Results from the Relativistic Heavy Ion Collider

Müller, Berndt; Nagle, J. L.

doi:10.1146/annurev.nucl.56.080805.140556

“…This observation supports the underlying assumption of Ref. [5], linking the center domain walls to phenomena observed at RHIC [28] and the LHC [6][7][8].…”

Section: Resultssupporting

confidence: 86%

Visualizations of coherent center domains in local Polyakov loops

Stokes

¹

,

Kamleh

²

,

Leinweber

³

2014

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Quantum Chromodynamics exhibits a hadronic confined phase at low to moderate temperatures and, at a critical temperature T C , undergoes a transition to a deconfined phase known as the quark-gluon plasma. The nature of this deconfinement phase transition is probed through visualisations of the Polyakov loop, a gauge independent order parameter. We produce visualisations that provide novel insights into the structure and evolution of center clusters. Using the HMC algorithm the percolation during the deconfinement transition is observed. Using 3D rendering of the phase and magnitude of the Polyakov loop, the fractal structure and correlations are examined. The evolution of the center clusters as the gauge fields thermalise from below the critical temperature to above it are also exposed. We observe deconfinement proceeding through a competition for the dominance of a particular center phase. We use stout-link smearing to remove small-scale noise in order to observe the large-scale evolution of the center clusters. A correlation between the magnitude of the Polyakov loop and the proximity of its phase to one of the center phases of SU (3) is evident in the visualisations.

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“…In addition to theoretical efforts, the deconfinement transition and the properties of hot, strongly-interacting matter are also studied experimentally in heavy-ion collisions [860,861]. A significant part of the extensive experimental heavy-ion program is dedicated to measuring quarkonium yields since Matsui and Satz suggested that quarkonium suppression could be a signature of deconfinement [862].…”

Section: Quarkonia As a Probe Of Hot And Dense Mattermentioning

confidence: 99%

Heavy quarkonium: progress, puzzles, and opportunities

Brambilla¹,

Eidelman²,

Heltsley³

et al. 2011

Advances in the Physics of Particles and Nuclei

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A golden age for heavy quarkonium physics dawned a decade ago, initiated by the confluence of exciting advances in quantum chromodynamics (QCD) and an explosion of related experimental activity. The early years of this period were chronicled in the Quarkonium Working Group (QWG) CERN Yellow Report (YR) in 2004, which presented a comprehensive review of the status of the field at that time and provided specific recommendations for further progress. However, the broad spectrum of subsequent breakthroughs, surprises, and continuing puzzles could only be partially anticipated. Since the release of the YR, the BESII program concluded only to give birth to BESIII; the B-factories and CLEO-c flourished; quarkonium production and polarization measurements at HERA and the Tevatron matured; and heavy-ion collisions at RHIC have opened a window on the deconfinement regime. All these experiments leave legacies of quality, precision, and unsolved mysteries for quarkonium physics, and therefore beg for continuing investigations at BESIII, the LHC, RHIC, FAIR, the Super Flavor and/or Tau-Charm factories, JLab, the ILC, and beyond. The list of newly-found conventional states expanded to include hc(1P ), χc2(2P ), B + c , and η b (1S). In addition, the unexpected and still-fascinating X(3872) has been joined by * Editors † Section coordinators ‡ Corresponding author: bkh2@cornell.edu more than a dozen other charmonium-and bottomonium-like "XY Z" states that appear to lie outside the quark model. Many of these still need experimental confirmation. The plethora of new states unleashed a flood of theoretical investigations into new forms of matter such as quark-gluon hybrids, mesonic molecules, and tetraquarks. Measurements of the spectroscopy, decays, production, and in-medium behavior of cc, bb, and bc bound states have been shown to validate some theoretical approaches to QCD and highlight lack of quantitative success for others. Lattice QCD has grown from a tool with computational possibilities to an industrialstrength effort now dependent more on insight and innovation than pure computational power. New effective field theories for the description of quarkonium in different regimes have been developed and brought to a high degree of sophistication, thus enabling precise and solid theoretical predictions. Many expected decays and transitions have either been measured with precision or for the first time, but the confusing patterns of decays, both above and below open-flavor thresholds, endure and have deepened. The intriguing details of quarkonium suppression in heavy-ion collisions that have emerged from RHIC have elevated the importance of separating hotand cold-nuclear-matter effects in quark-gluon plasma studies. This review systematically addresses all these matters and concludes by prioritizing directions for ongoing and future efforts.

