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MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 1/54 Experimental Results from RHIC: QGP or what? M. J. Tannenbaum Brookhaven National Laboratory Upton, NY.

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Presentation on theme: "MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 1/54 Experimental Results from RHIC: QGP or what? M. J. Tannenbaum Brookhaven National Laboratory Upton, NY."— Presentation transcript:

1 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 1/54 Experimental Results from RHIC: QGP or what? M. J. Tannenbaum Brookhaven National Laboratory Upton, NY USA RHIC&AGS Users Meeting June, 2005 See nucl-ex/ PHENIX nucl-ex/ BRAHMS nucl-ex/ PHOBOS nucl-ex/ STAR

2 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 2/54 Warning Beware of Theory Curves on Experimental Data

3 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 3/54 Original observation of Drell-Yan pairs: “massive muon pairs in hadron collisions”

4 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 4/54 The Measurement

5 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 5/54 Theorists at Work

6 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 6/54 The Measurement with “theory” curve

7 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 7/54 The Truth-the clarity of Hindsight NA50 PLB 477, 28 (2000)

8 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 8/54 RHIC: Experiments STAR

9 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 9/54 Example of a central Au+Au event at  s nn =200 GeV dn ch /d   =0 = 700 for central Au+Au collisions cf. 2.5 for p-p collisions

10 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 10/54 Run Year Species s 1/2 [GeV ]  Ldt N tot p-p Equivalent Data Size Au+Au  b -1 10M 0.04 pb -1 3 TB /2002 Au+Au  b M 1.0 pb TB p+p pb G 0.15 pb TB /2003 d+Au nb G 1.1 pb TB p+p pb G 0.35 pb TB /2004 Au+Au  b G 10.0 pb TB Au+Au 62 9  b -1 58M 0.36 pb TB /2005 Cu+Cu nb G 12.5 pb -1 Cu+Cu  b M 0.76 pb -1 p+p 200 pb -1 pb -1 p+p 405 pb -1 pb -1 Run-1 to Run-5 Capsule History

11 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 11/54 Energy Density

12 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 12/54 Spacetime evolution is important  =1/

13 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 13/54 N charged, E T exhibit(&could determine) the Nuclear Geometry Define centrality classes: ZDC vs BBC Extract N participants: Glauber model b N ch ETET E ZDC Q BBC N ch PHENIX ETET

14 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 14/54 Is the energy density high enough? PRL87, (2001) R2R2 2c   Colliding system expands: Energy  to beam direction per unit velocity || to beam   4.6 GeV/fm 3 (130 GeV Au+Au) 5.5 GeV/fm 3 (200 GeV Au+Au) well above predicted transition! EMCal measures  Bj

15 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 15/54 Particle Production

16 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 16/54 Semi-Inclusive soft particle spectra D.d'Enterria &D. Peressounko nucl-th/ Au+Au central (b < 2.6 fm) Hydro QCD :  < K < p 25% (  ) to 40% (p) increase from peripheral to central

17 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 17/54 p < 2 p=2 p > 2 dN/x dx x = Inclusive p T spectra are Gamma Distributions

18 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 18/54 Increase of with centrality--radial flow p T ~  T  T m Strong radial collective flow built-up at freeze-out:  0.6

19 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 19/54 Particle ratios---inclusive and at high p T inclusive vs centrality-nothing much Au+Au  s NN =200 GeV dramatic with centrality vs p T

20 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 20/54 Low p T (inclusive) ratios consistent with ``Thermal’’--but so are pp and e + e - Assume all distrib. described by one T and one  : 1 ratio (e.g. p/p) determines  /T 2 nd ratio (e.g. K/pi) provides T, . Then predict all other hadronic yields and ratios n.b strangeness not suppressed  s =1 dN ~ e - (E-  )/T d 3 p p/p ~ e – (E+  )/T /e –(E-  )/T = e - 2  /T

21 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 21/54 Final-state analysis suggests RHIC reaches the phase boundary Hadron resonance ideal gas (M. Kaneta and N. Xu, nucl-ex/ & QM02) –T CH = 175 ± 10 MeV –  B = 40 ± 10 MeV /N ~ 1 GeV (J. Cleymans and K. Redlich, Phys.Rev.C, 60, , 1999 ) Lattice results Neutron STAR Phase Diagram from Thermal Fit of particle ratios---``chemical” Where is the QGP critical point?

22 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 22/54 Are there fluctuations beyond random? Are there fluctuations beyond random? Event-by-event average p T (M pT ) is closely related to E T compare Data to Mixed events for random. deviation expressed as: Fp T =  MpTdata /  MpTmixed -1 ~ few % due to jets see PRL 93, (04)

23 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 23/54 What e-by-e tells you that you don’t learn from the inclusive average e-by-e averages separate classes of events with different average properties, for instance 17% of events could be all kaons, and 83% all pions---see C. Roland QM2004, e-by-e K/  consistent with random. A nice example I like is by R. Korus, et al, PRC 64, (2004): The temperature T~1/b varies event by event with  T  and  T.

