Indian Academy of Sciences (India)
C P Singh
2000-04-01
Recent trends in the research of quark gluon plasma (QGP) are surveyed and the current experimental and theoretical status regarding the properties and signals of QGP is reported. We hope that the experiments commencing at relativistic heavy-ion collider (RHIC) in 2000 will provide a glimpse of the QGP formation.
Nayak, Tapan; Sarkar, Sourav
2014-01-01
At extremely high temperatures and densities, protons and neutrons may dissolve into a "soup" of quarks and gluons, called the Quark-Gluon Plasma (QGP). For a few microseconds, shortly after the Big Bang, the Universe was filled with the QGP matter. The search and study of Quark-Gluon Plasma (QGP) is one of the most fundamental research topics of our times. The QGP matter has been probed by colliding heavy ions at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory, New York and the Large Hadron Collider at CERN, Geneva. By colliding heavy-ions at a speed close to that of light, scientists aim to obtain - albeit over a tiny volume of the size of a nucleus and for an infinitesimally short instant - a QGP state. This QGP state can be observed by dedicated experiments, as it reverts to hadronic matter through expansion and cooling. This volume presents some of the current theoretical and experimental understandings in the field of QGP.
2016-01-01
This is the fifth volume in the series on the subject of quark-gluon plasma, a unique phase created in heavy-ion collisions at high energy. It contains review articles by the world experts on various aspects of quark-gluon plasma taking into account the advances driven by the latest experimental data collected at both the Relativistic Heavy-Ion Collider (RHIC) and the Large Hadron Collider (LHC). The articles are pedagogical and comprehensive which can be helpful for both new researchers entering the field as well as the experienced physicists working on the subject.
Hamieh, Salah; Letessier, Jean; Rafelski, Johann
2000-01-01
Lattice-QCD results provide an opportunity to model, and extrapolate to finite baryon density, the properties of the quark-gluon plasma (QGP). Upon fixing the scale of the thermal coupling constant and vacuum energy to the lattice data, the properties of resulting QGP equations of state (EoS) are developed. We show that the physical properties of the dense matter fireball formed in heavy ion collision experiments at CERN-SPS are well described by the QGP-EoS we presented. We also estimate the...
Equilibration in quark gluon plasma
Das, S. K.; Alam, J.; Mohanty, P.
2011-07-01
The hydrodynamic expansion rate of quark gluon plasma (QGP) is evaluated and compared with the scattering rate of quarks and gluons within the system. Partonic scattering rates evaluated within the ambit of perturbative Quantum Choromodynamics (pQCD) are found to be smaller than the expansion rate evaluated with ideal equation of state (EoS) for the QGP. This indicate that during the space-time evolution the system remains out of equilibrium. Enhancement of pQCD cross sections and a more realistic EoS keep the partons closer to the equilibrium.
Equilibration in Quark Gluon Plasma
Das, Santosh K.; Alam, Jan-e; Mohanty, Payal
2009-01-01
The hydrodynamic expansion rate of quark gluon plasma (QGP) is evaluated and compared with the scattering rate of quarks and gluons within the system. Partonic scattering rates evaluated within the ambit of perturbative Quantum Choromodynamics (pQCD) are found to be smaller than the expansion rate evaluated with ideal equation of state (EoS) for the QGP. This indicate that during the space-time evolution the system remains out of equilibrium. Enhancement of pQCD cross sections and a more real...
Equilibration in Quark Gluon Plasma
Das, Santosh K; Mohanty, Payal
2009-01-01
The hydrodynamic expansion rate of quark gluon plasma (QGP) is evaluated and compared with the scattering rate of quarks and gluons within the system. Partonic scattering rates evaluated within the ambit of perturbative Quantum Choromodynamics (pQCD) are found to be smaller than the expansion rate evaluated with ideal equation of state (EoS) for the QGP. This indicate that during the space-time evolution the system remains out of equilibrium. Enhancement of pQCD cross sections and a more realistic EoS keep the partons closer to the equilibrium.
Hamieh, Salah; Letessier, Jean; Rafelski, Johann
2000-12-01
Lattice quantum chromodynamics results provide an opportunity to model, and extrapolate to finite baryon density, the properties of the quark-gluon plasma (QGP). Upon fixing the scale of the thermal coupling constant and vacuum energy to the lattice data, the properties of resulting QGP equations of state (EoS) are developed. We show that the physical properties of the dense matter fireball formed in heavy ion collision experiments at CERN-SPS are well described by the QGP-EoS we presented. We also estimate the properties of the fireball formed in early stages of nuclear collision, and argue that QGP formation must be expected down to 40A GeV in central Pb-Pb interactions.
HUNTING THE QUARK GLUON PLASMA.
Energy Technology Data Exchange (ETDEWEB)
LUDLAM, T.; ARONSON, S.
2005-04-11
matter at extremely high density and temperature--a medium in which the predictions of QCD can be tested, and new phenomena explored, under conditions where the relevant degrees of freedom, over nuclear volumes, are expected to be those of quarks and gluons, rather than of hadrons. This is the realm of the quark gluon plasma, the predicted state of matter whose existence and properties are now being explored by the RHIC experiments.
Smilga, A V
1997-01-01
In this lecture, we give a brief review of what theorists now know, understand, or guess about static and kinetic properties of quark--gluon plasma. A particular attention is payed to the problem of physical observability, i.e. the physical meaningfulne ss of various characteristics of QGP discussed in the literature.
Baryon Ratios in Quark-Gluon Plasma
Institute of Scientific and Technical Information of China (English)
MA Zhong-Biao; MIAO Hong; GAO Chong-Shou
2003-01-01
A way to calculate ratios of baryon produced from quark gluon plasma in relativistic heavyion collisionsis presented. It is assumed that at the beginning of the hadronization there are diquarks and anti-diquarks in the quarkmatter. The number of three-quark states is distributed between the corresponding multiplets, and hadronic decays aretaken into account. The results are shown at last.
Strongly Coupled Quark Gluon Plasma (SCQGP)
Bannur, V M
2006-01-01
We propose that the reason for the non-ideal behavior seen in lattice simulation of quark gluon plasma (QGP) and relativistic heavy ion collisions (URHICs) experiments is that the QGP near T_c and above is strongly coupled plasma (SCP), i.e., strongly coupled quark gluon plasma (SCQGP). It is remarkable that the widely used equation of state (EoS) of SCP in QED (quantum electrodynamics) very nicely fits lattice results on all QGP systems, with proper modifications to include color degrees of freedom and running coupling constant. Results on pressure in pure gauge, 2-flavors and 3-flavors QGP, are all can be explained by treating QGP as SCQGP as demonstated here.Energy density and speed of sound are also presented for all three systems.
Colliding solitary waves in quark gluon plasmas
Rafiei, Azam; Javidan, Kurosh
2016-09-01
We study the head-on collision of propagating waves due to perturbations in quark gluon plasmas. We use the Massachusetts Institute of Technology bag model, hydrodynamics equation, and suitable equation of state for describing the time evolution of such localized waves. A nonlinear differential equation is derived for the propagation of small amplitude localized waves using the reductive perturbation method. We show that these waves are unstable and amplitude of the left-moving (right-moving) wave increases (decreases) after the collision, and so they reach the borders of a quark gluon plasma fireball with different amplitudes. Indeed we show that such arrangements are created because of the geometrical symmetries of the medium.
Energy Density in Quark-Gluon Plasma
Institute of Scientific and Technical Information of China (English)
马忠彪; 苗洪; 高崇寿
2003-01-01
We study the energy density in quark-gluon plasma. At the very high temperature, the quark matter is a hot and dense matter in the colour deconfinement condition, and quarks can coalescent diquarks. Energy density of this system is worked out and compared with the energy density in the other two kinds of situations. Possible energy density is about eo ≈ 2.4 GeV/fm3 according to our estimation for quark matter including diquarks,
Hadrons and Quark-Gluon Plasma
Letessier, Jean; Rafelski, Johann
2002-06-01
Before matter as we know it emerged, the universe was filled with the primordial state of hadronic matter called quark gluon plasma. This hot soup of quarks and gluon is effectively an inescapable consequence of our current knowledge about the fundamental hadronic interactions, quantum chromodynamics. This book covers the ongoing search to verify this prediction experimentally and discusses the physical properties of this novel form of matter.
On the quark-gluon plasma search
Hamieh, S. D.
2004-01-01
We report on the effect of the quantum statistics on the two-proton spin correlation (SC) in cold and thermal nuclear matter. We have found that two nucleons SC function can be well approximated by a guassian with correlations length $\\sigma\\sim1.2$ fm. We have proposed SC measurement on low protons energy as test of the quark-gluon plasma formation in relativistic heavy ions collisions.
Electromagnetic signals of quark gluon plasma
Indian Academy of Sciences (India)
Bikash Sinha
2000-04-01
Successive equilibration of quark degrees of freedom and its effects on electromagnetic signals of quark gluon plasma are discussed. The effects of the variation of vector meson masses and decay widths on photon production from hot strongly interacting matter formed after Pb + Pb and S + Au collisions at CERN SPS energies are considered. It has been shown that the present photon spectra measured by WA80 and WA98 Collaborations can not distinguish between the formation of quark matter and hadronic matter in the initial state.
Plasmons in Anisotropic Quark-Gluon Plasma
Carrington, Margaret E; Mrowczynski, Stanislaw
2014-01-01
Plasmons of quark-gluon plasma - gluon collective modes - are systematically studied. The plasma is, in general, non-equilibrium but homogeneous. We consider anisotropic momentum distributions of plasma constituents which are obtained from the isotropic one by stretching or squeezing in one direction. This leads to prolate or oblate distributions, respectively. We study all possible degrees of one dimensional deformation from the extremely prolate case, when the momentum distribution is infinitely elongated in one direction, to the extremely oblate distribution, which is infinitely squeezed in the same direction. In between these extremes we discuss arbitrarily prolate, weakly prolate, isotropic, weakly oblate and arbitrarily oblate distributions. For each case, the number of modes is determined using a Nyquist analysis and the complete spectrum of plasmons is found analytically if possible, and numerically when not. Unstable modes are shown to exist in all cases except that of isotropic plasma. We derive con...
Exploding Quark-Gluon Plasma Fireball
Hamieh, S; Rafelski, Johann; Hamieh, Salah; Letessier, Jean; Rafelski, Johann
2000-01-01
Lattice-QCD results provide an opportunity to model and extrapolate to finite baryon density the properties of the quark-gluon plasma (QGP). Upon fixing the scale of the thermal coupling constant and vacuum energy to the lattice data the properties of resulting QGP equations of state (EoS) are developed. An exploding dense matter fireball formed in heavy ion collision experiments at CERN-SPS is considered, and we show that its physical properties are well described by the QGP-EoS we presented. We quantitatively determine the conditions of sudden breakup of the fireball, and show that this instability point is consistent with with the hadronization condition derived from the hadronic particle production data. We further estimate the properties of the fireball as it is formed just after nuclear collision is completed and show that QGP formation must be expected down to 40$A$ GeV central Pb--Pb interactions.
Physics of the quark - gluon plasma
Energy Technology Data Exchange (ETDEWEB)
NONE
2001-09-01
This document gathers 31 contributions to the workshop on the physics of quark-gluon plasma that took place in Palaiseau in september 2001: 1) gamma production in heavy collisions, 2) BRAHMS, 3) experimental conference summary, 4) modelling relativistic nuclear collisions, 5) microscopic reaction dynamics at SPS and RHIC, 6) direct gamma and hard scattering at SPS, 7) soft physics at RHIC, 8) results from the STAR experiment, 9) quarkonia: experimental possibilities, 10) elliptic flow measurements with PHENIX, 11) charmonium production in p-A collisions, 12) anisotropic flow at the SPS and RHIC, 13) deciphering the space-time evolution of heavy ion collisions with correlation measurements, 14) 2-particle correlation at RHIC, 15) particle spectra at AGS, SPS and RHIC, 16) strangeness production in STAR, 17) strangeness production in Pb-Pb collisions at SPS, 18) heavy ion physics at CERN after 2000 and before LHC, 19) NEXUS guideline and theoretical consistency, 20) introduction to high p{sub T} physics at RHIC, 21) a novel quasiparticle description of the quark-gluon plasma, 22) dissociation of excited quarkonia states, 23) high-mass dimuon and B {yields} J/{psi} production in ultrarelativistic heavy ion collisions, 24) strange hyperon production in p + p and p + Pb interactions from NA49, 25) heavy quarkonium hadron cross-section, 26) a new method of flow analysis, 27) low mass dilepton production and chiral symmetry restoration, 28) classical initial conditions for nucleus-nucleus collisions, 29) numerical calculation of quenching weights, 30) strangeness enhancement energy dependence, and 31) heavy quarkonium dissociation.
Tetraquarks Production in Quark-Gluon Plasma with Diquarks
Institute of Scientific and Technical Information of China (English)
MA Zhong-Biao; GAO Chong-Shou
2006-01-01
@@ We present a way to calculate tetraquarks ratios for quark-gluon plasma with diquarks. The ratios of tetraquarks over baryons produced from quark matter are high than hadronic gas model limits. It is a better way to search for four-quark states in relativistic heavy ion collisions. It may become a criterion to judge whether quark-gluon plasma has formed to search for four-quark states in relativistic heavy ion collisions.
Strangeness Production in a Chemically Equilibrating Quark-Gluon Plasma
Institute of Scientific and Technical Information of China (English)
HE Ze-Jun; LONG Jia-Li; MA Yu-Gang; MA Guo-Liang
2004-01-01
@@ We study the strangeness of a chemically equilibrating quark-gluon plasma at finite baryon density based on the and will accelerate with the change of the initial system from a chemically non-equilibrated to an equilibrated system. We also find that the calculated strangeness is very different from the one in the thermodynamic equilibrium system. This study may be helpful to understand the formation of quark-gluon plasma via a chemically non-equilibrated evolution framework.
Collective Flow signals the Quark Gluon Plasma
Bratkovskaya, E. L.; Bleicher, M.; Greiner, C.; Muronga, A.; Paech, K.; Reiter, M.; Scherer, S.; Soff, S.; Xu, Z.; Zeeb, G.; Zschiesche, D.; Tavares, B.; Portugal, L.; Aguiar, C.; Kodama, T.; Grassi, F.; Hama, Y.; Osada, T.; Sokolowski, O.; Werner, K.; Gallmeister, K.; Cassing, W.; Stöcker, H.
2004-12-01
A critical discussion of the present status of the CERN experiments on charm dynamics and hadron collective flow is given. We emphasize the importance of the flow excitation function from 1 to 50 AṡGeV: here the hydrodynamic model has predicted the collapse of the v1-flow and of the v2-flow at ˜ 10 AṡGeV; at 40 AṡGeV it has been recently observed by the NA49 collaboration. Since hadronic rescattering models predict much larger flow than observed at this energy we interpret this observation as potential evidence for a first order phase transition at high baryon density ρB. A detailed discussion of the collective flow as a barometer for the equation of state (EoS) of hot dense matter at RHIC follows. Additionally, detailed transport studies show that the away-side jet suppression can only partially (QGP formed at RHIC — can give further information on the equation of state (EoS) and transport coefficients of the Quark Gluon Plasma (QGP).
Modeling Quark Gluon Plasma Using CHIMERA
Abelev, Betty
2011-09-01
We attempt to model Quark Gluon Plasma (QGP) evolution from the initial Heavy Ion collision to the final hadronic gas state by combining the Glauber model initial state conditions with eccentricity fluctuations, pre-equilibrium flow, UVH2+1 viscous hydrodynamics with lattice QCD Equation of State (EoS), a modified Cooper-Frye freeze-out and the UrQMD hadronic cascade. We then evaluate the model parameters using a comprehensive analytical framework which together with the described model we call CHIMERA. Within our framework, the initial state parameters, such as the initial temperature (Tinit), presence or absence of initial flow, viscosity over entropy density (η/S) and different Equations of State (EoS), are varied and then compared simultaneously to several experimental data observables: HBT radii, particle spectra and particle flow. χ2/nds values from comparison to the experimental data for each set of initial parameters will then used to find the optimal description of the QGP with parameters that are difficult to obtain experimentally, but are crucial to understanding of the matter produced.