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“…

We argue that the domain structure of deconfined QCD matter, which can be inferred from the properties of the Polyakov loop, can simultaneously explain the two most prominent experimentally verified features of the quark-gluon plasma, namely its large opacity as well as its near ideal fluid properties.One of the major achievements of the experimental program at the Relativistic Heavy Ion Collider (RHIC) is the creation of a novel state of hot and dense QCD matter dubbed the strongly interacting Quark-Gluon Plasma (sQGP) [1][2][3][4][5][6]. The characterization of the properties of the sQGP is based on three major discoveries: (1) the measurement of strong elliptic flow and the success of relativistic viscous hydrodynamics with a very small value of the shear viscosity η to entropy density s ratio close to the conjectured quantum lower bound [7] that argues for the near perfect liquid nature of the sQGP and a very short thermalization time of less than 1 fm/c, (2) the measurement of very strong suppression of highmomentum particles and rapid redistribution of the jet energy into the whole solid angle, which is indicative of the large opacity of the produced matter, and (3) the observed constituent quark number scaling law for the elliptic flow of identified hadrons as predicted by the parton recombination model [8][9][10][11] that provides the most direct evidence for the formation of hadrons from a deconfined system of interacting patrons.

…”

mentioning

confidence: 99%

Center Domains and their Phenomenological Consequences

Asakawa

¹

,

Bass

²

,

Müller

³

2013

Self Cite

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We argue that the domain structure of deconfined QCD matter, which can be inferred from the properties of the Polyakov loop, can simultaneously explain the two most prominent experimentally verified features of the quark-gluon plasma, namely its large opacity as well as its near ideal fluid properties.One of the major achievements of the experimental program at the Relativistic Heavy Ion Collider (RHIC) is the creation of a novel state of hot and dense QCD matter dubbed the strongly interacting Quark-Gluon Plasma (sQGP) [1][2][3][4][5][6]. The characterization of the properties of the sQGP is based on three major discoveries: (1) the measurement of strong elliptic flow and the success of relativistic viscous hydrodynamics with a very small value of the shear viscosity η to entropy density s ratio close to the conjectured quantum lower bound [7] that argues for the near perfect liquid nature of the sQGP and a very short thermalization time of less than 1 fm/c, (2) the measurement of very strong suppression of highmomentum particles and rapid redistribution of the jet energy into the whole solid angle, which is indicative of the large opacity of the produced matter, and (3) the observed constituent quark number scaling law for the elliptic flow of identified hadrons as predicted by the parton recombination model [8][9][10][11] that provides the most direct evidence for the formation of hadrons from a deconfined system of interacting patrons. All three discoveries have by now been confirmed in measurements of Pb+Pb collisions at the CERN Large Hadron Collider (LHC) [12].In this work we shall focus on the dynamical properties of the sQGP and shall present a picture in which the low specific viscosity and high color opacity can be understood in a consistent fashion. Most calculations of the jet energy-loss are based on perturbative QCD and are only sensitive to the gluon content of the matter, but do not distinguish between different microscopic structures related to quark confinement or chiral symmetry breaking. Lattice calculations are not yet able to give reliable results for transport properties of the sQGP that can provide clues about its structure. Holographic approaches to strongly coupled supersymmetric gauge theories have been used to model dynamical properties of the sQGP, but it remains unclear how well these gauge plasmas mirror the physics of the QGP.So far, very little attention has been paid to the nonperturbative structure of the gauge field configurations in the quark-gluon plasma and how it may affect the features observed in the experiments at RHIC and LHC. In particular, our focus here is on the Polyakov loop. We shall argue that the sQGP produced in relativistic heavy ion collisions has a domain structure based on the different minima of the Polyakov loop potential in the deconfined phase, and that this domain structure can be instrumental for generating the large opacity and small value of η/s seen in the sQGP.Two characteristic features distinguish the quarkgluon plasma from the hadron phase: r...

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Results from the Relativistic Heavy Ion Collider

Cited by 246 publications

References 213 publications

Visualizations of coherent center domains in local Polyakov loops

Visualizations of coherent center domains in local Polyakov loops

Heavy quarkonium: progress, puzzles, and opportunities

Center Domains and their Phenomenological Consequences

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