24 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 24/54 Assuming all fluctuations are from  T /  T  Very small and relatively constant with  s NN T/TT/T CERES tabulation H.Sako, et al, JPG 30, S1371 (04) Where is the critical point?

25 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 25/54 Anisotropic (Elliptic) Transverse Flow--an Interesting complication in AA collisions Perform a Fourier decomposition of the momentum space particle distributions in the x-y plane v 2 is the 2nd harmonic Fourier coefficient of the distribution of particles with respect to the reaction plane pxpx pypy spatial anisotropy  momentum anisotropy x y z Reaction Plane

26 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 26/54 Centrality and p T dependence of v 2 STAR 200 GeV (preliminary) STAR130 GeV PRL 86, (2001) 402 more central  Hydro predictions follows eccentricity of almond saturates for pT >2 GeV/c unidentified charged hadrons

27 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 27/54 Detailed comparison to hydrodynamics with identified particles--The perfect fluid (?) STAR-PRC-nucl-ex/ D.Teaney, PRC68, (2003)

28 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 28/54 Hard-Scattering: Jet (  0 ) Suppression

29 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 29/54 RHIC pp spectra  s=200 GeV nicely illustrate hard scattering phenomenology 00 Good agreement with NLO pQCD this is no surprise for `old timers’ (like me) since single particle inclusive spectra were what proved QCD in the late 1970’s before jets. Reference for A+A and p+A spectra  0 measurement in same experiment allows us the study of nuclear effect with less systematic uncertainties. PHENIX (p+p) PRL 91, (2003) Hard Scattering p-p Thermally- shaped Soft Production

30 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 30/54  -A DIS at AGS (1973)--Hard-Scattering is pointlike  -A DIS at AGS (1973)--Hard-Scattering is pointlike

31 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 31/54 High p T in A+B collisions---T AB Scaling view along beam axis For point-like processes, the cross section in p+A or A+B collisions compared to p-p is simply proportional to the relative number of possible pointlike encounters A for p+A, AB for A+B for the total rate T AB the overlap integral of the nuclear profile functions, as a function of impact parameter b looking down

32 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 32/54 What really Happens for p+A: R A > 1! The anomalous nuclear enhancement a.k.a. the Cronin effect-- due to multiple scattering of initial nucleons (or constituents) Known since 1975 that yields increase as A ,  > 1 J.W. Cronin et al., Phys. Rev. D11, 3105 (1975) D. Antreasyan et al., Phys. Rev. D19, 764 (1979)  =1.148  0.010

33 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 33/54 Same for A+A at  s NN = 17, 31 GeV Nuclear Modification Factor:

34 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 34/54 For Au+Au at RHIC--strong suppression ! Au+Au   0 X (peripheral) Au+Au   0 X (central) Peripheral data agree well with Strong suppression in p+p (data & pQCD) scaled by T AB (N coll -) central Au+Au collisions

35 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 35/54 R AA (  0 ) AuAu:pp 200GeV High p T Suppression flat from 3 to 10 GeV/c ! PRL 91, (2003) Binary scaling Participant scaling Factor 5 Large suppression in central AuAu - close to participant scaling at high P T Peripheral AuAu - consistent with N coll scaling (large systematic error)

36 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 36/54 Run-1: RHIC Headline News … January 2002 THE major discovery at RHIC (so far) PHENIX First observation of large suppression of high p T hadron yields ‘‘ Jet Quenching’’? == Quark Gluon Plasma? PHENIX PRL 88, (2002)

37 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 37/54 RHIC Run 2  s=200 GeV: Comprehensive  0 data vs centrality in Au+Au +  0 reference in p-p Au-Au nucl-ex/ Phys. Rev. Letters 91, (2003) Centrality PHENIX Collab. PRC 69, (2004) nucl-ex/ PHENIX

38 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 38/54 Suppression: Final State Effect? Hadronic absorption of fragments: Gallmeister, et al. PRC67,044905(2003) Fragments formed inside hadronic medium Parton recombination (up to moderate p T ) Fries, Muller, Nonaka, Bass nucl-th/ Lin & Ko, PRL89,202302(2002) Energy loss of partons in dense matter Gyulassy, Wang, Vitev, Baier, Wiedemann… See nucl-th/ for a review.

