Heavy Ions Collisions results and questions PART II

Heavy Ions Collisions (results and questions) PART II Anatoly Litvinenko litvin@moonhe. jinr. ru 1

Some estimations 2

Particle ratios and statistical models 3

Particle (hadrons) spectra A Iordanova (for the STAR Collaboration); J. Phys. G 35, p. 044008, (2008 4

elliptic flow hydrodynamics :

elliptic flow and space eccentricity

QUESTION II Is equilibrium state of hot and dense hadronic matter achieved? What is the conclusion about it from experiment? The strong indication that YES.

Observables and hadronic matter properties Some designations s. QGP for strongly-interacting Quark-Gluon Plasma Commonly accepted: QGP, p. QGP, w. QGP for weakly-interacting Quark-Gluon Plasma

KET – CQN Scaling Baryons Mesons Phys. Rev. Lett. 98, 162301 (2007) Quark-Like Degrees of Freedom Evident Roy A. Lacey, Stony Brook; Quark Matter 09, Knoxville, TN March 30 - April 4, 2009 10

Elliptic flow – energy dependance K. Aamodt et al. (ALICE Collaboration), PRL 105, 252302 (2010) 11

JET Quenching Jet: A localized collection of hadrons which come from a fragmenting parton Modification of Jet property in AA collisions, because of partons propagating in colored matter, which lose energy. One of the possible observable Was predicted in a lot of works. Some of them (not all) are: üJ. D. Bjorken (1982), Fermilab – PUB – 82 – 059 - THY. üM. Gyulassy and M. Palmer, Phys. Lett. , B 243, 432, 1990. üX. -N. Wang, M. Gyulassy and M. Palmer, Phys. Rev. , D 51, 3436, 1995. üR. Baier et al. , Phys. Lett. , B 243, 432, 1997. üR. Baier et al. , Nucl. Phys. , A 661, 205, 1999 12

High p. T (> ~2. 0 Ge. V/c) hadrons in NN h d h a c h Parton distribution functions b h Hard-scattering cross-section Fragmentation Function

High p. T (> ~2. 0 Ge. V/c) hadrons in AA Parton distribution functions h Hard-scattering cross-section A B Fragmentation Function + h Numbers of binary collisions Partonic Energy Loss

Suppression of high-pt hadrons. Qualitatively. Nuclear modification factor From naive picture is what we get divided by what we expect. 15

Nuclear modification factor Normalization on peripheral collisions 16

First data in first RHIC RUN Jet Quenching ! Great! But (see the next slide) 17

Nuclear modifications to hard scattering Large Cronin effect at SPS and ISR Suppression at RHIC Is the suppression due to the medium? (initial or final state effect? ) 18

Centrality dependance

Again Au+Au and d+Au Au+Au @ s. NN = 200 Ge. V d+Au @ s. NN = 200 Ge. V preliminary • Nice picture! Isn’t it? 20

The matter is so opaque that even a 20 Ge. V 0 is stopped. • Suppression is very strong (RAA=0. 2!) and flat up to 20 Ge. V/c • Common suppression for 0 and h; it is at partonic level • e > 15 Ge. V/fm 3; d. Ng/dy > 1100 21

JET Quenching at LHC . ALICE Collaboration, Physics Letters B 696 (2011) 30. 22

JET Quenching at LHC ALICE Collaboration, Physics Letters B 696 (2011) 30 23

The matter is so dense that even heavy quarks are stopped v Even heavy quark (charm) suffers substantial energy loss in the matter v The data provides a strong constraint on the energy loss models. v The data suggest large c-quark-medium cross section; evidence for strongly coupled QGP? (1) q_hat = 0 Ge. V 2/fm (4) d. Ng / dy = 1000 (2) q_hat = 4 Ge. V 2/fm (3) q_hat = 14 Ge. V 2/fm 24

If there any other observables for Jet Quenching? Yes! Back to Back Jets correlation. Near side jet Away side jet Trigger particle Associated particles Correlation of trigger particles 4<p. T<6. 5 Ge. V with associated particles 2<p. T, trig 25

Back to Back Jets correlation. Dependence from reaction plane. Out-of-plane In-plane Out-of-plane 26

Jet tomography STAR Preliminry 20 -60% Out-plane Back-to-back suppression depends on the reaction plane orientation energy loss dependence on the path length! In-plane 27

The matter is so dense that it modifies the shape of jets • The shapes of jets are modified by the matter. – Mach cone? – Cerenkov? • Can the properties of the matter be measured from the shape? – Sound velocity – Di-electric constant • Di-jet tomography is a powerful tool to probe the matter 28

Resonances melting (Debye scrinig) 29

One more results from lattice QCD heavy-quark screening mass -- suppression In EM plasma it is well known Debye screening 30

