε p = T xx T yy T xx + T yy Elliptic flow generated t<3 fm/c! Zhang, Molnar Gyulassy 20

21 Observed Elliptic Flow at RHIC saturates hydro limit { } µν µ ν µν T = u u ( ε (T) + P(T)) g P(T) = 0 µ µ P.Kolb U. Heinz, et al, D.Teany, E. Shuryak et al T. Hirano, Y. Nara The most sensitive Barometric probe of the QCD Equation of State P(T) M h dependent v 2 (p T ) Initial spatial anisotropy y Final momentum anisotropy p y x µν T (x) = 0 µ p x Gyulassy 21

22 nucl-ex/ Hydro: Gyulassy 22

23 Bulk Hydro Asymmetric Jet Quenching Gyulassy 23

24 Below RHIC energies, QCD hydro over-predicts elliptic flow! v 2 (E cm ) QGP hydro for the FIRST time at RHIC! CERES AGeV 17 AGeV CERES/SPS 2 2 dn ch / dyd x (fm ) Gyulassy 24

25 S.Soff Soff, S.A. Bass, M. Bleicher, H.Stoecker Stoecker, Walter Greiner nucl-th th/ Resonance/String Transport UrQMD explains SPS Sub-Hydro Flows v1 and v2 Gyulassy 25

26 Elliptic Flow follows Bulk dn/dy dy BRAHMS Au+Au 200 AGeV 5% centrality; nucl-ex/ Gyulassy 26

27 Summary Part I: 1) BULK Elliptic azimuthal flow of 1000 s of pions in non-central A+A is found at all energies, AGS, SPS, RHIC 2) However, only above 130 AGeV does the collective flow reach the hydrodynamic limit (dn ch /dyd 2 r > 25/fm 2 ) 3) The hadron flavor dependence of v 2 (p T ) requires soft QCD equation of state c s ~0 for T~T c ~160 MeV Is this the evidence for the production of equilibrated QGP? How can we know if quark gluon degrees of freedom are relevant? Gyulassy 27

28 Outline 1. Overview of 3 convergent lines of evidence 2. Bulk Collective Flow and the QCD Equation of State 3. Parton Diagnostics: Jet Quenching 4. The D+Au Null Control 5. Conclusion: The QGP is found Gyulassy 28

29 pqcd -> 0 in central Au+Au E cm Buys Gluons!!! Gyulassy 29

30 pqcd Calibration to p+p Baseline MG, I Vitev, XN Wang, Phys.Rev.Lett Lett.86: : , ,2001 Gyulassy 30

31 p T Distribution of Charged Particles Bulk Phobos Preliminary G.Roland Tail We can use this tiny calibrated pqcd tail to probe the QGP Bulk! Gyulassy 31

32 The high p T window at RHIC is now wide open Au-Au nucl-ex/ nucl-ex/ p+p-> hep-ex/ STAR PRL 89, Gyulassy 32

33 Pion Quenching at 200 AGeV PHENIX binary pp T R AA p ( T ) = 2 events pp T = D. d Enterria QM02 /dp d / inelastic (d ) N η σ σ 2 d η 1/N AA d /dp N SPS Cronin effect RHIC Jet Quenching PHENIX Preliminary binary scaling Gyulassy 33

34 Jet Quenching and Tomography Ivan Vitev, Peter Levai, Xin-Nian Wang, MG Reviewed in nucl-th th/ Single Hadron Tomography g g T T g jet p p Di-Hadron Tomography g g L 2 X L 1 X X g g p L( φ) 1 dn 2 πr dy τ ρ τ 3 p E GLV C C α l τ, Jet T µ L ( τ ) T s n 2 d r( ) Gyulassy 34

35 QCD Bethe-Heitler QGP Multiple Collision Non-abelian Radiative Energy Loss E = α ω E 10GeV E Thick Thick Plasma Limit c 2 2 < ω = 60 GeV q L c λ 2 Thin Thin Plasma Limit L ( ) 5fm L/ λg Opacity Expansion Ivan Vitev NPB 595 Phys.Lett Lett.B538:282.B538: , ,2002 (1 x) E x E (1) dng 2E E αsπ CR Log L( ) 2 2 φ 4 πr dy µ L Gyulassy 35

