Zhangbu Xu (Brookhaven National Lab) Free Quarks Constituent Quark Scaling of Flow Heavy Quark Thermalization Color Screening of Heavy Quarkonia Excited Vacuum Novel symmetries in QCD Dileptons as tool to systematically study Chiral Symmetry Restoration (Super-)Statistical Fluctuation in particle production Initial state of gluonic matter in nuclear collisions Search for Critical Point Recent RHIC Heavy-Ion Results

2 STAR Preliminary

3 Quark Matter 1995

4 NCQ Scaling STAR, arXiv: [nucl-ex] PHENIX, PRL 99, (2007) d(p+n) : n q = 2 x 3 3 He(2p+n) : n q = 3 x 3  Number of constituent quark scaling holds well for v 2 of 3 He.

5 Beam Energy and Species Many measurements show impressive scaling Many others show deviations: PID v 2 by ALICE U+U 0-2% PID v 2 by PHENIX Different pt ranges and centralities S.S. Shi, QM2012 Sakaguchi, S.L. Huang, QM2012

6 Flow of Heavy Quarks First measurement of directly reconstructed Charmed hadron radial flow at RHIC Elliptic flow of Electrons from heavy-flavor hadrons Different flow methods: large flow at low pt Jet contribution at high pt Dong, Wei, Tlusty QM2012

7 Integrated J/  yield N part dependence of J/  R AA : less suppression at LHC compared to at RHIC in central collisions interplay between CNM, color screening and ccbar recombination consistent with more significant contribution from ccbar recombination at LHC energies ALICE: Arnaldi, Arsene, Safarik, Scomparin PHENIX: PRC84(2001)054912

8 J/  p T dependence in A+A CMS: Mironov, Moon, Roland ALICE: Arnaldi, Safarik, Scomparin, Yang STAR: arXiv: , Trzeciak, XiePHENIX: PRL98(2007) J/  R AA decreases from low to high p T at LHC. J/  R AA increases from low to high p T at RHIC. At high p T, J/  more suppressed at LHC. Models incorporating color screening andrecombination can consistently describe the J/  suppression pattern and flow measurements.

9 Suppression without flow RHIC: large suppression, zero flow LHC: less suppression, hints of flow Color Screening and quark coalescence STAR Preliminary

10  Suppression in A+A  (1s) suppression magnitude consistent with excited states suppression.  (2S) strongly suppressed,  (3S) completely melted. Last piece of convincing evidence: color screening features of hot, dense medium in light of RHIC and LHC precise quarkonium measurements. STAR: Dong, Trzeciak, Xie (QM2012) CMS: arXiv: , Mironov, Rangel, Roland

11 Novel Symmetries Local Parity Violation Chiral Symmetry STAR, PRL 103, Crucial to verify if parity violation is the correct explanation U+U collisions: collisions with more v 2 and less B field than Au+Au

12 Beam energy scan From 2.76 TeV to 7.7 GeV, changes start to show from the peripheral collisions. (Wang, QM2012) ALICE, arXiv:

13 A dedicated trigger selected events with 0-1% spectator neutrons. With the magnetic field suppressed, the charge separation signal disappears (while v 2 is still ~ 2.5%). Chiral Magnetic in U+U The difference between OS and SS is still there in U+U, with similar magnitudes. Consider OS-SS to be the signal 0-5% 70-80% 20-40% STAR Preliminary (Wang, QM2012)

14 Electric Quadrupole Y. Burnier, D. E. Kharzeev, J. Liao and H-U Yee, Phys. Rev. Lett. 107, (2011) Wang, QM2012 Chiral Magnetic Wave

15 Energy dependence of di-electron spectra PHENIX HBD results at 200 GeV : consistent with previous publication in 20-92% centrality. STAR results: systematically study the di-electron continuum from 19.6, 39, 62.4 and 200 GeV. Observe enhancement above cocktails in low mass range (~0.5 GeV/c 2 ) 20-40% PHENIX: Atomssa, TserruyaSTAR: Dong, Geurts, Huang, Huck

16 p T (GeV/c) Direct photon spectra and elliptic flow  Low p T direct photon elliptic flow measurement could provide direct constraints on QGP dynamics (η/s, T, t 0 …).  Excess of direct photon yield over p+p: T eff =221 ± 19 ± 19 MeV in 0-20% Au+Au; substantial positive v 2 observed at p T <4 GeV/c.  Di-lepton v 2 versus p T & M ll : probe the properties of the medium from hadron-gas dominated to QGP dominated. (R. Chatterjee, D. K. Srivastava, U. Heinz, C. Gale, PRC75(2007)054909) PHENIX, arXiv: PHENIX: PRL104 (2010) Ruan, QM2012

17 Di-electron v 2 at 200 GeV Au+Au Cocktail simulation is consistent with the measured di-electron v 2 at M ee <1.1 GeV/c2. Need a factor of two more data to be sensitive to hardon gas and QGP contribution, in addition to independent measurements to disentangle ccbar correlation contribution R. Chatterjee, D. K. Srivastava, U. Heinz, C. Gale, PRC75(2007)054909) STAR: Cui, Geurts, Huang QM2012

18 Quantify the Enhancements Temperature dependence of rho spectral function 1.Beam energy range where final state is similar 2.Initial state and temperature evolution different 3.Density dependence by Azimuthal dependence (v 2 ) 4.Use centrality dependence as another knob