Modeling Quark Gluon Plasma Using CHIMERA
Abelev, Betty B I
2011-01-01
We attempt to model Quark Gluon Plasma (QGP) evolution from the initial Heavy Ion collision to the final hadronic gas state by combining the Glauber model initial state conditions with eccentricity fluctuations, pre-equilibrium flow, UVH2+1 viscous hydrodynamics with lattice QCD Equation of State (EoS), a modified Cooper-Frye freeze-out and the UrQMD hadronic cascade. We then evaluate the model parameters using a comprehensive analytical framework which together with the described model we call CHIMERA. Within our framework, the initial state parameters, such as the initial temperature (T$_{\\mathrm{init}}$), presence or absence of initial flow, viscosity over entropy density ($\\eta$/s) and different Equations of State (EoS), are varied and then compared simultaneously to several experimental data observables: HBT radii, particle spectra and particle flow. $\\chi^2$/nds values from comparison to the experimental data for each set of initial parameters will then used to find the optimal description of the QGP wi...
Inflating metastable quark-gluon plasma universe.
Jenkovszky, L.
The cosmic evolution of our universe before and after the assumed confinement phase transition is studied within the homogeneous, isotropic and spatially flat model. The Friedmann equation, describing its evolution is appended by an equation of state (EOS) of the quark-gluon plasma. A specifically interesting feature of this EOS, derived both in the content of the quark model (and quantum chromodynamics) and the S-matrix formulation of statistical mechanics is the presence of a local minimum in the pressure vs. temperature dependence, that may be the origin of the exponential expansion of our universe, called inflation. The conditions necessary for the deep supercooling, accompanied by nucleation in a first-order phase transition, have been investigated. The nucleation rate (and consequently the probability of the deep supercooling indispensable for the inflation) are shown to depend essentially on the surface tension of the created bubbles. The possibility of a "nuclear inflation" - the analogue of the above scenario in heavy ion collisions - is also discussed.
Effective degrees of freedom of the quark-gluon plasma
Energy Technology Data Exchange (ETDEWEB)
Castorina, P. [Dipartimento di Fisica, Universita di Catania, and INFN Sezione di Catania, Via Santa Sofia 64, I-95100 Catania (Italy); Mannarelli, M. [Center for Theoretical Physics, Laboratory for Nuclear Science and Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)]. E-mail: massimo@lns.mit.edu
2007-01-25
The effective degrees of freedom of the quark-gluon plasma are studied in the temperature range {approx}(1-2)T{sub c}. We show that including light bosonic states one can reproduce the pressure and energy density of the quark-gluon plasma obtained by lattice simulations. The number of the bosonic states required is at most of the order of 20, consistent with the number of light mesonic states and in disagreement with a recently proposed picture of the quark-gluon plasma as a system populated with exotic bound states. We also constrain the quark quasiparticle chiral invariant mass to be {approx}300 MeV. Some remarks regarding the role of the gluon condensation and the baryon number-strangeness correlation are also presented.
Holographic Multiquarks in the Quark-Gluon Plasma: A Review
Directory of Open Access Journals (Sweden)
Piyabut Burikham
2011-01-01
Full Text Available We review the holographic multiquark states in the deconfined quark-gluon plasma. Nuclear matter can become deconfined by extremely high temperature and/or density. In the deconfined nuclear medium, bound states with colour degrees of freedom are allowed to exist. Using holographic approach, the binding energy and the screening length of the multiquarks can be calculated. Using the deconfined Sakai-Sugimoto model, the phase diagram of the multiquark phase, the vacuum phase, and the chiral-symmetric quark-gluon plasma can be obtained. Then we review the magnetic properties of the multiquarks and their phase diagrams. The multiquark phase is compared with the pure pion gradient, the magnetized vacuum, and the chiral-symmetric quark-gluon plasma phases. For moderate temperature and sufficiently large density at a fixed magnetic field, the mixed phase of multiquark and pion gradient is the most energetically preferred phase.
Anomalous Viscosity of the Quark-Gluon Plasma
Hong, Juhee
2013-01-01
The shear viscosity of the quark-gluon plasma is predicted to be lower than the collisional viscosity for weak coupling. The estimated ratio of the shear viscosity to entropy density is rather close to the ratio calculated by N = 4 super Yang-Mills theory for strong coupling, which indicates that the quark-gluon plasma might be strongly coupled. However, in presence of momentum anisotropy, the Weibel instability can arise and affect transport properties. Shear viscosity can be lowered by enhanced collisionality due to turbulence, but the decorrelation time and its relation to underlying dynamics and color-magnetic fields have not been calculated self-consistently. In this paper, we use resonance broadening theory for strong turbulence to calculate the anomalous viscosity of the quark-gluon plasma for nonequilibrium. For saturated Weibel instability, we estimate the scalings of the decorrelation rate and viscosity and compare these with collisional transport. This calculation yields an explicit connection betw...
The refractive index in the viscous quark-gluon plasma
Jiang, Bing-feng; Li, Jia-rong; Gao, Yan-Jun
2013-01-01
Under the framework of the viscous chromohydrodynamics, the gluon self-energy is derived for the quark-gluon plasma with shear viscosity. The viscous electric permittivity and magnetic permeability are evaluated from the gluon self-energy, through which the refraction index %in the %viscous quark-gluon plasma is investigated. The numerical analysis indicates that the refractive index becomes negative in some frequency range. The start point for that frequency range is around the electric permittivity pole, and the magnetic permeability pole determines the end point. As the increase of $\\eta/s$, the frequency range for the negative refraction becomes wider.
Nonperturbative effects in a rapidly expanding quark gluon plasma
Mohanty, A K; Gleiser, Marcello; 10.1103/PhysRevC.65.034908
2002-01-01
Within first-order phase transitions, we investigate pretransitional effects due to the nonperturbative, large-amplitude thermal fluctuations which can promote phase mixing before the critical temperature is reached from above. In contrast with the cosmological quark-hadron transition, we find that the rapid cooling typical of the relativistic heavy ion collider and large hadron collider experiments and the fact that the quark-gluon plasma is chemically unsaturated suppress the role of nonperturbative effects at current collider energies. Significant supercooling is possible in a (nearly) homogeneous state of quark gluon plasma. (24 refs).
The quark gluon plasma: Lattice computations put to experimental test
Indian Academy of Sciences (India)
Sourendu Gupta
2003-11-01
I describe how lattice computations are being used to extract experimentally relevant features of the quark gluon plasma. I deal speciﬁcally with relaxation times, photon emissivity, strangeness yields, event-by-event ﬂuctuations of conserved quantities and hydrodynamic ﬂow. Finally I give evidence that the plasma is rather liquid-like in some ways.
Quark and Gluon Relaxation in Quark-Gluon Plasmas
Heiselberg, H.; Pethick, C. J.
1993-01-01
The quasiparticle decay rates for quarks and gluons in quark-gluon plasmas are calculated by solving the kinetic equation. Introducing an infrared cutoff to allow for nonperturbative effects, we evaluate the quasiparticle lifetime at momenta greater than the inverse Debye screening length to leading order in the coupling constant.
Quark and Gluon Relaxation in Quark-Gluon Plasmas
Heiselberg, H.; Pethick, C. J.
1993-01-01
The quasiparticle decay rates for quarks and gluons in quark-gluon plasmas are calculated by solving the kinetic equation. Introducing an infrared cutoff to allow for nonperturbative effects, we evaluate the quasiparticle lifetime at momenta greater than the inverse Debye screening length to leading order in the coupling constant.
Nonlinear Landau damping in quark-gluon plasma
Xiaofei, Zhang; Jiarong, Li
1995-08-01
The semiclassical kinetic equations for the quark-gluon plasma (QGP) are discussed by the multiple time-scale method. The mechanism of nonlinear Landau damping owing to non-Abelian and nonlinear wave-particle interactions in QGP is investigated, and the nonlinear Landau damping rate for the longitudinal color eigenwaves in the long-wavelength limit is calculated.
Holographic Wilson loops in anisotropic quark-gluon plasma.
Ageev, Dmitry
2016-10-01
The nonequilibrium properties of the anisotropic quark-gluon plasma are condidered from the holographic viewpoint. Lifshitz-like solution is considered as a holographic dual of anisotropic QGP. The black brane formation in such background is considered as a thermalization in dual theory. As a probe of thermalization we consider rectangular spatial Wilson loops with different orientation.
Holographic Wilson loops in anisotropic quark-gluon plasma.
Directory of Open Access Journals (Sweden)
Ageev Dmitry
2016-01-01
Full Text Available The nonequilibrium properties of the anisotropic quark-gluon plasma are condidered from the holographic viewpoint. Lifshitz-like solution is considered as a holographic dual of anisotropic QGP. The black brane formation in such background is considered as a thermalization in dual theory. As a probe of thermalization we consider rectangular spatial Wilson loops with different orientation.
Origin of Temperature of Quark-Gluon Plasma in Heavy Ion Collisions
Xu, Xiao-Ming
2015-01-01
Initially produced quark-gluon matter at RHIC and LHC does not have a temperature. A quark-gluon plasma has a high temperature. From this quark-gluon matter to the quark-gluon plasma is the early thermalization or the rapid creation of temperature. Elastic three-parton scattering plays a key role in the process. The temperature originates from the two-parton scattering, the three-parton scattering, the four-parton scattering and so forth in quark-gluon matter.
Quark-gluon plasma in strong magnetic fields
Energy Technology Data Exchange (ETDEWEB)
Kalaydzhyan, Tigran
2013-04-15
One of the fundamental problems in subatomic physics is the determination of properties of matter at extreme temperatures, densities and electromagnetic fields. The modern ultrarelativistic heavy-ion experiments are able to study such states (the quark-gluon plasma) and indicate that the physics at extreme conditions differs drastically from what is known from the conventional observations. Also the theoretical methods developed mostly within the perturbative framework face various conceptual problems and need to be replaced by a nonperturbative approach. In this thesis we study the physics of the strongly-coupled quark-gluon plasma in external magnetic fields as well as general electromagnetic and topological properties of the QCD and QCD-like systems. We develop and apply various nonperturbative techniques, based on e.g. gauge-gravity correspondence, lattice QCD simulations, relativistic hydrodynamics and condensed-matter-inspired models.
Holographic quark-gluon plasmas at finite quark density
Energy Technology Data Exchange (ETDEWEB)
Bigazzi, F. [Dipartimento di Fisica e Astronomia, Universita di Firenze, Sesto Fiorentino (Firenze), Pisa (Italy); INFN, Sezione di Torino (Italy); Cotrone, A. [Dipartimento di Fisica, Universita di Torino (Italy); Mas, J. [Departamento de Fisica de Particulas, Universidade de Santiago de Compostela (Spain); Instituto Galego de Fisica de Altas Enerxias (IGFAE), Santiago de Compostela (Spain); Tarrio, J. [Institute for Theoretical Physics and Spinoza Institute, Universiteit Utrecht, 3584 CE, Utrecht (Netherlands); Mayerson, D. [Institute for Theoretical Physics, University of Amsterdam (Netherlands)
2012-07-15
Gravity solutions holographically dual to strongly coupled quark-gluon plasmas with non-zero quark density are reviewed. They are motivated by the urgency of finding novel tools to explore the phase diagram of QCD-like theories at finite chemical potential. After presenting the solutions and their regime of validity, some of their physical properties are discussed. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
The extent of strangeness equilibration in quark gluon plasma
Indian Academy of Sciences (India)
Dipali Pal; Abhijit Sen; Munshi Golam Mustafa; Dinesh Kumar Srivastava
2003-05-01
The evolution and production of strangeness from chemically equilibrating and transversely expanding quark gluon plasma which may be formed in the wake of relativistic heavy-ion collisions is studied with initial conditions obtained from the self screened parton cascade (SSPC) model. The extent of partonic equilibration increases almost linearly with the square of the initial energy density, which can then be scaled with the number of participants.
Quark-gluon plasma phase transition using cluster expansion method
Syam Kumar, A. M.; Prasanth, J. P.; Bannur, Vishnu M.
2015-08-01
This study investigates the phase transitions in QCD using Mayer's cluster expansion method. The inter quark potential is modified Cornell potential. The equation of state (EoS) is evaluated for a homogeneous system. The behaviour is studied by varying the temperature as well as the number of Charm Quarks. The results clearly show signs of phase transition from Hadrons to Quark-Gluon Plasma (QGP).
RHIC AND THE PURSUIT OF THE QUARK-GLUON PLASMA.
Energy Technology Data Exchange (ETDEWEB)
MITCHELL,J.T.
2001-07-25
There is a fugitive on the loose. Its name is Quark-Gluon Plasma, alias the QGP. The QGP is a known informant with knowledge about the fundamental building blocks of nature that we wish to extract. This briefing will outline the status of the pursuit of the elusive QGP. We will cover what makes the QGP tick, its modus operandi, details on how we plan to hunt the fugitive down, and our level of success thus far.
Intermediate mass dilepton production during the chemical equilibration of quark gluon plasma
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
The production of dileptons from the chemically equilibrating quark gluon plasma in the intermediate mass region has been studied. Comparing with the calculated results based on the thermodynamic equilibrium system of quark gluon plasma, it has been found that the quark phase of the chemically equilibrating system gives rise to an even larger enhancement of the dileptons production. Therefore, such an enhancement of dilepton production may signal the formation of quark gluon plasma.
Turbulent thermalization of the Quark Gluon Plasma
Berges, J; Schlichting, S; Venugopalan, R
2013-01-01
Classical-statistical lattice gauge theory simulations are employed to demonstrate the existence of a nonthermal fixed point in the space-time evolution of heavy ion collisions at ultrarelativistic energies. After an initial transient regime dominated by plasma instabilities and free streaming, the ensuing overpopulated non-Abelian plasma exhibits the universal self-similar dynamics characteristic of wave turbulence observed in a large variety of physical systems across different energy scales.
Supercooling of rapidly expanding quark-gluon plasma
Zabrodin, E E; Csernai, László P; Stöcker, H; Greiner, W
1998-01-01
We reexamine the scenario of homogeneous nucleation of the quark-gluon plasma produced in ultra-relativistic heavy ion collisions. A generalization of the standard nucleation theory to rapidly expanding system is proposed. The nucleation rate is derived via the new scaling parameter $\\lambda_Z$. It is shown that the size distribution of hadronic clusters plays an important role in the dynamics of the phase transition. The longitudinally expanding system is supercooled to about 3-6%, then it is reheated, and the hadronization is completed within 6-10 fm/c, i.e. 5-10 times faster than it was estimated earlier, in a strongly nonequilibrium way.
Quark-gluon plasma and topological quantum field theory
Luo, M. J.
2017-03-01
Based on an analogy with topologically ordered new state of matter in condensed matter systems, we propose a low energy effective field theory for a parity conserving liquid-like quark-gluon plasma (QGP) around critical temperature in quantum chromodynamics (QCD) system. It shows that below a QCD gap which is expected several times of the critical temperature, the QGP behaves like topological fluid. Many exotic phenomena of QGP near the critical temperature discovered at Relativistic Heavy Ion Collision (RHIC) are more readily understood by the suggestion that QGP is a topologically ordered state.