36 Thick vs Thin Plasma de/dx dx E τ f ω 2 k L 2 2 τ f ( ω ) < L if ω < ω = c 2 λ g µ τ 0 = L BDMS-Z τ 0 = 0 L GLV-WW WW-SW Gyulassy 36

37 Screened Yukawa 2 µ i { π (q + µ ) δ ( q )} i i i x x z = z z k k k 1 L ~ n + 1 LPM effect Inverse Formation Times Scatt amplitudes GLV: Nucl.Phys.B594(2001) Gyulassy 37

38 BDMPS-Z Asymptotic Approach to de/dx dx τ f x P 2 k + τ = 0 L f + 2 If L τ f λ µ, then k µ, τf x P λ g / µ λg 2 L dn g / g N coh =, and x CRαsNcoh CRαs L + τf dx x P f g coh R s fac dx τ µ λ L If τ L λ µ, then k µ, τ x P λ /( µ L) f g λg dn µ N = 1, and x C α for x > x = P L λ g 1 2 Gyulassy 38

39 dn c Initial Jet distribution ρ (p) = ~ dyd p p g g 2 n 7 dp pπ No medium Pion distribution ρ π(pπ) = ρ g(p) Dπ/ g(z = p ) p In medium p p p(p) p( 1 ε) D(z) D' (z) = D (z' = ) p θ( 1 ε z) z 1 ε 1 ε dp 1 pπ QuenchedPions ρ π(p π, ε) = ρ g (p) ( 1 ε ) Dπ/ g(z' = p( 1 ε )) p pπ ( 1 ε ) n quenched n 2 For ρg(p) 1/p : ρ (p π) = ( 1 ε) ρg( p π) π π π π ρ (p, ε) Quench Factor S = = ( 1 ε) = ( 1 Z ε ) ρ (p, 0) π n 2 n 2 π Fluctuations reduce E by factor Z ~ 0. 5 Gyulassy 39

40 ( ) shad dn = T f f dσ P( E) D AB π AB a/a b/b ab c π/ c k T I.Vitev, MG GRV EKS BKK GLV dn g /dy=1100 Absolute scale pqcd jet tomography Gyulassy 40

41 Quenching and Mono-Jets STAR: 200 GeV Au+Au / p+p Au+Au p + p Hadron suppression and disappearance of back-to-back jet are correlated! STAR PRL 90, STAR, AGS Users Meeting May 15, 2003 Gyulassy 41

42 STAR: C. Adler et al. Phys. Rev. Lett. 90, (2003) Leading hadron fragments outside QGP Gyulassy 42

43 Single Hadron Tomography from SPS, RHIC, LHC Ivan Vitev and MG, Phys.Rev.Lett. 89 (2002) 1) Cronin enhancement dominates at SPS 2) Cronin+Quench+Shadow conspire to give ~ flat R AA ~N part /N bin bin at RHIC dn g /dy ~ > r ~100 r g 0 3) Predict sub N part quench, part positive p T slope of R at LHC Gyulassy 43

44 Centrality Dependence of Quenching PHENIX AuAu 200: nucl-ex/ Consistent With GLV τ R dn ( ) GLV τ ρ τ τ 2 πr dy E d, r( ) N g 2 /3 part Gyulassy 44

45 STAR: C. Adler et al. Phys. Rev. Lett. 90, (2003) Correlation of Associated hadrons 2<pT pt<4 GeV with triggered 4<pT pt<6 Gyulassy 45

46 Azimuthal v 2 (p t ) Tomography K.Filimonov QM02 D.Molnar, MG Hydro ρ ˆ QGP( τ,x0 + n τ) STAR Preliminary Deviation from hydro above p T > 2 GeV/c and approximate Saturation of v 2 explained by finite asymmetric energy loss of jets in noncentral AA MG, I. Vitev, X.N. Wang PRL86(01) 2537 Gyulassy 46