19 STAR: Cui, Dong, Geurts, Huang, Huck A tool to study Chiral Symmetry Restoration NA60, Eur.Phys.J.C59(2009)607 CERES: Eur.Phys.J.C41(2005)475 Ruan, QM2012

20 Pillars of Discoveries in QGP physics Horowitz,

21 Cold QCD matter – the initial state at RHIC  RHIC may provide unique access to the onset of saturation  2000—2008: yields  2008—: mono-jet  2009—: statistics/fluctuation pp peripheral dAucentral dAu STAR preliminary PHENIX, PRL107

22 Counting (Glittering) PHENIX PRC 78 Tribedy, Venugopalan PLB710 Gelis, Lappi, McLerran, NPA 828 (2009)

23 Where is the QCD critical point?  A landmark on the QCD phase diagram

24 Thermodynamic properties of hot QCD state A thermodynamic state A thermodynamic state is specified by a set of values of all the thermodynamic parameters necessary for the description of the system. --- statistical mechanics by K. Huang Temperature (T), chemical potential ( , pressure(P), viscosity (  ) … 1.Chemical/thermal Equilibrium at certain stage of the evolution 2.At the predicted QCD phase boundary 3.persistent from SPS to RHIC 4.Temperature decreases at AGS and SIS A. Andronic et al., NPA 837 (2010) 65

25 Predictable Production Rate Why is it so predictable? T=164MeV? + - A. Andronic, P. Braun-Munzinger, J. Stachel, and H. Stocker, Phys.Lett.B697: ,2011

26 Directed Flow of Protons Directed flow (v 1 ) slope: sensitive to 1 st order phase transition. Proton v 1 slope changes sign from + to – between 7.7 and 11.5 GeV and remains small but negative up to 200 GeV. v 1 slopes for other particles are all negative. “net-proton” v 1 slope shows a minimum around GeV. AMPT/UrQMD models cannot explain data. 26 (GeV) Pandit, Dong (STAR), QM2012

27 Higher Moments of Net-protons Net-proton/Net-charge/Net- kaon X.F. Luo, L.Z. Chen for STAR, QM2012

28 Negative Binomials fit all data Net charge Net kaon

29 Negative-Binomial Distribution vs. Tsallis generating function: average and variance: k = - N binomial distribution k =  Poisson distribution Aguiar, Kodama, PA320, 2003 Tsallis entropy: Non extensivity: “Partition function”:

30 Spectra by same statistics Are Heavy-Ion collisions governed by a set of generic statistic rules, which also exist in other complex systems? What does this physics tell us about statistics in complex systems. How do we use the existing tools to extract information beyond “normal” statistics?

31 Aims and scope To bring together scientists who have made contributions to Tsallis entropy and those who study complex systems. In physics, the Tsallis entropy is a generalization of the standard Boltzmann-Gibbs entropy. It was introduced in 1988 by Constantino Tsallis as a basis for generalizing the standard statistical mechanics. In the scientific literature, the physical relevance of the Tsallis entropy was occasionally debated. However, from the years 2000 on, an increasingly wide spectrum of natural, artificial and social complex systems have been identified which confirm the predictions and consequences that are derived from this nonadditive entropy, such as nonextensive statistical mechanics, which generalizes the Boltzmann-Gibbs theory. Among the various experimental verifications and applications presently available in the literature, the following ones deserve a special mention: - The distribution characterizing the motion of cold atoms in dissipative optical lattices, predicted in 2003 and observed in The fluctuations of the magnetic field in the solar wind enabled the calculation of the q-triplet (or Tsallis triplet). - Spin glass relaxation. - Trapped ion interacting with a classical buffer gas. - High energy collisional experiments at LHC/CERN (CMS, ATLAS and ALICE detectors) and RHIC/Brookhaven (STAR and PHENIX detectors). Among the various available theoretical results which clarify the physical conditions under which Tsallis entropy and associated statistics apply, the following ones can be selected: - Anomalous diffusion. - Uniqueness theorem. - Sensitivity to initial conditions and entropy production at the edge of chaos. - Probability sets which make the nonadditive Tsallis entropy to be extensive in the thermodynamical sense. - Strongly quantum entangled systems and thermodynamics. - Thermostatistics of overdamped motion of interacting particles. - Nonlinear generalizations of the Schroedinger, Klein-Gordon and Dirac equations.

32 Understanding Symmetry and DOF  RHIC is the best facility to study novel symmetries and critical point: flexible machine to change conditions beam species (magnetic field), BES (turn on/off QGP) Large Acceptance (good for both LPV and chiral symmetry) Excellent lepton PID (both electrons and muons at midrapidity, who else has that!)  Since the beginning of physics, symmetry considerations have provided us with an extremely powerful and useful tool in our effort to understand nature. Gradually they have become the backbone of our theoretical formulation of physical laws. — Tsung-Dao Lee Particle Physics and an Introduction to Field Theory (1981), 177  LPV: beam energy: deconfinement, chiral symmetry Beam species: magnetic field  Medium effect on vector mesons (chiral symmetry, resonant states): beam energy; Spectra and v 2 vs M l+l-  HFT+MTD+VTX upgrade First glimpse of dilepton spectra around  0 and 1<M<3GeV Heavy-flavor flow  Beyond 2017 Phase II BES sPHENIX Detailed studies of DOF 还