Baryon inhomogeneities in a charged quark gluon plasma
Energy Technology Data Exchange (ETDEWEB)
Ray, Avijeet [Indian Institute of Technology Roorkee, Uttarakhand, 247667 (India); Sanyal, Soma, E-mail: sossp@uohyd.ernet.in [School of Physics, University of Hyderabad, Gachibowli, Hyderabad, 500046 (India)
2013-10-07
We study the generation of baryon inhomogeneities in regions of the quark gluon plasma which have a charge imbalance. We find that the overdensity in the baryon lumps for positively charged particles is different from the overdensity due to the negatively charged particles. Since quarks are charged particles, the probability of forming neutrons or protons in the lumps would thus be changed. The probability of forming hadrons having quarks of the same charges would be enhanced. This might have interesting consequences for the inhomogeneous nucleosynthesis calculations.
Linear Landau damping in strongly relativistic quark gluon plasma
Energy Technology Data Exchange (ETDEWEB)
Murtaza, G.; Khattak, N.A.D.; Shah, H.A. [Salam Chair in Physics, G C Univ., Lahore (Pakistan)]|[Dept. of Physics, G C Univ., Lahore (Pakistan)
2004-07-01
On the basis of semi classical kinetic Vlasov equation for Quark-Gluon plasma (QGP) and Yang-Mills equation in covariant gauge, linear Landau damping for electrostatic perturbations like Langmuir waves is investigated. For the extreme relativistic case, wherein the thermal speed of the particles exceeds the phase velocity of the perturbations, the linear Landau damping is absent. However, a departure from extreme relativistic case generates an imaginary component of the frequency giving rise to linear Landau damping effect. The relevant integral for the conductivity tensor has been evaluated and the dispersion relation for the longitudinal part of the oscillation obtained. (orig.)
Surface Emission of Quark Gluon Plasma at RHIC and LHC
Institute of Scientific and Technical Information of China (English)
XIANG Wen-Chang; WAN Ren-Zhuo; ZHOU Dai-Cui
2008-01-01
Within the framework of a factorization model, we study the behaviour of nuclear modification factor in Au-Au collisions at RHIC and Pb-Pb collisions at LHC. We find that the nuclear modification factor is inversely proportional to the radius of the quark-gluon plasma and is dominated by the surface emission of hard jets. We predict the nuclear modification factor RLHCAA～0.15 in central Pb-Pb collisions at LHC. The study shows that the factorization model can be used to describe the centrality dependence of nuclear modification factor of the high transverse momentum particles produced in heavy ion collisions at both RHIC and LHC.
Quark-Gluon Plasma: from accelerator experiments to early Universe
Rosnet, P
2015-01-01
In the Big Bang scenario, the early Universe is characterized by the {\\it particle era}, i.e. a Universe made of particles. This period connects both scales of fundamental physics: infinitesimally small and infinitely large. So, particle physics and in particular experimental programs at accelerators can bring valuable inputs for the understanding of the early Universe and its evolution. These proceedings discuss the impact of the Quantum ChromoDynamics phase transition experienced by the {\\it particle era} in the expanding Universe, which is connected to the study of the Quark-Gluon Plasma produced in heavy-ion physics experiments.
From Color Fields to Quark Gluon Plasma
Fries, R J; Li, Y; Fries, Rainer J.; Kapusta, Joseph I.; Li, Yang
2006-01-01
We discuss a model for the energy distribution and the early space-time evolution of a heavy ion collision. We estimate the gluon field generated in the wake of hard processes and through primordial fluctuations of the color charges in the nuclei. Without specifying the dynamical mechanism of thermalization we calculate the energy momentum tensor of the following plasma phase. The results of this model can be used as initial conditions for a further hydrodynamic evolution.
Evolution to the Quark-Gluon Plasma
Fukushima, Kenji
2016-01-01
Theoretical studies on the early-time dynamics in the ultra-relativistic heavy-ion collisions are reviewed including pedagogical introductions on the initial condition with small-x gluons treated as a color glass condensate, the bottom-up thermalization scenario, plasma/glasma instabilities, basics of some formulations such as the kinetic equations and the classical statistical simulation. More detailed discussions follow to make an overview of recent developments on the fast isotropization, the onset of hydrodynamics, and the transient behavior of momentum spectral cascades.
Quark Gluon Plasma: Surprises from strongly coupled QCD matter
Jacak, Barbara
2017-01-01
Quantum Chromodynamics has long predicted a transition from normal hadronic matter to a phase where the quarks and gluons are no longer bound together and can move freely. Quark gluon plasma is now produced regularly in collisions of heavy nuclei at very high energy at both the Relativistic Heavy Ion Collider (RHIC) in the U.S. and at the LHC in Europe. Quark gluon plasma exhibits remarkable properties. Its vanishingly small shear viscosity to entropy density ratio means that it flows essentially without internal friction, making it one of the most ``perfect'' liquids known. It is also very opaque to transiting particles including heavy charm quarks, though the exact mechanism for this is not yet understood. Recent data suggest that even very small colliding systems may produce a droplet of plasma. The similarities to strongly coupled or correlated systems in ultra-cold atoms and condensed matter are striking, and have inspired novel theoretical descriptions growing out of string theory. It remains a mystery how this plasma emerges from cold, dense gluonic matter deep inside nuclei. I will discuss how a future electron-ion collider can help address this question.
Working group report: Heavy-ion physics and quark-gluon plasma
Indian Academy of Sciences (India)
Munshi G Mustafa; Sudhir Raniwala; T Awes; B Rai; R S Bhalerao; J G Contreras; R V Gavai; S K Ghosh; P Jaikumar; G C Mishra; A P Mishra; H Mishra; B Mohanty; J Nayak; J-Y Ollitrault; S C Phatak; L Ramello; R Ray; P K Sahu; A M Srivastava; D K Srivastava; V K Tiwari
2006-11-01
This is the report of Heavy Ion Physics and Quark-Gluon Plasma at WHEPP-09 which was part of Working Group-4. Discussion and work on some aspects of quark-gluon plasma believed to have created in heavy-ion collisions and in early Universe are reported.
Chemical Evolution of Strongly Interacting Quark-Gluon Plasma
Directory of Open Access Journals (Sweden)
Ying-Hua Pan
2014-01-01
Full Text Available At very initial stage of relativistic heavy ion collisions a wave of quark-gluon matter is produced from the break-up of the strong color electric field and then thermalizes at a short time scale (~1 fm/c. However, the quark-gluon plasma (QGP system is far out of chemical equilibrium, especially for the heavy quarks which are supposed to reach chemical equilibrium much late. In this paper a continuing quark production picture for strongly interacting QGP system is derived, using the quark number susceptibilities and the equation of state; both of them are from the results calculated by the Wuppertal-Budapest lattice QCD collaboration. We find that the densities of light quarks increase by 75% from the temperature T=400 MeV to T=150 MeV, while the density of strange quark annihilates by 18% in the temperature region. We also offer a discussion on how this late production of quarks affects the final charge-charge correlations.
Color Instabilities in the Quark-Gluon Plasma
Mrowczynski, Stanislaw; Strickland, Michael
2016-01-01
When the quark-gluon plasma (QGP) - a system of deconfined quarks and gluons - is in a nonequilibrium state, it is usually unstable with respect to color collective modes. The instabilities, which are expected to strongly influence dynamics of the QGP produced in relativistic heavy-ion collisions, are extensively discussed under the assumption that the plasma is weakly coupled. We begin by presenting the theoretical approaches to study the QGP, which include: field theory methods based on the Keldysh-Schwinger formalism, classical and kinetic theories, and fluid techniques. The dispersion equations, which give the spectrum of plasma collective excitations, are analyzed in detail. Particular attention is paid to a momentum distribution of plasma constituents which is obtained by deforming an isotropic momentum distribution. Mechanisms of chromoelectric and chromomagnetic instabilities are explained in terms of elementary physics. The Nyquist analysis, which allows one to determine the number of solutions of a ...
Phenomenological review on Quark-Gluon Plasma: concepts vs observations
Pasechnik, Roman
2016-01-01
In this review, we present an up-to-date phenomenological summary of research developments in physics of the Quark-Gluon Plasma (QGP). A short historical perspective and theoretical motivation for this rapidly developing field of contemporary Particle Physics is provided. In addition, we introduce and discuss the role of the QCD ground state, non-perturbative and lattice QCD results on the QGP properties as well as the transport models used to make a connection between theory and experiment. The experimental part presents the selected results on bulk observables, hard and penetrating probes obtained in the ultra-relativistic heavy-ion experiments carried out at BNL RHIC, CERN SPS and LHC accelerators. We also give a brief overview of new developments related to the ongoing searches of the QCD critical point and to the collectivity in small ($p+p$ and $p+A$) systems.
Quark-gluon plasma connected to finite heat bath
Energy Technology Data Exchange (ETDEWEB)
Biro, Tamas S.; Gabor Barnafoeldi, Gergely; Van, Peter [Wigner Research Centre for Physics of the HAS, P.O.Box 49, Budapest (Hungary)
2013-09-15
We derive entropy formulas for finite reservoir systems, S{sub q}, from universal thermostat independence and obtain the functional form of the corresponding generalized entropy-probability relation. Our result interprets thermodynamically the subsystem temperature, T{sub 1}, and the index q in terms of the temperature, T, entropy, S, and heat capacity, C of the reservoir as T{sub 1}=T exp (-S/C) and q=1-1/C. In the infinite C limit, irrespective of the value of S, the Boltzmann-Gibbs approach is fully recovered. We apply this framework for the experimental determination of the original temperature of a finite thermostat, T, from the analysis of hadron spectra produced in high-energy collisions, by analyzing frequently considered simple models of the quark-gluon plasma. (orig.)
Chiral superfluidity of the quark-gluon plasma
Kalaydzhyan, Tigran
2013-01-01
In this paper we argue that the strongly coupled quark-gluon plasma can be considered as a chiral superfluid. The "normal" component of the fluid is the thermalized matter in common sense, while the "superfluid" part consists of long wavelength (chiral) fermionic states moving independently. We use several nonperturbative techniques to demonstrate that. First, we analyze the fermionic spectrum in the deconfinement phase (Tc < T < 2 Tc) using lattice (overlap) fermions and observe a gap between near-zero modes and the bulk of the spectrum. Second, we use the bosonization procedure with a finite cut-off and obtain a dynamical axion-like field out of the chiral fermionic modes. Third, we use relativistic hydrodynamics for macroscopic description of the effective theory obtained after the bosonization. Finally, solving the hydrodynamic equations in gradient expansion, we find that in the presence of external electromagnetic fields the motion of the "superfluid" component gives rise to the chiral magnetic, c...
Quantum Gravity effect on the Quark-Gluon Plasma
Elmashad, I; Abou-Salem, L I; Nabi, Jameel-Un; Tawfik, A
2012-01-01
The Generalized Uncertainty Principle (GUP), which has been predicted by various theories of quantum gravity near the Planck scale is implemented on deriving the thermodynamics of ideal Quark-Gluon Plasma (QGP) consisting of two massless quark flavors at the hadron-QGP phase equilibrium and at a vanishing chemical potential. The effective degrees of freedom and MIT bag pressure are utilized to distinguish between the hadronic and partonic phases. We find that GUP makes a non-negligible contribution to all thermodynamic quantities, especially at high temperatures. The asymptotic behavior of corresponding QGP thermodynamic quantities characterized by the Stephan-Boltzmann limit would be approached, when the GUP approach is taken into consideration.
Quark-gluon plasma: Status of heavy ion physics
Indian Academy of Sciences (India)
R V Gavai
2000-07-01
Lattice quantum chromodynamics (QCD), deﬁned on a discrete space–time lattice, leads to a spectacular non-perturbative prediction of a new state of matter, called quark-gluon plasma (QGP), at sufﬁciently high temperatures or equivalently large energy densities. The experimental programs of CERN, Geneva and BNL, New York of relativistic heavy ion collisions are expected to produce such energy densities, thereby providing us a chance to test the above prediction. After a brief introduction of the necessary theoretical concepts, I will present a critical review of the experimental results already obtained by the various experiments in order to examine whether QGP has already been observed by them.
Photons from quark gluon plasma and hot hadronic matter
Indian Academy of Sciences (India)
Jan-E Alam
2003-04-01
The productions of real photons from quark gluon plasma and hot hadronic matter formed after the nucleus–nucleus collisions at ultra-relativistic energies are discussed. The effects of the spectral shift of the hadrons at ﬁnite temperature on the production of photons are investigated. On the basis of the present analysis it is shown that the photon spectra measured by WA98 collaboration in Pb + Pb collisions at CERN SPS energies can be explained by both QGP as well as hadronic initial states if the spectral shift of hadrons at ﬁnite temperature is taken into account. Several other works on the analysis of WA98 photon data have also been brieﬂy discussed.
Some applications of thermal field theory to quark-gluon plasma
Indian Academy of Sciences (India)
Munshi G Mustafa
2006-04-01
We briefly introduce the thermal field theory within imaginary time formalism, the hard thermal loop perturbation theory and some of its applications to the physics of the quark-gluon plasma, possibly created in relativistic heavy-ion collisions.
Momentum broadening in unstable quark-gluon plasma
Carrington, M E; Schenke, B
2016-01-01
Quark-gluon plasma produced at the early stage of ultrarelativistic heavy ion collisions is unstable, if weakly coupled, due to the anisotropy of its momentum distribution. Chromomagnetic fields are spontaneously generated and can reach magnitudes much exceeding typical values of the fields in equilibrated plasma. We consider a high energy test parton traversing an unstable plasma that is populated with strong fields. We study the momentum broadening parameter $\\hat q$ which determines the radiative energy loss of the test parton. We develop a formalism which gives $\\hat q$ as the solution of an initial value problem, and we focus on extremely oblate plasmas which are physically relevant for relativistic heavy ion collisions. The parameter $\\hat q$ is found to be strongly dependent on time. For short times it is of the order of the equilibrium value, but at later times $\\hat q$ grows exponentially due to the interaction of the test parton with unstable modes and becomes much bigger than the value in equilibri...
Phenomenological aspects of an anisotropic quark-gluon plasma
Energy Technology Data Exchange (ETDEWEB)
Martinez Guerrero, Mauricio
2010-04-30
In this work we investigate phenomenological aspects of an anisotropic quark-gluon plasma. In the first part of this thesis, we formulate phenomenologicalmodels that take into account the momentumspace anisotropy of the system developed during the expansion of the fireball at early-times. By including the proper-time dependence of the parton hard momentum scale, p{sub hard}({tau}), and the plasma anisotropy parameter, {xi}({tau}), the proposed models allow us to interpolate from 0+1 pre-equilibrated expansion at early-times to 0+1 ideal hydrodynamics at late times. We study dilepton production as a valuable observable to experimentally determine the isotropization time of the system as well as the degree of anisotropy developed at early-times. We generalize our interpolating models to include the rapidity dependence of p{sub hard} and consider its impact on forward dileptons. Next, we discuss how to constrain the onset of hydrodynamics by demanding two requirements of the solutions to the equations of motion of viscous hydrodynamics. We show this explicitly for 0+1 dimensional 2nd-order conformal viscous hydrodynamics and find that the initial conditions are non-trivially constrained. Finally, we demonstrate how to match the initial conditions for 0+1 dimensional viscous hydrodynamics from pre-equilibrated expansion. We analyze the dependence of the entropy production on the pre-equilibrium phase and discuss limitations of the standard definitions of the non-equilibrium entropy in kinetic theory. (orig.)