47 Summary Part II: 1) Strong suppression of p T >4GeV hadrons observed at RHIC as predicted due to jet quenching in opaque QCD matter 2) Jet tomographic analysis indicates that QGP matter has an initial energy density ~ 100 times nuclear matter 3) Centrality dependence of mono-jet production consistent with GLV radiative gluon energy loss 2/3 d ττρτ (,x( τ)) N part Is this then the evidence for the production of a QGP? We must still rule out strong initial state gluon shadowing! [as suggested by Kharzeev, Levin, McLerran (CGC) ] Gyulassy 47

48 Outline 1. Overview of 3 convergent lines of evidence 2. Bulk Collective Flow and the QCD Equation of State 3. Parton Diagnostics: Jet Quenching 4. The D+Au Null Control 5. Conclusion: The QGP is found Gyulassy 48

49 The UN-Quenched Prediction for da (for x>0.01) is confirmed! STAR D+Au Au+Au Final PHOBOS AA quench must be due to final state interactions: Jet Quenching CIPANP 5/21/03 PHENIX, STAR, PHOBOS, BRAHMS Phys.Rev.Lett Lett.91 (2003) Gyulassy 49

50 d+au: two-particle correlations STAR: Phys.Rev.Lett Lett.91:072304,2003 no normalization to underlying event Check mate! The NULL da Quench prediction is seen in full strength central : back-to-back top 20% Correlations, FTPCE multiplicity as in p+p. underlying event grows: p+p < d+au minbias < d+au central near-side: correlation strength and width similar away-side: d+au peak broadens but little centrality dependence Unquenched back-to-back jets are observed in central d+au! From P. Jacobs for STAR Gyulassy 50

51 Outline 1. Overview of 3 convergent lines of evidence 2. Bulk Collective Flow and the QCD Equation of State 3. Parton Diagnostics: Jet Quenching 4. The D+Au Null Control 5. Conclusion: The QGP is found Gyulassy 51

52 Four independent calibrations of Initial QGP density 1. Bjorken Backward extrapolation E /N = 0.5 GeV, dn / dy= 1000, T ετ ( ) 100ε = 15 GeV / fm π τ = 1/p = 0.2 fm/c, V = (0.2 fm) π R = 30 fm ε = 500 Gev / 30 fm = 100ε 3 Bj Hydrodynamic initial condition needed for v 2 (p T ) π 3 3. Jet Tomography: dn g /dy = Gluon saturation p T <Q s predicted dn g /dy = 1000 at Q sat = 1 GeV at y=0 ε > 2ε = 500 Gev /30 fm = 100ε 3 Hydro Bj 0 εjets εbj 100ε0 KHH TS HN GLV WW MB McV EKRT Gyulassy 52

53 My 3 Part Definition of a QGP is satisfied 1. A form of matter (many body dynamical system) with a unique set of Bulk (collective) Elliptic Flow phenomena and partonic diagnostics Jet Quenching 2. which are calculable in the deconfined LatticeQCD (Colored) quark-gluon basis of QCD pqcd 3. And which can be turned on or off via Control experiments N part and Au->D Bonus: Softenning of the QGP EOS observed Gyulassy 53

54 The END of searching for QGP The BEGINNING of measuring its properties 12D Correlations Heavy Quarks Direct Photons Leptons Gyulassy 54

55 Experimental To Do List Y=+- 3 dau to test if x=0.001 QGP->CGC? C 2 (phi 1,phi 2, pt 1,pt 2, eta 1,eta 2, fl 1,fl 2, Mult, A,B, Ecm) Heavy Quark tomography [ Magdalena Djordjevic] Open Charm (enhancement?); J/Psi (suppression?) Charm Flow? [ Sotiria Batsouli ] Direct Photons thermometer and tagged direct photon -quark jets! Turn energy Ecm~ and A= exp. knobs Gyulassy 55

56 Theory To Do List HBT source E cm invariance? why No time-delay? E T /N E cm invariance, N part invariance? Dissipative effects on V 2 (pt)? V 2 (y) NON Bjorken boost invariant Baryon transport dynamics Thermalization, QGP Transport theory Gyulassy 56