39 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 39/54 Alternative: Initial Effects Gluon Saturation (color glass condensate: CGC) Wave function of low x gluons overlap; the self-coupling gluons fuse, saturating the density of gluons in the initial state. (gets N ch right!) hep-ph/ ; D. Kharzeev, E. Levin, M. Nardi Multiple elastic scatterings (Cronin effect) Wang, Kopeliovich, Levai, Accardi Nuclear shadowing r/  gg  g D.Kharzeev et al., PLB 561 (2003) 93 Broaden p T

40 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 40/54 p p g q  q Direct Photons in Au+Au 200 GeV: follow T AB scaling from p-p for all centralities-no suppression Direct photon production in Au+Au (all centralities) consistent w/ “T AB - scaled” pQCD. Proves that initial state Au structure function is simply a superposition of p-p structure functions including g(x). Submitted to PRL nucl-ex/ outgoing Direct photons unaffected by QCD medium in Au+Au   0 suppression is medium effect

41 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 41/54 NLO-pQCD calculation Private communication with W.Vogelsang CTEQ6M PDF. direct photon + fragmentation photon Set Renormalization scale and factorization scale pT/2,pT,2pT The theory calculation shows a good agreement with our result Confirms use of theoretical result as Au+Au comparison Opens the way for measurement of gluon spin structure function from A LL (Subtraction) Direct-  measurement in  s=200 GeV p-p

42 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 42/54 d+Au: Control Experiment to prove the Au+Au discovery The “Color Glass Condensate” model predicts the suppression in both Au+Au and d+Au (due to the initial state effect). The d+Au experiment tells us that the observed hadron suppression at high p T central Au+A is a final state effect. This diagram also explains why we can’t measure jets directly in Au+Au central collisions: all nucleons participate so charged multiplicity is ~200 times larger than a p-p collision  300 GeV in standard jet cone. Au+Au d+Au = cold medium = hot and dense medium Initial State Effects Only Initial + Final State Effects

43 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 43/54 Cronin effect observed in d+Au at RHIC  s NN =200 GeV, confirms x is a good variable PHENIX preliminary  0 d+Au vs centrality for DNP2003

44 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 44/54 This leads to our second PRL cover, our first being the original Au+Au discovery

45 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 45/54 Theoretical Understanding? Both Au-Au suppression (I. Vitev and M. Gyulassy, hep-ph/ ) d-Au enhancement (I. Vitev, nucl-th/ ) understood in an approach that combines multiple scattering with absorption in a dense partonic medium  Our high p T probes have been calibrated and are now being used to explore the precise properties of the medium Au-Au d-Au See nucl-th/ for a review.

46 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 46/54 Suppression is a Final State Medium Effect Energy loss of partons in dense matter--A medium effect predicted in QCD---Energy loss by colored parton in medium composed of unscreened color charges by gluon bremsstrahlung--LPM radiation Gyulassy, Wang, Vitev, Baier, Wiedemann… See nucl-th/ for a review. Baier, Dokshitzer, Mueller, Peigne, Shiff, NPB483, 291(1997), PLB345, 277(1995), Baier hep-ph/ , From Vitev nucl-th/ :  Bj   =15 GeV/fm 3 =10 x larger unscreened color charge density than in a nucleon

47 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 47/54 Baier, et al: Screened Coulomb potential MJT:  2 plays role of t min...  = 0.5 GeV/c=1/0.4 fm

48 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 48/54 One Big Grape-but size of a nucleon  (1 - e -  r )/  r Rep. Prog. Phys. 63 (2000) fm1.6fm

49 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 49/54 Jet Physics …jets in AuAu “difficult”--but STAR-Jet event in pp  collision STAR Au+Au collision High p T particle p+p High p T particle Au+Au

50 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 50/54 STAR--Away jet is suppressed-- consistent with energy loss Select a ``trigger’’ particle 4


51 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 51/54 Implies that v 2 p T > 2 GeV/c is due to anisotropic energy loss Implies that v 2 p T > 2 GeV/c is due to anisotropic energy loss PHENIX Preliminary

52 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 52/54 Nobody believes that v 2 p T >2 GeV/c is entirely due to hydro pressure--perfect fluid (?) STAR-PRC-nucl-ex/ D.Teaney, PRC68, (2003)

53 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 53/54 Conclusions the nuclear matter produced in central Au+Au collisions at RHIC appears to be a nearly perfect quark-gluon "liquid" instead of behaving like a gas of free quarks and gluons. No signs of a rapid phase transition have been seen---consistent with latest ideas that transition is a cross-over at RHIC energies. The medium at RHIC is characterized by very high energy densities, density of unscreened color charges ten times that of a nucleon, large cross sections for the interaction between strongly interacting particles, strong collective flow which implies early thermalization. This state of matter is not describable in terms of ordinary color- neutral hadrons, because there is no known self-consistent theory of matter composed of ordinary hadrons at the measured densities.

54 MJT-RHIC&AGS Users June 2005M. J. Tannenbaum 54/54 But there is more Hydro totally fails for Bose-Einstein (Hanbury-Brown Twiss)(GGLP) correlations. In the range 2 < p T < 4.5 GeV/c protons are not suppressed. This has spawned a whole new idea called Recombination. J/Psi measurements in p-p collisions are consistent with total cross section measurements at lower  s, but Au+Au measurements are inconclusive so far--new results at Quark Matter 2005 in August. Test whether the LPM energy loss formalism is correct in detail? If so, can measure properties of medium Do charm quarks flow?...


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