KdV solitons in a cold quark gluon plasma
Fogaça, D A; Filho, L G Ferreira
2011-01-01
The relativistic heavy ion program developed at RHIC and now at LHC motivated a deeper study of the properties of the quark gluon plasma (QGP) and, in particular, the study of perturbations in this kind of plasma. We are interested on the time evolution of perturbations in the baryon and energy densities. If a localized pulse in baryon density could propagate throughout the QGP for long distances preserving its shape and without loosing localization, this could have interesting consequences for relativistic heavy ion physics and for astrophysics. A mathematical way to proove that this can happen is to derive (under certain conditions) from the hydrodynamical equations of the QGP a Korteveg-de Vries (KdV) equation. The solution of this equation describes the propagation of a KdV soliton. The derivation of the KdV equation depends crucially on the equation of state (EOS) of the QGP. The use of the simple MIT bag model EOS does not lead to KdV solitons. Recently we have developed an EOS for the QGP which include...
Strongly coupled quark-gluon plasma in heavy ion collisions
Shuryak, Edward
2017-07-01
A decade ago, a brief summary of the field of the relativistic heavy ion physics could be formulated as the discovery of strongly coupled quark-gluon plasma, sQGP for short, a near-perfect fluid with surprisingly large entropy-density-to-viscosity ratio. Since 2010, the LHC heavy ion program added excellent new data and discoveries. Significant theoretical efforts have been made to understand these phenomena. Now there is a need to consolidate what we have learned and formulate a list of issues to be studied next. Studies of angular correlations of two and more secondaries reveal higher harmonics of flow, identified as the sound waves induced by the initial state perturbations. As in cosmology, detailed measurements and calculations of these correlations helped to make our knowledge of the explosion much more quantitative. In particular, their damping had quantified the viscosity. Other kinetic coefficients—the heavy-quark diffusion constants and the jet quenching parameters—also show enhancements near the critical point T ≈Tc. Since densities of QGP quarks and gluons strongly decrease at this point, these facts indicate large role of nonperturbative mechanisms, e.g., scattering on monopoles. New studies of the p p and p A collisions at high multiplicities reveal collective explosions similar to those in heavy ion A A collisions. These "smallest drops of the sQGP" revived debates about the initial out-of-equilibrium stage of the collisions and mechanisms of subsequent equilibration.
Electromagnetic Radiation From An Equilibrium Quark -Gluon Plasma System
Singh, S S; Jha, Agam K.
2006-01-01
We study the electromagnetic radiation from a hot and slightly strong interacting fireball system of quark-gluon plasma using the Boltzmann distribution function for the incoming particles and Bose-Einstein distribution for gluon in first calculation of electromagnetic radiation and Fermi-Dirac distribution for quark, antiquark and Boltzmann distribution for gluon in our second calculation. The thermal photon emission rate is found that it is infrared divergent for massless quarks which are discussed by many authors and regulate this divergence using different cut-off in the qurak mass. However we remove this divergence using the same technique of Braaten and Pisarski in the thermal mass of the system by using our model calculation in the coupling parameter. Thus the production rate of the thermal photon is found to be smoothly worked by this cut-off technique of our model. The result is found to be matched with the most of the theoretical calculations and it is in the conformity with the experimental results...
Creating the Primordial Quark-Gluon Plasma at the LHC
Harris, John W.
2013-04-01
Ultra-relativistic collisions of heavy ions at the Large Hadron Collider (LHC) and the Relativistic Heavy Ion Collider (RHIC) create an extremely hot system at temperatures (T) expected only within the first microseconds after the Big Bang. At these temperatures (T ˜ 2 x 10^12 K), a few hundred thousand times hotter than the sun's core, the known ``elementary'' particles cannot exist and matter ``melts'' to form a ``soup'' of quarks and gluons, called the quark-gluon plasma (QGP). This ``soup'' flows easily, with extremely low viscosity, suggesting a nearly perfect hot liquid of quarks and gluons. Furthermore, the liquid is dense, highly interacting and opaque to energetic probes (fast quarks or gluons). RHIC has been in operation for twelve years and has established an impressive set of findings. Recent results from heavy ion collisions at the LHC extend the study of the QGP to higher temperatures and harder probes, such as jets (energetic clusters of particles), particles with extremely large transverse momenta and those containing heavy quarks. I will present a motivation for physics in the field and an overview of the new LHC heavy ion results in relation to results from RHIC.
Quarkonium states in an anisotropic quark-gluon plasma
Energy Technology Data Exchange (ETDEWEB)
Guo Yun
2009-09-10
In this work we study the properties of quarkonium states in a quark-gluon plasma which, due to expansion and non-zero viscosity, exhibits a local anisotropy in momentum space. We determine the hard-loop resummed gluon propagator in an anisotropic QCD plasma in general linear gauges and define a potential between heavy quarks from the Fourier transform of its static limit. This potential which arises due to one-gluon exchange describes the force between a quark and anti-quark at short distances. It is closer to the vacuum potential as compared to the isotropic Debye screened potential which indicates the reduced screening in an anisotropic QCD plasma. In addition, angular dependence appears in the potential; we find that there is stronger attraction on distance scales on the order of the inverse Debye mass for quark pairs aligned along the direction of anisotropy than for transverse alignment. The potential at long distances, however, is non-perturbative and modeled as a QCD string which is screened at the same scale as the Coulomb field. At asymptotic separation the potential energy is non-zero and inversely proportional to the temperature. With a phenomenological potential model which incorporates the different behaviors at short and long distances, we solve the three-dimensional Schroedinger equation. Our numerical results show that quarkonium binding is stronger at non-vanishing viscosity and expansion rate, and that the anisotropy leads to polarization of the P-wave states. Furthermore, we determine viscosity corrections to the imaginary part of the heavy-quark potential in the weak-coupling hard-loop approximation. The imaginary part is found to be smaller (in magnitude) than at vanishing viscosity. This implies a smaller decay width of quarkonium bound states in an anisotropic plasma. (orig.)
Properties of the quark gluon plasma from lattice QCD
Energy Technology Data Exchange (ETDEWEB)
Mages, Simon Wolfgang
2015-03-02
Quantum Chromodynamics (QCD) is the theory of the strong interaction, the theory of the interaction between the constituents of composite elementary particles (hadrons). In the low energy regime of the theory, standard methods of theoretical physics like perturbative approaches break down due to a large value of the coupling constant. However, this is the region of most interest, where the degrees of freedom of QCD, the color charges, form color-neutral composite elementary particles, like protons and neutrons. Also the transition to more energetic states of matter like the quark gluon plasma (QGP), is difficult to investigate with perturbative approaches. A QGP is a state of strongly interacting matter, which existed shortly after the Big Bang and can be created with heavy ion collisions for example at the LHC at CERN. In a QGP the color charges of QCD are deconfined. This thesis explores ways how to use the non-perturbative approach of lattice QCD to determine properties of the QGP. It focuses mostly on observables which are derived from the energy momentum tensor, like two point correlation functions. In principle these contain information on low energy properties of the QGP like the shear and bulk viscosity and other transport coefficients. The thesis describes the lattice QCD simulations which are necessary to measure the correlation functions and proposes new methods to extract these low energy properties. The thesis also tries to make contact to another non-perturbative approach which is Improved Holographic QCD. The aim of this approach is to use the Anti-de Sitter/Conformal Field Theory (AdS/CFT) correspondence to make statements about QCD with calculations of a five dimensional theory of gravity. This thesis contributes to that work by constraining the parameters of the model action by comparing the predictions with those of measurements with lattice QCD.
Collective flow signals the quark-gluon plasma
Stöcker, H.
2005-03-01
A critical discussion of the present status of the CERN experiments on charm dynamics and hadron collective flow is given. We emphasize the importance of the flow excitation function from 1 to 50 A GeV: here the hydrodynamic model has predicted the collapse of the v-flow and of the v-flow at ˜10 A GeV; at 40 A GeV it has been recently observed by the NA49 Collaboration. Since hadronic rescattering models predict much larger flow than observed at this energy we interpret this observation as evidence for a first order phase transition at high baryon density ρ. A detailed discussion of the collective flow as a barometer for the equation of state (EoS) of hot dense matter at RHIC follows. Here, hadronic rescattering models can explain 2 GeV/c. This is interpreted as evidence for the production of superdense matter at RHIC with initial pressure far above hadronic pressure, p>1 GeV/fm. We suggest that the fluctuations in the flow, v and v, should be measured in future since ideal hydrodynamics predicts that they are larger than 50% due to initial state fluctuations. Furthermore, the QGP coefficient of viscosity may be determined experimentally from the fluctuations observed. The connection of v to jet suppression is examined. It is proven experimentally that the collective flow is not faked by minijet fragmentation. Additionally, detailed transport studies show that the away-side jet suppression can only partially (QGP formed at RHIC—can give further information on the equation of state (EoS) and transport coefficients of the quark-gluon plasma (QGP).
Search and study of Quark Gluon Plasma at the CERN-LHC
Nayak, Tapan
2009-01-01
The major aim of nucleus-nucleus collisions at the LHC is to study the physics of strongly interacting matter and the quark gluon plasma (QGP), formed in extreme conditions of temperature and energy density. We give a brief overview of the experimental program and discuss the signatures and observables for a detailed study of QGP matter.
Introduction to the Quark-Gluon Plasma session in RJC 2014
Maire, Antonin
2015-01-01
This contribution is a brief introduction to the physics of Quark-Gluon Plasma (QGP); the intention is to set the stage for the corresponding session proceedings of the "Rencontre Jeunes Chercheurs 2014". The text consists in a description of the Bjorken scenario of a heavy-ion collision followed by the introduction of the notion of hard probe for QGP studies.
Energy Technology Data Exchange (ETDEWEB)
Redlich, K.
1985-04-01
Strangeness production in hot nuclear matter in the non-interacting gas approximation with an Usub(B)(1)xUsub(S)(1) internal symmetry group is discussed. It is argued that the stangeness abundancy ratio in the quark-gluon plasma as compared to the hadron gas strongly depends on under which thermodynamical circumstances it has been computed.
QCD equations of state and the quark-gluon plasma liquid model
Letessier, Jean; Rafelski, Johann
2003-03-01
Recent advances in the study of equations of state of thermal lattice quantum chromodynamics obtained at nonzero baryon density allow validation of the quark-gluon plasma (QGP) liquid model equations of state (EOS). We study here the properties of the QGP-EOS near to the phase transformation boundary at finite baryon density and show a close agreement with the lattice results.
Equation of state of a quark-gluon plasma using the Cornell potential
Udayanandan, K. M.; Sethumadhavan, P.; Bannur, V. M.
2007-10-01
The equation of state (EOS) of quark-gluon plasma (QGP) using the Cornell potential based on Mayer's cluster expansion is presented. The string constant and the strong coupling constant for QGP are calculated. The EOS developed could describe the lattice EOS for pure gauge, two-flavor and three-flavor QGP qualitatively.
Photons from a Chemically Equilibrating Quark-Gluon Plasma at Finite Baryon Density
Institute of Scientific and Technical Information of China (English)
HE Ze-Jun; LONG Jia-Li; MA Yu-Gang; MA Guo-Liang
2005-01-01
@@ We study hard photon production in a chemically equilibrating quark-gluon plasma at finite baryon density based on the Jüttner distribution of partons of the system. We find that the photon yield is a strongly increasing function of the initial quark chemical potential.
Non-perturbative effects for the Quark-Gluon Plasma equation of state
Energy Technology Data Exchange (ETDEWEB)
Begun, V. V., E-mail: viktor.begun@gmail.com; Gorenstein, M. I., E-mail: goren@bitp.kiev.ua; Mogilevsky, O. A. [Bogolyubov Institute for Theoretical Physics (Ukraine)
2012-07-15
The non-perturbative effects for the Quark-Gluon Plasma (QGP) equation of state (EoS) are considered. The modifications of the bag model EoS are constructed to satisfy the main qualitative features observed for the QGP EoS in the lattice QCD calculations. A quantitative comparison with the lattice results is done for the SU(3) gluon plasma and for the QGP with dynamical quarks. Our analysis advocates a negative value of the bag constant B.
Non-perturbative effects for the Quark-Gluon Plasma equation of state
Begun, V. V.; Gorenstein, M. I.; Mogilevsky, O. A.
2012-07-01
The non-perturbative effects for the Quark-Gluon Plasma (QGP) equation of state (EoS) are considered. The modifications of the bag model EoS are constructed to satisfy the main qualitative features observed for the QGP EoS in the lattice QCD calculations. A quantitative comparison with the lattice results is done for the SU(3) gluon plasma and for the QGP with dynamical quarks. Our analysis advocates a negative value of the bag constant B.
Quark self-energy in an ellipsoidally anisotropic quark-gluon plasma
Kasmaei, Babak S; Strickland, Michael
2016-01-01
We calculate the quark self-energy in a quark-gluon plasma that possesses an ellipsoidal momentum-space anisotropy in the local rest frame. By introducing additional transverse momentum anisotropy parameters into the parton distribution functions, we generalize previous results which were obtained for the case of a spheroidal anisotropy. Our results demonstrate that the presence of anisotropies in the transverse directions affects the real and imaginary parts of quark self-energy and, consequently, the self-energy depends on both the polar and azimuthal angles in the local rest frame of the matter. Our results for the quark self-energy set the stage for the calculation of the effects of ellipsoidal momentum-space anisotropy on quark-gluon plasma photon spectra and collective flow.
Velocity statistics in holographic fluids: magnetized quark-gluon plasma and superfluid flow
Energy Technology Data Exchange (ETDEWEB)
Areán, Daniel [Max-Planck-Institut für Physik (Werner-Heisenberg-Institut),Föhringer Ring 6, D-80805, Munich (Germany); Zayas, Leopoldo A. Pando [The Abdus Salam International Centre for Theoretical Physics,Strada Costiera 11, 34014 Trieste (Italy); Michigan Center for Theoretical Physics, Department of Physics, University of Michigan,450 Church Street, Ann Arbor, MI 48109 (United States); Patiño, Leonardo; Villasante, Mario [Departamento de Física, Facultad de Ciencias, Universidad Nacional Autónoma de México,A.P. 70-542, México D.F. 04510 (Mexico)
2016-10-28
We study the velocity statistics distribution of an external heavy particle in holographic fluids. We argue that when the dual supergravity background has a finite temperature horizon the velocity statistics goes generically as 1/v, compatible with the jet-quenching intuition from the quark-gluon plasma. A careful analysis of the behavior of the classical string whose apparent world sheet horizon deviates from the background horizon reveals that other regimes are possible. We numerically discuss two cases: the magnetized quark-gluon plasma and a model of superfluid flow. We explore a range of parameters in these top-down supergravity solutions including, respectively, the magnetic field and the superfluid velocity. We determine that the velocity statistics goes largely as 1/v, however, as we leave the non-relativistic regime we observe some deviations.
Meiling, Yu; Lianshou, Liu
2008-01-01
Pair distribution function for delocalized quarks in the strongly coupled quark gluon plasma (sQGP) as well as in the states at intermediate stages of crossover from hadronic matter to sQGP are calculated using a molecule-like aggregation model. The shapes of the obtained pair distribution functions exhibit the character of liquid. The increasing correlation length in the process of crossover indicates a diminishing viscosity of the fluid system.
Finite Temperature Lattice QCD - Baryons in the Quark-Gluon Plasma
Aarts, Gert; De Boni, Davide; Hands, Simon; Jäger, Benjamin; Praki, Chrisanthi; Skullerud, Jon-Ivar
2016-01-01
Baryonic correlation functions provide an ideal tool to study parity doubling and chiral symmetry using lattice simulations. We present a study using $2+1$ flavors of anisotropic Wilson clover fermions on the FASTSUM ensembles and find clear evidence that parity doubling emerges in the quark-gluon plasma. This result is confirmed on the level of spectral functions, which are obtained using a MEM reconstruction. We further highlight the importance of Gaussian smearing in this study.