The matter is so dense that it melts(? ) J/y (and regenerates it ? ) d. Au mm 200 Ge. V/c Au. Au mm 200 Ge. V/c Cu. Cu mm 200 Ge. V/c Au. Au ee 200 Ge. V/c Cu. Cu ee 200 Ge. V/c v J/y’s are clearly suppressed beyond the cold nuclear matter effect v The preliminary data are consistent with the predicted suppression + regeneration at the energy density of RHIC collisions. v Can be tested by v 2(J/y)? 31

The matter is so dense that it melts Y. QM’ 11

direct photons • T 0 max ~ 500 -600 Me. V !? T 0 ave ~ 300 -400 Me. V !? 33

Summary o RHIC has produced a strongly interacting, partonic state of dense matter 34

Summary o The matter is so dense that even heavy quarks are stopped (1) q_hat = 0 Ge. V 2/fm (4) d. Ng / dy = 1000 (2) q_hat = 4 Ge. V 2/fm (3) q_hat = 14 Ge. V 2/fm 35

Summary o The matter is so strongly coupled that even heavy quarks flow 36

Summary o The matter is so dense that it melts(? ) J/y (and regenerates it ? ) 37

Summary o The matter modifies jets 38

Put the results together The matter is dense The matter is strongly coupled e > 15 Ge. V/fm 3 d. Ng/dy > 1100 Tave = 300 - 400 Me. V (? ) PHENIX preliminary The matter modifies jets The matter may melt but regenerate J/y’s 39 The matter is hot

Backup slides 40

CGC

CGC

CGC

Modeling the Source • Interaction region Assembly of classical boson emitting sources in space-time region • The source S(x, p) is the probability boson with p is emitted from x Determines single-particle momentum spectrum E d 3 N/dp 3 = d 4 x S(x, p) Determines the HBT two-particle correlation function C(K, q) ~ 1 + | d 4 x S(x, K) exp(iq·x) | 2/| d 4 x S(x, K) |2 where K = ½(p 1 + p 2) = (KT, KL), q = p 1 – p 2 The LCMS frame is used (KL = 0) • In the hydrodynamics-based parameterizations: assume something about the source S(x, p) Gaussian particle density distribution Linear flow (rapidity or velocity) profile January 6, 2002 RHIC/INT Winter Workshopproper 2002 Instantaneous freeze-out at constant time (“sharp”) 45

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Why the collisons of heavy nuclei is interesting? Let us see on the space – time picture of collision pre-collision QGP (? ) and parton production hadron reinteraction hadron production QCD phase diagram 49

The QGP in the early universe 50

What kind of transition is predicted by lattice QCD 51

Dependence on pseudorapidity of charged hadron S. S. Adler et al. , Phys. Rev. C 71, 034908 (2005) 52

Theoretical explanation Estimation from data Comparison to model calculations with and without parton energy loss: Numerical values range from ~ 0. 1 Ge. V / fm (Bjorken, elastic scattering of partons) ~several Ge. V / fm (BDMPS, nonlinear interactions of gluons) Too many approaches. We need additional data! 53

Initial state effects (test experiment d+Au) Suppression in central Au+Au due to final-state effects 54

Binary scaling. Is it work? 55

How about suppression for protons? New Close to nuclear mod. factor, because no suppression for peripheral coll. 56

Jets composition as measured by STAR Kirill Filimonov, QM’ 04 57

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Binary scaling. Is it work? Au+Au 200 Ge. V/A: 10% most central collisions ( p. QCD x Ncoll) / background Vogelsang/CTEQ 6 Preliminary ( p. QCD x Ncoll) / ( background x Ncoll) [w/ the real suppression] [if there were no suppression] [ ]measured / [ ]background = p. T (Ge. V/c) measured/ background 59

Theoretical explanation Comparison to model calculations with and without parton energy loss: Numerical values range from ~ 0. 1 Ge. V / fm (Bjorken, elastic scattering of partons) ~several Ge. V / fm (BDMPS, nonlinear interactions of gluons) Too many approaches. We need additional data! 60

If is there space for Color Glass Condensate or only Cronin Effect? May be. Look at the BRAMS DATA 61

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Observables and space time structure of Heavy ion collisions 63

Observables and space time structure of Heavy ion collisions v. Production of hard particles: § jets § heavy quarks § direct photons v. Calculable with the tools of perturbative QCD 64

Observables and space time structure of Heavy ion collisions v. Production of semi-hard particles: § gluons, light quarks v relatively small momentum: v make up for most of the multilplicity 65

Observables and space time structure of Heavy ion collisions v. Thermalization §experiment suggest a fast thermalization (remember elliptic flow) §but this is still not undestood from QCD 66

Observables and space time structure of Heavy ion collisions v. Quark gluon plasma 67

Observables and space time structure of Heavy ion collisions v. Hot hadron gas 68

Particle ratio and statistical models v. One assumes that particles are produced by a thermalized system with temperature T and baryon chemical potential v. The number of particles of mass m per unit volume is : These models reproduce the ratios of particle yields with only two parameters 69

One more observable. Particle ratios N/ ratio shows baryons enhanced for p. T < 5 Ge. V/c 70