Bulletin of the American Physical Society
2008 APS April Meeting and HEDP/HEDLA Meeting
Volume 53, Number 5
Friday–Tuesday, April 11–15, 2008; St. Louis, Missouri
Session 16HE: Quark-Gluon Plasmas |
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Sponsoring Units: HEDP HEDLA Chair: Barbara Jacak, State University of New York at Stony Brook Room: Hyatt Regency St. Louis Riverfront (formerly Adam's Mark Hotel), Promenade F |
Tuesday, April 15, 2008 10:50AM - 11:15AM |
16HE.00001: Introduction to strongly coupled quark-gluon plasma Invited Speaker: Quark-gluon plasma is a deconfined phase of QCD, at temperatures above $Tc\approx 170\, MeV$. Analysis of RHIC experiments and also lattice data have shown that it is not just a weakly coupled gas of quarks and gluons, as anticipated at large $T$. Strongly coupled plasmas can be studied via gauge-string duality known as AdS/CFT, which relates its properties to 5d black hole physics. I will mostly focus on another duality -- electric-magnetic one. It was recently realized that QGP near Tc has significant fraction of (color)-magnetically charged quasiparticles -- monopoles, and those Bose-condense below Tc. Molecular dynamics for plasma made of both electrically and magnetically charged particles revealed unusual properties: one of them significant increase of collision rate and decrease of diffusion and viscosity. At the end of the talk, results for transport coefficients from AdS/CFT and MD will be compared to empirical ones from RHIC data. [Preview Abstract] |
Tuesday, April 15, 2008 11:15AM - 11:40AM |
16HE.00002: Instabilities in non-Abelian plasmas Invited Speaker: Quark-gluon plasma, in spite of its non-Abelian dynamics, reveals some similarities to electromagnetic plasmas. In particular, there is a rich spectrum of instabilities which appear to be important to understand a fast equilibration of the quark-gluon plasma produced at the early stage of relativistic heavy-ion collisions. Experimental data suggest that such a plasma reaches equilibrium within 1 fm/c and inter- parton collisions seem to be ``slow.'' However, due to anisotropic momentum distribution, the parton system is unstable with respect to the chromo-magnetic plasma modes. These color instabilities, which are known in the electromagnetic plasmas as the Weibel instabilities, effectively isotropize the system and thus speed up the process of equilibration. [Preview Abstract] |
Tuesday, April 15, 2008 11:40AM - 12:05PM |
16HE.00003: Experimental study of properties of quark gluon plasma via heavy quarks and EM probes. Invited Speaker: Experimental results have established that very dense partonic matter is formed in Au+Au collisions at RHIC. At such high density, it is believed that quarks and gluons are no longer confined in hadrons, but become constitutes of a quark-gluon plasma (QGP). Heavy quark bound state (J/Psi), heavy quarks (charm and bottom), and EM probes (photons and dileptons) are best probes of the properties of the dense matter formed at RHIC. The suppression of J/Psi can probe the strength of the color screening in the matter. Observation of large energy loss and flow of heavy quarks suggests that the viscosity to the entropy ratio of the matter is close to its quantum lower bound. Production of photons and dileptons provide information deep inside of the matter. I will review recent experimental results of these measurements. [Preview Abstract] |
Tuesday, April 15, 2008 12:05PM - 12:30PM |
16HE.00004: Experimental study of collective motion in the quark gluon plasma Invited Speaker: Collective phenomena have been studied to investigate a property of Quark Gluon Plasma in high-energy heavy-ion collisions at AGS, SPS and RHIC experiments. Whether the origin of elliptic and/or radial collective expansions is given in a partonic or a hadronic phase during the collisons is a key question for the experimetal observables to be sensitive to the QGP or not. The number of quark scaling in the observed elliptic flow parameter v2 is one of intuitive evidences for the existence of the quark phase before the hadronization. The radial and elliptic flow of heavy quarks would also favour the strong interacting plasma phase. The modification of the near- and away-side jet shape and its relation to the elliptic anisotropy could prove the property of the matter in the phase. Experimental measurements especially on the collective motion of the high density and temperature matter created in high-enegy heavy-ion collisions will be presented and discussed. [Preview Abstract] |
Tuesday, April 15, 2008 12:30PM - 2:00PM |
16HE.00005: LUNCH BREAK |
Tuesday, April 15, 2008 2:00PM - 2:25PM |
16HE.00006: Probing the QCD Plasma with High Energy Jets Invited Speaker: QCD jets - the collimated spray of hadronic fragments from hard-scattered quarks and gluons - are a ubiquitous feature of high energy collisions. Heavy ion experiments at colliders put jets to a new use, utilizing partonic energy loss and the resulting modification of jet fragmentation as a sensitive, penetrating probe of the QCD plasma. The initial RHIC discovery of jet quenching, via the suppression of high pT hadron yields and di-hadron correlations, has been followed by more detailed observations of its flavor dependence and the response of the medium to partonic energy loss. I will review recent experimental progress in this area, and the quantitative understanding of the QCD plasma that is emerging. I will also discuss new opportunities for such measurements at the LHC and upgraded RHIC. [Preview Abstract] |
Tuesday, April 15, 2008 2:25PM - 2:50PM |
16HE.00007: Modeling strongly coupled quark gluon plasmas: hydro vs transport vs general relativity Invited Speaker: The discovery of near perfect fluid flow and very high jet opacity in nuclear collisions at 200 AGeV at RHIC/BNL have challenged traditional weak coupling perturbative QCD modeling of quark gluon plasmas. A critical assessment of current theoretical uncertainties facing competing approaches based on relativistic hydrodynamics, quasi-parton transport dynamics, and novel string theory inspired general relativity modeling will be presented. Special focus will be on identified (charm and bottom) heavy quark jets that will serve as powerful probes in upcoming RHIC and LHC experiments to better constrain the initial conditions as well as energy loss mechanisms leading to rapid equilibration in ultra-relativistic nuclear collisions. [Preview Abstract] |
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