Describing the strongly interacting quark-gluon plasma through the Friedberg-Lee model
Shu, Song; Li, Jia-Rong
2010-10-01
The Friedberg-Lee (FL) model is studied at finite temperature and density. The soliton solutions of the FL model in the deconfinement phase transition are solved and thoroughly discussed for certain boundary conditions. We indicate that the solitons before and after the deconfinement have different physical meanings: the soliton before deconfinement represents hadrons, while the soliton after the deconfinement represents the bound state of quarks which leads to a strongly interacting quark-gluon plasma phase. The corresponding phase diagram is given.
Equation of State of the Quark Gluon Plasma within the Quasi-particle Approach
Begun, Viktor V; Mogilevsky, Oleg A
2010-01-01
We propose simple analytical form of the quark-gluon plasma (QGP) equation of state (EoS) based on a quasi-particle approach. This new EoS satisfies all qualitative features observed in the lattice QCD calculations and gives a good quantitative description of the lattice results in SU(3) gluodynamics. The suggested EoS opens up new possibilities for hydrodynamic and kinetic phenomenological applications in the studies of the QGP.
Quark-gluon plasma freeze-out from a supercooled state?
Csörgö, T
1994-01-01
The quark-gluon plasma, formed in the first 3 fm/c of the heavy ion collisions at RHIC and LHC, supercooles due to nucleation and develops soon a negative pressure in the bag model. The negative pressure yields mechanical instability which may lead to a sudden timelike deflagration to a (super)heated hadron gas. The resulting freeze-out times are shorter than those of the standard nucleation scenario.
A mean field theory for the cold quark gluon plasma applied to stellar structure
Energy Technology Data Exchange (ETDEWEB)
Fogaca, D. A.; Navarra, F. S.; Franzon, B. [Instituto de Fisica, Universidade de Sao Paulo Rua do Matao, Travessa R, 187, 05508-090 Sao Paulo, SP (Brazil); Horvath, J. E. [Instituto de Astronomia, Geofisica e Ciencias Atmosfericas, Universidade de Sao Paulo, Rua do Matao, 1226, 05508-090, Sao Paulo, SP (Brazil)
2013-03-25
An equation of state based on a mean-field approximation of QCD is used to describe the cold quark gluon plasma and also to study the structure of compact stars. We obtain stellar masses compatible with the pulsar PSR J1614-2230 that was determined to have a mass of (1.97 {+-} 0.04 M{sub Circled-Dot-Operator }), and the corresponding radius around 10-11 km.
Astrophysical aspects of neutrino dynamics in ultra-degenerate quark gluon plasma
Adhya, Souvik Priyam
2016-01-01
The cardinal focus of the present review is to explore the role of neutrinos originating from the ultra-dense core of neutron stars composed of quark gluon plasma in the astrophysical scenario. The collective excitations of the quarks involving the neutrinos through the different kinematical processes have been studied. The cooling of the neutron stars as well as pulsar kicks due to asymmetric neutrino emission have been discussed in detail. Results involving calculation of relevant physical quantities like neutrino mean free path and emissivity have been presented in the framework of non-Fermi liquid behavior as applicable to ultra-degenerate plasma.
Yoctosecond metrology through Hanbury Brown-Twiss correlations from a quark-gluon plasma.
Ipp, Andreas; Somkuti, Peter
2012-11-09
Expansion dynamics at the yoctosecond time scale affect the evolution of the quark gluon plasma (QGP) created in heavy ion collisions. We show how these dynamics are accessible through Hanbury Brown-Twiss (HBT) intensity interferometry of direct photons emitted from the interior of the QGP. A detector placed close to the beam axis is particularly sensitive to early polar momentum anisotropies of the QGP. Observing a modification of the HBT signal at the proposed FoCal detector of the LHC ALICE experiment would allow us to measure the isotropization time of the plasma and could provide first experimental evidence for photon double pulses at the yoctosecond time scale.
The thermalization of soft modes in non-expanding isotropic quark gluon plasmas
Blaizot, Jean-Paul; Mehtar-Tani, Yacine
2016-01-01
We discuss the role of elastic and inelastic collisions and their interplay in the thermalization of the quark-gluon plasma. We consider a simplified situation of a static plasma, spatially uniform and isotropic in momentum space. We focus on the small momentum region, which equilibrates first, and on a short time scale. We obtain a simple kinetic equation that allows for an analytic description of the most important regimes. The present analysis suggests that the formation of a Bose condensate, expected when only elastic collisions are present, is strongly hindered by the inelastic, radiative, processes.
Photon production from quark gluon plasma at ﬁnite baryon density
Indian Academy of Sciences (India)
D Dutta; S V S Sastry; A K Mohanty; K Kumar; R K Choudhury
2003-05-01
The photon yield from a baryon-rich quark gluon plasma (QGP) at SPS energy has been estimated. In the QGP phase, rate of photon production is evaluated up to two-loop level. In the hadron phase, dominant contribution from , , mesons has been considered. The evolution of the plasma has been studied with appropriate equation of state in both QGP and hadron phase for a baryon-rich system. At SPS energy, the total photon yield is found to increase marginally in the presence of baryon density.
Heavy Ions at LHC: A Quest for Quark-Gluon Plasma
Bhalerao, Rajeev S
2008-01-01
Quantum Chromo Dynamics (QCD), the theory of strong interactions, predicts a transition of the usual matter to a new phase of matter, called Quark-Gluon Plasma (QGP), at sufficiently high temperatures. The non-perturbative technique of defining a theory on a space-time lattice has been used to obtain this and other predictions about the nature of QGP. Heavy ion collisions at the Large Hadron Collider in CERN can potentially test these predictions and thereby test our theoretical understanding of confinement. This brief review aims at providing a glimpse of both these aspects of QGP.
Nucleation rate of the quark-gluon plasma droplet at ﬁnite quark chemical potential
Indian Academy of Sciences (India)
D S Gosain; S Somorendro Singh; Agam K Jha
2012-05-01
The nucleation rate of quark-gluon plasma (QGP) droplet is computed at ﬁnite quark chemical potential. In the course of computing the nucleation rate, the ﬁnite size effects of the QGP droplet are taken into account. We consider the phenomenological ﬂow parameter of quarks and gluons, which is dependent on quark chemical potential and we calculate the nucleation rate of the QGP droplet with this parameter. While calculating the nucleation rate, we ﬁnd that for low values of quark phenomenological parameter $ q$, nucleation rate is negligible and when increases, nucleation rate increases signiﬁcantly.
Estimation of electric conductivity of the quark gluon plasma via asymmetric heavy-ion collisions
Hirono, Yuji; Hirano, Tetsufumi
2012-01-01
We show that in asymmetric heavy-ion collisions, especially off-central Cu+Au collisions, a sizable strength of electric field directed from Au nucleus to Cu nucleus is generated in the overlapping region, because of the difference in the number of electric charges between the two nuclei. This electric field would induce an electric current in the matter created after the collision, which result in a dipole deformation of the charge distribution. The directed flow parameters $v_1^{\\pm}$ of charged particles turn out to be sensitive to the charge dipole and provide us with information about electric conductivity of the quark gluon plasma.
Shear viscosity $\\eta$ to electric conductivity $\\sigma_{el}$ ratio for the Quark-Gluon Plasma
Puglisi, A.; Plumari, S.; Greco, V.
2014-01-01
The transport coefficients of strongly interacting matter are currently subject of intense theoretical and phenomenological studies due to their relevance for the characterization of the quark-gluon plasma produced in ultra relativistic heavy-ion collisions (uRHIC). We discuss the connection between the shear viscosity to entropy density ratio, $\\eta/s$, and the electric conductivity, $\\sigma_{el}$. Once the relaxation time is tuned to have a minimum value of $\\eta/s=1/4\\pi$ near the critical...
Dilepton production rate in a hot and magnetized quark-gluon plasma
Sadooghi, N
2016-01-01
The differential multiplicity of dileptons in a hot and magnetized quark-gluon plasma, $\\Delta_{B}\\equiv dN_{B}/d^{4}xd^{4}q$, is derived from first principles. The constant magnetic field $B$ is assumed to be aligned in a fixed spatial direction. It is shown that the anisotropy induced by the $B$ field is mainly reflected in the general structure of photon spectral density function. This is related to the imaginary part of the vacuum polarization tensor, $\\mbox{Im}[\\Pi^{\\mu\
Scattering of Quark-Quasiparticles in the Quark-Gluon Plasma
Energy Technology Data Exchange (ETDEWEB)
Mannarelli, M. [Center for Theoretical Physics, Laboratory for Nuclear Science and Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Rapp, R. [Cyclotron Institute and Physics Department, Texas A and M University, College Station, Texas 77843-3366 (United States)
2006-08-07
Employing a Brueckner-type many-body approach, based on a driving potential extracted from lattice QCD, we study light quark properties in a Quark-Gluon Plasma (QGP) at moderate temperatures, T{approx}1-2T{sub c}. The quark-antiquark T-matrix is calculated self-consistently with pertinent quark self-energies. While the repulsive octet channel induces quasiparticle masses of up to 150 MeV, the attractive color-singlet part exhibits resonance structures which lead to quasiparticle widths of {approx}200MeV.
Flow at the SPS and RHIC as a Quark Gluon Plasma Signature
Teaney, D.; LAURET, J.; Shuryak, E. V.
2000-01-01
Radial and elliptic flow in non-central heavy ion collisions can constrain the effective Equation of State(EoS) of the excited nuclear matter. To this end, a model combining relativistic hydrodynamics and a hadronic transport code(RQMD [17]) is developed. For an EoS with a first order phase transition, the model reproduces both the radial and elliptic flow data at the SPS. With the EoS fixed from SPS data, we quantify predictions at RHIC where the Quark Gluon Plasma(QGP) pressure is expected ...
What RHIC experiments and theory tell us about properties of quark-gluon plasma?
Shuryak, Edward
2005-03-01
This brief review summarizes the main experimental discoveries made at RHIC and then discusses their implications. The robust collective flow phenomena are well described by ideal hydrodynamics, with the equation of state (EoS) predicted by lattice simulations. However the transport properties turned out to be unexpected, with rescattering cross section one-to-two orders of magnitude larger than expected from perturbative QCD. These and other theoretical developments indicate that quark-gluon plasma (QGP) produced at RHIC, and probably in a wider temperature region TEoS, viscosity and jet quenching.
Jet flavor tomography of quark gluon plasmas at RHIC and LHC.
Buzzatti, Alessandro; Gyulassy, Miklos
2012-01-13
A new Monte Carlo model of jet quenching in nuclear collisions, CUJET1.0, is applied to predict the jet flavor dependence of the nuclear modification factor for fragments f=π,D,B,e(-) from quenched jet flavors g,u,c,b in central collisions at RHIC and LHC. The nuclear modification factors for different flavors are predicted to exhibit a novel level crossing pattern over a transverse momentum range 5
quark gluon plasmas.
Chemical Equilibration and Dilepton Production of Quark-Gluon Plasma at RHIC Energies
Institute of Scientific and Technical Information of China (English)
龙家丽; 贺泽君; 马国亮; 马余刚; 刘波
2004-01-01
An evolution model of the chemically equilibrating quark-gluon plasma system has been established based on the Jiittner distribution function of partons. By studying the dilepton production of the system, we find that due to high initial temperature, large gluon density of the system as well as large gluon fusion gg → c(c-) cross section in the intermediate mass region, a dominant contribution to dileptons with intermediate masses is provided by quark-antiquark annihilation qq → l(l-) and, especially, thermal charmed quarks from the gluon fusion gg → c(c-) and quark-antiquark annihilation qq → c(c-).
Heavy-Quark Diffusion Dynamics in Quark-Gluon Plasma under Strong Magnetic Fields
Hattori, Koichi; Yee, Ho-Ung; Yin, Yi
2016-01-01
We discuss heavy-quark dynamics in the quark-gluon plasma under a strong magnetic field induced by colliding nuclei. By the use of the diagrammatic resummation techniques for Hard Thermal Loop and the external magnetic field, we show analytic results of heavy-quark diffusion coefficient and drag force which become anisotropic due to the preferred spatial orientation in the magnetic field. We argue that the anisotropic diffusion coefficient gives rise to an enhancement/suppression of the heavy-quark elliptic flow depending on the transverse momentum.
Dynamics of quark-gluon plasma produced in heavy ion collisions
Directory of Open Access Journals (Sweden)
Ruggieri M.
2014-01-01
Full Text Available In this talk, we report on our results about the computation of isotropization and thermalization times of the quark-gluon plasma produced in relativistic heavy ion collisions, as well as of the elliptic flow. Simulation of the evolving fireball is achieved by solving the relativistic Boltzmann equation for the parton distribution function tuned at a fixed shear viscosity to entropy density ratio η/s. Our results show that the saturation in the initial spectrum reduces the efficiency in building-up the elliptic flow. Moreover both thermalization and isotropization times are quite small, approximately of 1 fm/c, if the system is in a strong coupling regime.
Quark Gluon Plasma an Color Glass Condensate at RHIC? The perspective from the BRAHMS experiment
Arsene, I; Beavis, D; Besliu, C; Budick, B; Bøggild, H; Chasman, C; Christensen, C H; Christiansen, P; Cibor, J; Debbe, R; Enger, E; Gaardhøje, J J; Germinario, M; Hansen, O; Holm, A; Holme, A K; Hagel, K; Ito, H; Jakobsen, E; Jipa, A; Jundt, F; Jordre, J I; Jorgensen, C E; Karabowicz, R; Kim, E J; Kozik, T; Larsen, T M; Lee, J H; Lee, Y K; Lindahl, S; Løvhøiden, G; Majka, Z; Makeev, A; Mikelsen, M; Murray, M J; Natowitz, J B; Neumann, B; Nielsen, B S; Ouerdane, D; Planeta, R; Rami, F; Ristea, C; Ristea, O; Röhrich, D; Samset, B H; Sandberg, D; Sanders, S J; Scheetz, R A; Staszel, P; Tveter, T S; Videbaek, F; Wada, R; Yin, Z; Zgura, I S
2004-01-01
We review the main results obtained by the BRAHMS collaboration on the properties of hot and dense hadronic and partonic matter produced in ultrarelativistic heavy ion collisions at RHIC. A particular focus of this paper is to discuss to what extent the results collected so far by BRAHMS, and by the other three experiments at RHIC, can be taken as evidence for the formation of a state of deconfined partonic matter, the so called quark-gluon-plasma (QGP). We also discuss evidence for a possible precursor state to the QGP, i.e. the proposed Color Glass Condensate.
Flavour equilibration studies of quark-gluon plasma with non-zero baryon density
Indian Academy of Sciences (India)
Abhijit Sen
2009-12-01
Flavour equilibration for a thermally equilibrated but chemically non-equilibrated quark-gluon plasma is presented. Flavour equilibration is studied enforcing baryon number conservation. In addition to the usual processes like single additional gluon production $gg \\rightleftharpoons ggg$ and its reverse and quark–antiquark pair production by gluon pair fusion $gg \\rightleftharpoons q_{i}q_{i}^{-}$ and reverse thereof, processes like quark-flavour interchanging $q_{i}q_{i}^{-} \\rightleftharpoons q_{j}q_{j}^{-}$ is also considered. The degree of equilibration is studied comparatively for various reactions/constraints that are being considered.
Gravitational collisions and the quark-gluon plasma
van der Schee, Wilke
2014-01-01
This thesis addresses the thermalisation of heavy-ion collisions within the context of the AdS/CFT duality. The first part clarifies the numerical set-up and studies the relaxation of far-from-equilibrium modes in homogeneous systems. Less trivially we then study colliding shock waves and uncover a transparent regime where the strongly coupled shocks initially pass right through each other. Furthermore, in this regime the later plasma relaxation is insensitive to the longitudinal profile of the shock, implying in particular a universal rapidity shape at strong coupling and high collision energies. Lastly, we study radial expansion in a boost-invariant set-up, allowing us to find good agreement with head-on collisions performed at the LHC accelerator. As a secondary goal of this thesis, a special effort is made to clearly expose numerical computations by providing commented Mathematica notebooks for most calculations presented. Furthermore, we provide interpolating functions of the geometries computed, which c...
Exciting gauge unstable modes of the quark-gluon plasma by relativistic jets
Energy Technology Data Exchange (ETDEWEB)
Mannarelli, M; Manuel, C [Instituto de Ciencias del Espacio (IEEC/CSIC), Campus Universitat Autonoma de Barcelona, Facultat de Ciencies, Torre C5 E-08193 Bellaterra (Barcelona) (Spain)], E-mail: massimo@ieec.uab.es
2008-05-15
We present a study of the properties of the collective modes of a system composed by a thermalized quark-gluon plasma traversed by a relativistic jet of partons. We find that when the jet traverses the system unstable gauge field modes are excited and grow on very short time scales. The aim is to provide a novel mechanism for the description of the jet quenching phenomenon, where the jet crossing the plasma loses energy exciting colored unstable modes. In order to simplify the analysis we employ a linear response approximation, valid for short time scales. We assume that the partons in the jet can be described with a tsunami-like distribution function, whereas we treat the quark-gluon plasma employing two different approaches. In the first approach we adopt a Vlasov approximation for the kinetic equations, in the second approach we solve a set of fluid equations. In both cases we derive the expressions of the dispersion law of the collective unstable modes and compare the results obtained.
Bag model of hadrons, dual QCD thermodynamics and Quark-Gluon Plasma
Chandola, H C; Dehnen, H
2015-01-01
Using the grand canonical ensemble formulation of a multi-particle statistical system, the thermodynamical description of the dual QCD has been presented in terms of the bag model of hadrons and analyzed for the quark-gluon plasma phase of hadronic matter. The dual QCD bag construction has been shown to lead to the radial pressure on the bag surface in terms of the vector glueball masses of the magnetically condensed QCD vacuum. Constructing the grand canonical partition function to deal with the quark-gluon plasma phase of the non-strange hadrons, the energy density and the plasma pressure have been derived and used to understand the dynamics of the associated phase transition. The critical temperature for QGP-hadron phase transition has been derived and numerically estimated by using various thermodynamic considerations. A comparison of the values of the critical temperatures for QGP-hadron phase transition with those obtained for the deconfinement-phase transition, has been shown to lead to the relaxation ...
Primordial Magnetic Field Via Weibel Instability In The Quark Gluon Plasma Phase
Atreya, Abhishek
2016-01-01
The origin of the observed large scale magnetic fields in the Universe is a mystery. The seed of these magnetic fields has been attributed to physical process in the early universe. In this work we provide a mechanism for the generation of a primordial magnetic field in the early universe via the Weibel instability in the quark gluon plasma. The Weibel instability occurs in the plasma if there is an anisotropy in the particle distribution function of the particles. In early universe, the velocity anisotropy required for Weibel instability to operate is generated in the quark gluon plasma by the collapse of closed $Z(3)$ domain walls that arise in the deconfined phase of the QCD (above $T\\sim 200$ MeV). Such large domains can arise in the context of certain low energy scale inflationary models. The closed domains undergo supersonic collapse and the velocity anisotropy is generated in the shocks produced in the wake of the collapsing domain walls. This results in a two stream Weibel instability in the ultra-rel...
Effect of magnetic field on the photon radiation from quark-gluon plasma in heavy ion collisions
Zakharov, B G
2016-01-01
We develop a formalism for the photon emission from the quark-gluon plasma with an external electromagnetic field. We then use it to investigate the effect of magnetic field on the photon emission from the quark-gluon plasma created in $AA$ collisions. We find that even for very optimistic assumption on the magnitude of the magnetic field generated in $AA$ collisions its effect on the photon emission rate is practically negligible. For this reason the magnetic field cannot generate a significant azimuthal asymmetry in the photon spectrum.
Effect of the magnetic field on the photon radiation from quark-gluon plasma in heavy ion collisions
Energy Technology Data Exchange (ETDEWEB)
Zakharov, B.G. [L.D. Landau Institute for Theoretical Physics, Moscow (Russian Federation)
2016-11-15
We develop a formalism for the photon emission from the quark-gluon plasma with an external electromagnetic field. We then use it to investigate the effect of the magnetic field on the photon emission from the quark-gluon plasma created in AA collisions. We find that even for a very optimistic assumption on the magnitude of the magnetic field generated in AA collisions its effect on the photon emission rate is practically negligible. For this reason the magnetic field cannot generate a significant azimuthal asymmetry in the photon spectrum. (orig.)
Magnetic Phase Diagram of Dense Holographic Multiquarks in the Quark-gluon Plasma
Burikham, Piyabut
2011-01-01
We study phase diagram of the dense holographic gauge matter in the Sakai-Sugimoto model in the presence of the magnetic field above the deconfinement temperature. Even above the deconfinement, quarks could form colour bound states through the remaining strong interaction if the density is large. We demonstrate that in the presence of the magnetic field for a sufficiently large baryon density, the multiquark-pion gradient (MQ-$\\mathcal{5}\\phi$) phase is more thermodynamically preferred than the chiral-symmetric quark-gluon plasma. The phase diagrams between the holographic multiquark and the chiral-symmetric quark-gluon plasma phase are obtained at finite temperature and magnetic field. In the mixed MQ-$\\mathcal{5}\\phi$ phase, the pion gradient induced by the external magnetic field is found to be a linear response for small and moderate field strengths. Its population ratio decreases as the density is raised and thus the multiquarks dominate the phase. Temperature dependence of the baryon chemical potential,...
Long wavelength perfect fluidity from short distance jet transport in quark-gluon plasmas
Xu, Jiechen; Gyulassy, Miklos
2015-01-01
We build a new phenomenological framework that bridges the long wavelength bulk viscous transport properties of the strongly-coupled quark-gluon plasma (sQGP) and short distance hard jet transport properties in the QGP. The full nonperturbative chromo-electric (E) and chromo-magnetic (M) structure of the near "perfect fluid" like sQGP in the critical transition region are integrated into a semi-Quark-Gluon-Monopole Plasma (sQGMP) model lattice-compatibly and implemented into the new CUJET3.0 jet quenching framework. All observables computed from CUJET3.0 are found to be consistent with available data at RHIC and LHC simultaneously. A quantitative connection between the shear viscosity and jet transport parameter is rigorously established within this framework. We deduce the $T=160-600$ MeV dependence of the QGP's $\\eta/s$: its near vanishing value in the near $T_c$ regime is determined by the composition of E and M charges, it increases as $T$ rises, and its high $T$ limit is fixed by color screening scales.
Long wavelength perfect fluidity from short distance jet transport in quark-gluon plasmas
Xu, Jiechen; Liao, Jinfeng; Gyulassy, Miklos
2016-12-01
We build a new phenomenological framework that bridges the long wavelength bulk viscous transport properties of the strongly-coupled quark-gluon plasma (sQGP) and short distance hard jet transport properties in the QGP. The full nonperturbative chromo-electric (E) and chromo-magnetic (M) structure of the near "perfect fluid" like sQGP in the critical transition region are integrated into a semi-Quark-Gluon-Monopole Plasma (sQGMP) model lattice-compatibly and implemented into the new CUJET3.0 jet quenching framework. All observables computed from CUJET3.0 are found to be consistent with available data at RHIC and LHC simultaneously. A quantitative connection between the shear viscosity and jet transport parameter is rigorously established within this framework. We deduce the T = 160 - 600 MeV dependence of the QGP's η / s: its near vanishing value in the near Tc regime is determined by the composition of E and M charges, it increases as T rises, and its high T limit is fixed by color screening scales.
Hard photon production from unsaturated quark-gluon plasma at two-loop level
Energy Technology Data Exchange (ETDEWEB)
Dutta, D. E-mail: ddutta@apsara.barc.ernet.in; Sastry, S.V.S.; Mohanty, A.K.; Kumar, K
2002-11-18
The hard photon production from bremsstrahlung and annihilation with scattering that arise at two-loop level are estimated for a chemically non-equilibrated quark-gluon plasma in the framework of Hard Thermal Loop (HTL) resummed effective field theory. The rate of photon production is found to be suppressed due to unsaturated phase space compared to equilibrated plasma. For an unsaturated plasma, unlike the effective one-loop case, the reduction in the effective two-loop processes is found to be independent of gluon fugacity, due to an additional collinear enhancement arising from the decrease in thermal quark mass but strongly depends on quark and antiquark fugacities. It is also found that the photon production is dominated by bremsstrahlung mechanism, since the phase space suppression is higher for annihilation with scattering, in contrast to the equilibrated plasma where annihilation with scattering dominates the photon production.
In-medium effects in the holographic quark-gluon plasma
Energy Technology Data Exchange (ETDEWEB)
Rust, Felix Christian
2009-08-05
In this dissertation we use the gauge/gravity duality to investigate various properties of strongly coupled gauge theories, which we interpret as models for the quark-gluon plasma (QGP). In particular, we use variants of the D3/D7 setup as an implementation of the top-down approach of connecting string theory with phenomenologically relevant gauge theories. We focus on the effects of finite temperature and finite density on fundamental matter in the holographic quark-gluon plasma, which we model as the N = 2 hypermultiplet in addition to the N=4 gauge multiplet of supersymmetric Yang-Mills theory. As a key ingredient we develop a setup in which we can describe vector meson spectra in the holographic plasma at finite temperature and either baryon or isospin density. The description of vector meson excitations allows for a demonstration of the splitting of their spectrum at finite isospin chemical potential. In the effort to better understand transport processes in the QGP, we then study various diffusion coefficients in the quark-gluon plasma, including their dependence on temperature and particle density. In particular, we perform a simple calculation to obtain the diffusion coefficient of baryon charge and we derive expressions to obtain the isospin diffusion coefficient. Furthermore, we make use of an effective model to study the diffusion behavior of mesons in the plasma by setting up a kinetic model. Finally, we observe the implications of finite temperature and finite baryon or isospin density on the phase structure of fundamental matter in the holographic plasma. As one consequence we find a phase transition in the baryon diffusion coefficient which vanishes at a critical value of the particle density. The critical density we quantify matches the values of the according critical densities previously found in the phase transitions of other quantities. More important, we observe a new phase transition occurring when the isospin chemical potential excesses a
Jet-dilepton conversion from an anisotropic quark-gluon plasma
Mukherjee, Arghya; Roy, Pradip
2016-01-01
We calculate the yield of lepton pair production from jet-plasma interaction where the plasma is anisotropic in momentum space. We compare both the $M$ and $p_T$ distributions from such process with the Drell-Yan contribution. It is observed that the invariant mass distribution of lepton pair from such process dominate over the Drell-Yan up to $3$ GeV at RHIC and up to $10$ GeV at LHC. Moreover, it is found that the contribution from anistropic quark gluon plasma (AQGP) increases marginally compared to the isotropic QGP. In case of $p_T$-distribution we observe an increase by a factor of $3-4$ in the entire $p_T$-range at RHIC for AQGP. However, at LHC the change in the $p_T$-distribution is marginal as compared to the isotropic case.
Equilibration Rates in a Strongly Coupled Nonconformal Quark-Gluon Plasma.
Buchel, Alex; Heller, Michal P; Myers, Robert C
2015-06-26
We initiate the study of equilibration rates of strongly coupled quark-gluon plasmas in the absence of conformal symmetry. We primarily consider a supersymmetric mass deformation within N=2^{*} gauge theory and use holography to compute quasinormal modes of a variety of scalar operators, as well as the energy-momentum tensor. In each case, the lowest quasinormal frequency, which provides an approximate upper bound on the thermalization time, is proportional to temperature, up to a prefactor with only a mild temperature dependence. We find similar behavior in other holographic plasmas, where the model contains an additional scale beyond the temperature. Hence, our study suggests that the thermalization time is generically set by the temperature, irrespective of any other scales, in strongly coupled gauge theories.
Thermalization of mini-jets in a quark-gluon plasma
Directory of Open Access Journals (Sweden)
Iancu Edmond
2016-01-01
Full Text Available We present the complete physical picture for the evolution of a high-energy jet propagating through a weakly-coupled quark-gluon plasma (QGP by analytical and numerical investigation of thermalization of the soft components of the jet. Our results support the following physical picture: the leading particle emits a significant number of mini-jets which promptly evolve via multiple branching and thus degrade into a myriad of soft gluons, with energies of the order of the medium temperature T. Via elastic collisions with the medium constituents, these soft gluons relax to local thermal equilibrium with the plasma over a time scale which is considerably shorter than the typical lifetime of the mini-jet. The thermalized gluons form a tail which lags behind the hard components of the jet. Together with the background QGP, they behave hydrodynamically.
Hard Photon production from unsaturated quark gluon plasma at two loop level
Dutta, D; Mohanty, A K; Kumar, K; Choudhury, R K
2002-01-01
The hard photon productions from bremsstrahlung and annihilation with scattering that arise at two loop level are estimated from a chemically non-equilibrated quark gluon plasma using the frame work of thermal field theory. Although, the rate of photon production is suppressed due to unsaturated phase space, the above suppression is relatively smaller than expected due to an additional collinear enhancement (arise due to decrease in thermal quark mass) as compared to it's equilibrium counterpart. Interestingly, unlike the one loop case, the reduction in the two loop processes are found to be independent of gluon chemical poential, but strongly depends on quark fugacity. It is also found that, since the phase space suppression is highest for annihilation with scattering, the photon production is entirely dominated by bremsstrahlung mechanism at all energies. This is to be contrasted with the case of the equilibrated plasma where annihilation with scattering dominates the photon production particularly at highe...
Thermalization of mini-jets in a quark-gluon plasma
Iancu, Edmond; Wu, Bin
2016-12-01
We present the complete physical picture for the evolution of a high-energy jet propagating through a weakly-coupled quark-gluon plasma (QGP) by analytical and numerical investigation of thermalization of the soft components of the jet. Our results support the following physical picture: the leading particle emits a significant number of mini-jets which promptly evolve via multiple branching and thus degrade into a myriad of soft gluons, with energies of the order of the medium temperature T. Via elastic collisions with the medium constituents, these soft gluons relax to local thermal equilibrium with the plasma over a time scale which is considerably shorter than the typical lifetime of the mini-jet. The thermalized gluons form a tail which lags behind the hard components of the jet. Together with the background QGP, they behave hydrodynamically.
Degrees of Freedom of the Quark Gluon Plasma, tested by Heavy Mesons
Berrehrah, H; Song, T; Ozvenchuck, V; Gossiaux, P B; Werner, K; Bratkovskaya, E; Aichelin, J
2016-01-01
Heavy quarks (charm and bottoms) are one of the few probes which are sensitive to the degrees of freedom of a Quark Gluon Plasma (QGP), which cannot be revealed by lattice gauge calculations in equilibrium. Due to the rapid expansion of the QGP energetic heavy quarks do not come to an equilibrium with the QGP. Their energy loss during the propagation through the QGP medium depends strongly on the modelling of the interaction of the heavy quarks with the QGP quarks and gluons, i.e. on the assuption of the degrees of freedom of the plasma. Here we compare the results of different models, the pQCD based Monte-Carlo (MC@sHQ), the Dynamical Quasi Particle Model (DQPM) and the effective mass approach, for the drag force in a thermalized QGP and discuss the sensitivity of heavy quark energy loss on the properties of the QGP as well as on non-equilibrium dynamics
From gluon topology to chiral anomaly: Emergent phenomena in quark-gluon plasma
Liao, Jinfeng
2016-01-01
Heavy-ion collision experiments at RHIC and the LHC have found a new emergent phase of QCD, a strongly coupled quark-gluon plasma (sQGP) that is distinctively different from either the low temperature hadron phase or the very high temperature weakly coupled plasma phase. Highly nontrivial emergent phenomena occur in such sQGP and two examples will be discussed in this contribution: the magnetic component of sQGP that stems from topologically nontrivial configurations in the gluon sector; and the anomalous chiral transport that arises as macroscopic manifestation of microscopic chiral anomaly in the quark sector. For both examples, their important roles in explaining pertinent heavy-ion data will be emphasized.
Collisional Energy Loss of a Heavy Quark in an Anisotropic Quark-Gluon Plasma
Romatschke, P; Romatschke, Paul; Strickland, Michael
2004-01-01
We compute the leading-order collisional energy loss of a heavy quark propagating through a quark-gluon plasma in which the quark and gluon distributions are anisotropic in momentum space. Following the calculation outlined for QED in an earlier work we indicate the differences encountered in QCD and their effect on the collisional energy loss results. For a 20 GeV bottom quark we show that momentum space anisotropies can result in the collisional heavy quark energy loss varying with the angle of propagation by up to 50%. For low velocity quarks we show that anisotropies result in energy gain instead of energy loss with the energy gain focused in such a way as to accelerate particles along the anisotropy direction thereby reducing the momentum-space anisotropy. The origin of this negative energy loss is explicitly identified as being related to the presence of plasma instabilities in the system.
From gluon topology to chiral anomaly: Emergent phenomena in quark-gluon plasma
Liao, Jinfeng
2017-01-01
Heavy-ion collision experiments at RHIC and the LHC have found a new emergent phase of QCD, a strongly coupled quark-gluon plasma (sQGP) that is distinctively different from either the low temperature hadron phase or the very high temperature weakly coupled plasma phase. Highly nontrivial emergent phenomena occur in such sQGP and two examples will be discussed in this contribution: the magnetic component of sQGP that stems from topologically nontrivial configurations in the gluon sector; and the anomalous chiral transport that arises as macroscopic manifestation of microscopic chiral anomaly in the quark sector. For both examples, their important roles in explaining pertinent heavy-ion data will be emphasized.
Directory of Open Access Journals (Sweden)
Pari Sharareh Mehrabi
2016-01-01
Full Text Available The “Laplace Transform Method” is used to solve the Fokker-Plank equation for finding the time evolution of the heavy quarks distribution functions such as charm and bottom in quark gluon plasma. These solutions will lead us to calculation of nuclear suppression factor RAA. The results have good agreement with available experiment data from the PHENIX collaboration.
Properties of Non-Conformal Quark Gluon Plasma of Holographic QCD Models from Compactified D4 Branes
Naji, J.
2016-08-01
In this article, we obtain some thermodynamics quantities of non-conformal gluonic matter. We extract specific heat, enthalpy and equation of state in terms of the temperature. Using transport properties we find important quantities of corresponding quark gluon plasma like drag force and jet-quenching.
Collective phenomena in the non-equilibrium quark-gluon plasma
Energy Technology Data Exchange (ETDEWEB)
Schenke, Bjoern Peter
2008-07-03
In this work we study the non-equilibrium dynamics of a quark-gluon plasma, as created in heavy-ion collisions. We investigate how big of a role plasma instabilities can play in the isotropization and equilibration of a quark-gluon plasma. In particular, we determine, among other things, how much collisions between the particles can reduce the growth rate of unstable modes. This is done both in a model calculation using the hard-loop approximation, as well as in a real-time lattice simulation combining both classical Yang-Mills-fields as well as inter-particle collisions. The new extended version of the simulation is also used to investigate jet transport in isotropic media, leading to a cutoff-independent result for the transport coefficient q. The precise determination of such transport coefficients is essential, since they can provide important information about the medium created in heavy ion collisions. In anisotropic media, the effect of instabilities on jet transport is studied, leading to a possible explanation for the experimental observation that high-energy jets traversing the plasma perpendicular to the beam axis experience much stronger broadening in rapidity than in azimuth. The investigation of collective modes in the hard-loop limit is extended to fermionic modes, which are shown to be all stable. Finally, we study the possibility of using high energy photon production as a tool to experimentally determine the anisotropy of the created system. Knowledge of the degree of local momentum-space anisotropy reached in a heavy-ion collision is essential for the study of instabilities and their role for isotropization and thermalization, because their growth rate depends strongly on the anisotropy. (orig.)
Dileptons from a Chemically Equilibrating Quark-Gluon Plasma at Finite Baryon Density
Institute of Scientific and Technical Information of China (English)
GUAN Na-Na; HE Ze-Jun; LONG Jia-Li; CAI Xiang-Zhou
2008-01-01
We perform a complete calculation for the delepton production from the processes q(q-) →l(l-), Compton-like (qg→ql(l-),(q-)g→ql(l-)), q(q-)→gl(l-), gluon fusion g(g-)→c(c-), annihilation q(q-)→c(c-) as well as multiple scattering of quarks in a chemically equilibrating quark-gluon plasma system at finite baryon density. It is found that quark-antiquark annihilation,Compton-like, gluon fusion and multiple scattering of quarks give important contribution. Moreover, the increase of the quark phase life-time with increasing initial quark chemical potential makes the dilepton yield as an increasing function of the initial quark chemical potential.
Jet-Medium Interactions at NLO in a Weakly-Coupled Quark-Gluon Plasma
Ghiglieri, Jacopo; Teaney, Derek
2015-01-01
We present an extension to next-to-leading order in the strong coupling constant $g$ of the AMY effective kinetic approach to the energy loss of high momentum particles in the quark-gluon plasma. At leading order, the transport of jet-like particles is determined by elastic scattering with the thermal constituents, and by inelastic collinear splittings induced by the medium. We reorganize this description into collinear splittings, high-momentum-transfer scatterings, drag and diffusion, and particle conversions (momentum-preserving identity-changing processes). We show that this reorganized description remains valid to NLO in $g$, and compute the appropriate modifications of the drag, diffusion, particle conversion, and inelastic splitting coefficients. In addition, a new kinematic regime opens at NLO for wider-angle collinear bremsstrahlung. These semi-collinear emissions smoothly interpolate between the leading order high-momentum-transfer scatterings and collinear splittings. To organize the calculation, w...
On the Variational method for LPM Suppression of Photon Emission from Quark-Gluon Plasma
Sastry, S
2002-01-01
The photon emission rates from the quark gluon plasma have been studied considering LPM suppression effects. The integral equation for the transverse vector function (f(p)) that consists of multiple scattering effects has been solved using self-consistent iterations method. Empirical fits to the peak positions of the distributions from iteration method have been obtained for bremsstrahlung and annihilation with scattering (AWS) processes. The variational approach for f(p) calculation has been simplified considerably making some assumptions. Using this method, the photon emission rates at finite baryon density have been estimated. The LPM suppression factors for bremsstrahlung and annihilation with scattering (AWS) processes have been obtained as a function of photon energy and baryon density. The effect of baryon density has been shown to be rather weak and the suppression factors are similar to the zero density case. The suppression factors for AWS processes can be taken at zero density, whereas the bremsstr...
The quark gluon plasma equation of state and the expansion of the early Universe
Energy Technology Data Exchange (ETDEWEB)
Sanches, S.M.; Navarra, F.S.; Fogaça, D.A., E-mail: david@if.usp.br
2015-05-15
Our knowledge of the equation of state of the quark gluon plasma has been continuously growing due to the experimental results from heavy ion collisions, due to recent astrophysical measurements and also due to the advances in lattice QCD calculations. The new findings about this state may have consequences on the time evolution of the early Universe, which can be estimated by solving the Friedmann equations. The solutions of these equations give the time evolution of the energy density and also of the temperature in the beginning of the Universe. In this work we compute the time evolution of the QGP in the early Universe, comparing several equations of state, some of them based on the MIT bag model (and on its variants) and some of them based on lattice QCD calculations. Among other things, we investigate the effects of a finite baryon chemical potential in the evolution of the early Universe.
The Quark-Gluon Plasma Equation of State and the Generalized Uncertainty Principle
Directory of Open Access Journals (Sweden)
L. I. Abou-Salem
2015-01-01
Full Text Available The quark-gluon plasma (QGP equation of state within a minimal length scenario or Generalized Uncertainty Principle (GUP is studied. The Generalized Uncertainty Principle is implemented on deriving the thermodynamics of ideal QGP at a vanishing chemical potential. We find a significant effect for the GUP term. The main features of QCD lattice results were quantitatively achieved in case of nf=0, nf=2, and nf=2+1 flavors for the energy density, the pressure, and the interaction measure. The exciting point is the large value of bag pressure especially in case of nf=2+1 flavor which reflects the strong correlation between quarks in this bag which is already expected. One can notice that the asymptotic behavior which is characterized by Stephan-Boltzmann limit would be satisfied.
Deconfining Phase Transition to a Quark-Gluon Plasma in Different SU(3) Color Representations
Mezouar, K.; Ait El Djoudi, A.; Ghenam, L.
2016-10-01
For a statistical description of the quark gluon plasma (QGP) considering its internal symmetry, we calculate its partition function using the group theoretical projection method. We project out the partition function of a QGP consisting of gluons, massless up and down quarks, and massive strange quarks onto the singlet representation of the SU(3) color group, as well as onto the color octet and the color 27-plet representations. A comparison of these color representations is done, by studying their effects on the behavior of some thermodynamical quantities characterizing the mixed hadronic gas-QGP system undergoing a thermal deconfining phase transition on one side, and on the free energy during the formation of a QGP droplet from the hot hadronic gas on another side.
Pion interferometry at RHIC: porobing a thermalized quark-gluon plasma?
Soff, S; Bass, S A; Dumitru, A
2001-04-30
We calculate the Gaussian radius parameters of the pion-emitting source in high-energy heavy-ion collisions, assuming a first-order phase transition from a thermalized quark-gluon plasma (QGP) to a gas of hadrons. Such a model leads to a very long-lived dissipative hadronic rescattering phase which dominates the properties of the two-pion correlation functions. The radii are found to depend only weakly on the thermalization time tau(i), the critical temperature Tc (and thus the latent heat), and the specific entropy of the QGP. The model calculations suggest a rapid increase of R(out)/R(side) as a function of KT if a thermalized QGP were formed.
Nonperturbative heavy-quark diffusion in the quark-gluon plasma.
van Hees, H; Mannarelli, M; Greco, V; Rapp, R
2008-05-16
We evaluate heavy-quark (HQ) transport properties in a quark-gluon plasma (QGP) within a Brueckner many-body scheme employing interaction potentials extracted from thermal lattice QCD. The in-medium T matrices for elastic charm- and bottom-quark scattering off light quarks in the QGP are dominated by attractive meson and diquark channels which support resonance states up to temperatures of ~1.5T(c). The resulting drag coefficient increases with decreasing temperature, contrary to expectations based on perturbative QCD scattering. Employing relativistic Langevin simulations we compute HQ spectra and elliptic flow in sqrt[s(NN)]=200 GeV Au-Au collisions. A good agreement with electron decay data supports our nonperturbative computation of HQ diffusion, indicative for a strongly coupled QGP.
Heavy-quark transport coefficients in a hot viscous quark-gluon plasma medium
Das, Santosh K; Alam, Jan-e
2012-01-01
The heavy-quark (HQ) transport coefficients have been estimated for a viscous quark-gluon plasma medium, utilizing a recently proposed quasi-particle description based on realistic QGP equation of state (EoS). Interactions entering through the equation of state significantly suppress the temperature dependence of the drag coefficient of QGP as compared to that of an ideal system of quarks and gluons. Inclusion of shear and bulk viscosities through the corrections to the thermal phase space factors of the bath particles alters the magnitude of the drag coefficient and the enhancement is significant at lower temperatures. The competition between the effects of realistic EoS and dissipative corrections through phase space factor the former eventually dictate how the drag coefficient would behave as a function of temperature, and how much quantitatively digress from the ideal case. The observations suggest significant impact of both the realistic equation of state, and the viscosities, on the HQs transport at RHI...
Flow at the SPS and RHIC as a Quark Gluon Plasma Signature
Teaney, D; Shuryak, E V
2001-01-01
Radial and elliptic flow in non-central heavy ion collisions can constrain the effective Equation of State(EoS) of the excited nuclear matter. To this end, a model combining relativistic hydrodynamics and a hadronic transport code(RQMD [17]) is developed. For an EoS with a first order phase transition, the model reproduces both the radial and elliptic flow data at the SPS. With the EoS fixed from SPS data, we quantify predictions at RHIC where the Quark Gluon Plasma(QGP) pressure is expected to drive additional radial and elliptic flow. Currently, the strong elliptic flow observed in the first RHIC measurements does not conclusively signal this nascent QGP pressure. Additional measurements are suggested to pin down the EoS.
Flow at the SPS and RHIC as a Quark-Gluon Plasma Signature
Teaney, D.; Lauret, J.; Shuryak, E. V.
2001-05-01
Radial and elliptic flow in noncentral heavy-ion collisions can constrain the effective equation of state (EOS) of the excited nuclear matter. To this end, a model combining relativistic hydrodynamics and a hadronic transport code [Sorge, Phys. Rev. C 52, 3291 (1995)] is developed. For an EOS with a first-order phase transition, the model reproduces both the radial and elliptic flow data at the SPS. With the EOS fixed from SPS data, we quantify predictions at RHIC where the quark-gluon plasma (QGP) pressure is expected to drive additional radial and elliptic flows. Currently, the strong elliptic flow observed in the first RHIC measurements does not conclusively signal this nascent QGP pressure.
Thermodynamics of the Quark-Gluon Plasma within a T-matrix approach
Lacroix, Gwendolyn; Buisseret, Fabien
2015-01-01
The strongly-coupled phase of the quark-gluon plasma (QGP) is studied here by resorting to a $T$-matrix formulation in which the medium is seen as a non-ideal gas of quasiparticles (quarks, antiquarks and gluons) interacting nonpertubatively. In the temperature range under study, (1-5) $T_c$, where $T_c$ is the temperature of deconfinement, the interactions are expected to be strong enough to generate bound states. The dissociation temperature of such binary bound states is thus computed here. The more the quasiparticles involved in the binary system are heavy, the more the bound state is likely to survive significantly above $T_c$. Then, the QGP equations of state at zero and small baryonic potential are computed for $N_f = 2$ and $N_f = 2 + 1$ by resorting to the Dashen, Ma and Bernstein formulation of statistical mechanics. Comparisons with current lattice QCD data are presented.
Criterion for reducible hydrodynamic equations of baryon-rich quark-gluon plasma
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
Besides the state equation there exists another cubic algebraic equation about μf in the form of μ3f + Pμf + q = 0, which relates parameters, temperature T, chemical potential μf, and net quark number nff (flavor f) for a baryon-rich quark-gluon plasma (QGP). A criterion may be acquired simply according to Cardan formula of the solution of the above equation, which gives naturally a condition: if n 《 27rT3/3/ , one may approximately use the conservation of specific entropy, and then the set of hydrodynamic equation of baryon-rich QGP may be reduced to the sct of hydrodynamic equation for baryon-free QGP.
Thermalization of the quark-gluon plasma and dynamical formation of Bose-Einstein Condensate
Liao, Jinfeng
2012-01-01
We report recent progress on understanding the thermalization of the quark-gluon plasma during the early stage in a heavy ion collision. The initially high overpopulation in the pre-equilibrium gluonic matter (``glasma'') is shown to play a crucial role. The strongly interacting nature (and thus fast evolution) naturally arises as an {\\em emergent property} of this pre-equilibrium matter where the intrinsic coupling is weak but the highly occupied gluon states coherently amplify the scattering. A possible transient Bose-Einstein Condensate is argued to form dynamically on a rather general ground. We develop the kinetic approach for describing this highly overpopulated system and find approximate scaling solutions as well as numerically study the onset of condensation. Finally we discuss possible phenomenological implications.
Collective modes of an anisotropic quark-gluon plasma induced by relativistic jets
Mandal, Mahatsab
2012-01-01
We discuss the characteristics of collective modes induced by relativistic jets in an anisotropic quark-gluon plasma(AQGP). Assuming a tsunami-like initial jet distribution, it is found that the dispersion relations for both the stable and unstable modes are modified substantially due to the passage of jet compared to the case when there is no jet. It has also been shown that the growth rate of instability first increases compared to the no jet case and then completely turned into damping except the case when the jet velocity is perpendicular to the wave vector in which case the instability always grows. Thus, the introduction of the jet in the AQGP, in general, might to faster isotropization for the special case when the wave vector is parallel to the anisotropy axis.
Dijet induced collective modes in an anisotropic quark-gluon plasma
Mandal, Mahatsab
2012-01-01
We discuss the collective modes due to the propagation of two oppositely moving relativistic jets (dijet) in an anisotropic quark-gluon plasma(AQGP) and compare the results with the case of single jet propagation. Assuming a tsunami-like initial jet distribution, it is found that the dispersion relations for both the stable and unstable modes are altered significantly due to the passage of dijet compared to the case of single jet propagation. It has also been shown that the growth rate of instability, due to introduction of dijet in the system, increases compared to the case of single jet case. As in the case of single jet propagation, the instability always grows when the jet velocity is perpendicular to the wave vector. We, thus, argue that the introduction of dijet in the AQGP, in general, leads to faster isotropization (than single jet propagation) for the special case when the wave vector is parallel to the anisotropy axis.
Complex suppression patterns distinguish between major energy loss effects in Quark-Gluon Plasma
Djordjevic, Magdalena
2015-01-01
Interactions of high momentum partons with Quark-Gluon Plasma created in relativistic heavy-ion collisions provide an excellent tomography tool for this new form of matter. Recent measurements for charged hadrons and unidentified jets at the LHC show an unexpected flattening of the suppression curves at high momentum, exhibited when either momentum or the collision centrality is changed. Furthermore, a limited data available for B probes indicate a qualitatively different pattern, as nearly the same flattening is exhibited for the curves corresponding to two opposite momentum ranges. We here show that the experimentally measured suppression curves are well reproduced by our theoretical predictions, and that the complex suppression patterns are due to an interplay of collisional, radiative energy loss and the dead-cone effect. Furthermore, for B mesons, we predict that the uniform flattening of the suppression indicated by the limited dataset is in fact valid across the entire span of the momentum ranges, whic...
The sound produced by a fast parton in the quark-gluon plasma is a "crescendo"
Neufeld, R B
2009-01-01
We calculate the total energy deposited into the medium per unit length by fast partons traversing a quark-gluon plasma. The medium excitation due to collisions is taken to be given by the well known expression for the collisional drag force. The radiative energy loss of the parton contributes to the energy deposition because each radiated gluon acts as an additional source of collisional energy loss in the medium. We derive a differential equation which governs how the spectrum of radiated gluons is modified when this energy loss is taken into account. This modified spectrum is then used to calculate the additional energy deposition due to the interactions of radiated gluons with the medium. Numerical results are presented for the medium response for the case of two energetic back-to-back partons created in a hard interaction.
The sound generated by a fast parton in the quark-gluon plasma is a crescendo
Neufeld, R B
2009-01-01
The total energy deposited into the medium per unit length by a fast parton traversing a quark-gluon plasma is calculated. We take the medium excitation due to collisions to be given by the well known expression for the collisional drag force. The parton's radiative energy loss contributes to the energy deposition because each radiated gluon acts as an additional source of collisional energy loss in the medium. In our model, this leads to a length dependence on the differential energy loss due to the interactions of radiated gluons with the medium. The final result, which is a sum of the primary and the secondary contributions, is then treated as the coefficient of a local hydrodynamic source term. Results are presented for energy density wave induced by two fast, back-to-back partons created in an initial hard interaction.
Sound Produced by a Fast Parton in the Quark-Gluon Plasma is a ``Crescendo''
Neufeld, R. B.; Müller, B.
2009-07-01
We calculate the total energy deposited into the medium per unit length by fast partons traversing a quark-gluon plasma. The medium excitation due to collisions is taken to be given by the well-known expression for the collisional drag force. The radiative energy loss of the parton contributes to the energy deposition because each radiated gluon acts as an additional source of collisional energy loss in the medium. We derive a differential equation which governs how the spectrum of radiated gluons is modified when this energy loss is taken into account. This modified spectrum is then used to calculate the additional energy deposition due to the interactions of radiated gluons with the medium. Numerical results are presented for the medium response for the case of two energetic back-to-back partons created in a hard interaction.
Sound produced by a fast parton in the quark-gluon plasma is a "crescendo".
Neufeld, R B; Müller, B
2009-07-24
We calculate the total energy deposited into the medium per unit length by fast partons traversing a quark-gluon plasma. The medium excitation due to collisions is taken to be given by the well-known expression for the collisional drag force. The radiative energy loss of the parton contributes to the energy deposition because each radiated gluon acts as an additional source of collisional energy loss in the medium. We derive a differential equation which governs how the spectrum of radiated gluons is modified when this energy loss is taken into account. This modified spectrum is then used to calculate the additional energy deposition due to the interactions of radiated gluons with the medium. Numerical results are presented for the medium response for the case of two energetic back-to-back partons created in a hard interaction.
Turbulent chromo-fields and thermal particle production in quark-gluon plasma medium
Chandra, Vinod
2016-01-01
The Weibel type instabilities appear in the expanding quark-gluon plasma (QGP) in relativistic heavy-ion collisions, due to the presence of momentum-space anisotropy, are responsible for the generation of the turbulent color fields. The ensemble averaged (ensemble of the turbulent fields) effective diffusive Vlasov equation, for the modified momentum distribution functions of the quarks and gluons encodes the physics of such instability and leads to the anomalous transport process in the QGP medium. In the present case, the solution of the linearized transport equation for the modified momentum distribution functions has been served as the modeling for the non-equilibrium momentum distribution functions for the QGP degrees of freedom. The strength of anisotropy has been related to a phenomenologically obtained jet-quenching parameter, $\\hat{q}$. We have computed the contribution of these anisotropic terms to the thermal dilepton production rates. The production rate has been seen to be appreciably sensitive t...
Initial energy density of quark-gluon plasma in relativistic heavy-ion collisions
Energy Technology Data Exchange (ETDEWEB)
Wong, C.Y.
1984-01-01
Recently, there has been considerable interest in the central rapidity region of highly relativistic heavy-ion collisions. Such an interest stems from the possibility of creating hadron matter of high energy density which may exceed the critical energy density for a phase transition between ordinary confined matter and the unconfined quark-gluon plasma. The experimental searches and identification of the quark-gluon plasma may provide a new insight into the question of quark confinement. The estimate of the initial energy density is quite uncertain. The initial energy density is nonetheless an important physical quantity. It is one of the factors which determines whether the produced matter can undergo phase transition or not. The energy density has been estimated previously by using the color neutralization model of Brodsky et al. However, the color neutralization model gives a central rapidity multiplicity in heavy-ion collision too low by a factor of two. For this reason, we wish to obtain a better estimate of the energy density (in the central rapidity region). As is well known, a simple Glauber-type multiple collision model can reproduce the total multiplicity and multiplicity plateau near the central rapidity region to within 30%. The simple multiple collision model has an approximate validity as a gross description of the reaction process. We shall adopt a semiempirical approach. Using the multiple collision model and the thickness function of Glauber, we obtain analytical functional form for all the quantities in question. A single parameter, r/sub rms/, is adjusted to fit the experimental central rapidity multiplicity data. The semi-empirical results provide a useful tool to extrapolate to the unknown central rapidity region of heavy-ion collisions.
Real time observables for the quark-gluon plasma from the lattice
Energy Technology Data Exchange (ETDEWEB)
Schaefer, Christian
2014-07-01
In this thesis we studied real time quantities and processes of the quark-gluon plasma. We employed the fundamental theory of QCD allowing for predictions from first principles. Treating QCD on the lattice enabled us to access non-perturbative regimes and for the very first time we computed a hydrodynamic transport coefficient without having to resort to maximum entropy methods or functional input. Furthermore we established a semi-classical formulation of QCD that we applied to investigate the effects of dynamic fermions as well as of using the correct colour group of QCD, SU(3), on the isotropization process of the quark-gluon plasma. In this work we have calculated the second order hydrodynamic transport coefficient κ for the Yang-Mills plasma using lattice perturbation theory and Monte Carlo simulations. From calculations both in strong and weak coupling limits, we expect a temperature dependence of κ∝T{sup 2}. In the investigated temperature range 2T{sub c}
On The Existence of a Holographic Description of the LHC Quark-Gluon Plasmas
McInnes, Brett
2016-01-01
Peripheral collisions of heavy ions can give rise to extremely intense magnetic fields. It has been suggested that these fields might invalidate the holographic description of the corresponding quark-gluon plasmas, assuming that these can be modelled by strongly coupled field theories. In the case of the plasmas produced in collisions at the RHIC facility (including in the beam energy scans), it is known how to deal with this problem: one has to take into account the large angular momenta generated in these plasmas, and the effects of the baryonic chemical potential. But this does not work for the plasmas produced in peripheral collisions at the LHC. However, these results neglect some (less significant) aspects of bulk physics; could it be that the problem is resolved by taking into account these lower-order effects? Here we use a bulk dilatonic field (fully compatible with boundary data, as well as with the asymptotically AdS character of the bulk geometry) as a model of these effects, and show that this is...
"Chemical" composition of the Quark-Gluon Plasma in relativistic heavy-ion collisions
Scardina, F; Plumari, S; Greco, V
2012-01-01
We study the evolution of the quark-gluon composition of the plasma created in ultra-Relativistic Heavy Ion Collisions (uRHIC's) employing a partonic transport theory that includes both elastic and inelastic collisions plus a mean fields dynamics associated to the widely used quasi-particle model. The latter, able to describe lattice QCD thermodynamics, implies a "chemical" equilibrium ratio between quarks and gluons strongly increasing as $T\\rightarrow T_c$, the phase transition temperature. Accordingly we see in realistic simulations of uRHIC's a rapid evolution from a gluon dominated initial state to a quark dominated plasma close to $T_c$. The quark to gluon ratio can be modified by about a factor of $\\sim 20$ in the bulk of the system and appears to be large also in the high $p_T$ region. We discuss how this aspect, often overflown, can be essential for a quantitative study of several key issues in the QGP physics: shear viscosity, jet quenching, quarkonia suppression. Furthemore a bulk plasma made by mo...
Evolution of Baryon Rich Quark-Gluon Plasma and radiation of Single Photons
Sastry, S; Mohanty, A K; Srivastava, D K
2002-01-01
The (3+1) dimensional expansion of the quark gluon plasma (QGP) produced at finite baryon density has been studied using relativistic hydrodynamical approach. The pressure functional of the equation of state (EoS) has been determined for the interacting nuclear matter with mesons exchange. The EoS has been used to solve hydrodynamical equations using RHLLE algorithm. The space time expansion of the plasma has been studied for the cases of SPS energy and RHIC energy both at finite baryon density and for a hypothetical case of SPS energy at zero baryon density. The space-time evolution is slowed and the life times of QGP and mixed phases are shortened in the presence of finite baryon density. The space time integrated total photon yields have been estimated by convoluting the static emission rates with the space time expansion of the plasma. It has been shown that the total photon yield at zero rapidity is not significantly affected by the baryon density for SPS energy. The total photon yield is unaffected by t...
Institute of Scientific and Technical Information of China (English)
LONG Jia-Li; HE Ze-Jun; MA Yu-Gang
2006-01-01
@@ We investigate hard photon production of the near-collinear bremsstrahlung and a new process called the inelastic pair annihilation, fully including the LPM effect, in a chemically equilibrating quark-gluon plasma at finite baryon density, and find that the effect of the system evolution on the photon production and large contribution of the bremsstrahlung make the total photon yield of the two processes as a strongly increasing function of the initial quark chemical potential.
Energy loss, equilibration, and thermodynamics of a baryon rich strongly coupled quark-gluon plasma
Rougemont, Romulo; Finazzo, Stefano; Noronha, Jorge
2015-01-01
Lattice data for the QCD equation of state and the baryon susceptibility near the crossover phase transition (at zero baryon density) are used to determine the input parameters of a 5-dimensional Einstein-Maxwell-Dilaton holographic model that provides a consistent holographic framework to study both equilibrium and out-of-equilibrium properties of a hot and {\\it baryon rich} strongly coupled quark-gluon plasma (QGP). We compare our holographic equation of state computed at nonzero baryon chemical potential, $\\mu_B$, with recent lattice calculations and find quantitative agreement for the pressure and the speed of sound for $\\mu_B \\leq 400$ MeV. This holographic model is used to obtain holographic predictions for the temperature and $\\mu_B$ dependence of the drag force and the Langevin diffusion coefficients associated with heavy quark jet propagation as well as the jet quenching parameter $\\hat{q}$ and the shooting string energy loss of light quarks in the dense plasma. We find that the energy loss of heavy ...
Empirical Emission Functions for LPM Suppression of Photon Emission from Quark-Gluon Plasma
Sastry, S
2003-01-01
The LPM suppression of photon emission rates from the quark gluon plasma have been studied at different physical conditions of the plasma given by temperature and chemical potentials.The integral equation for the transverse vector function (f(p_t)) consisting of multiple scattering effects is solved for the parameter set {p,k,kappa,T}, for bremsstrahlung and AWS processes. The peak positions of these distributions depend only on the dynamical variable x=(T/kappa)|1/p-1/(p+k)|. Integration over these distributions multiplied by x^2 factor also depends on this variable x,leading to a unique global emission function g(x) for all parameters. Empirical fits to this dimensionless emission function, g(x), are obtained. The photon emission rate calculations with LPM suppression effects reduce to one dimensional integrals involving folding over the empirical g(x) function with appropriate distribution functions and the kinematic factors. Using this approach, the suppression factors for both bremsstrahlung and AWS have...
Korteveg-de Vries solitons in a cold quark-gluon plasma
Fogaça, D. A.; Navarra, F. S.; Ferreira Filho, L. G.
2011-09-01
The relativistic heavy ion program developed at RHIC and now at LHC motivated a deeper study of the properties of the quark-gluon plasma (QGP) and, in particular, the study of perturbations in this kind of plasma. We are interested on the time evolution of perturbations in the baryon and energy densities. If a localized pulse in baryon density could propagate throughout the QGP for long distances preserving its shape and without loosing localization, this could have interesting consequences for relativistic heavy ion physics and for astrophysics. A mathematical way to prove that this can happen is to derive (under certain conditions) from the hydrodynamical equations of the QGP a Korteveg-de Vries (KdV) equation. The solution of this equation describes the propagation of a KdV soliton. The derivation of the KdV equation depends crucially on the equation of state (EOS) of the QGP. The use of the simple MIT bag model EOS does not lead to KdV solitons. Recently we have developed an EOS for the QGP which includes both perturbative and nonperturbative corrections to the MIT one and is still simple enough to allow for analytical manipulations. With this EOS we were able to derive a KdV equation for the cold QGP.
Dilepton production by dynamical quasiparticles in the strongly interacting quark gluon plasma
Linnyk, O
2010-01-01
The dilepton production by the constituents of the strongly interacting quark-gluon-plasma (sQGP) is addressed. In order to make quantitative predictions at realistically low plasma temperatures (O(T_c)), experimentally relevant low dilepton mass (O(1 GeV)) and strong coupling (alphaS=0.5-1), we take into account not only the higher order pQCD reaction mechanisms, but also the non-perturbative spectral functions (off-shellness) and self-energies of the quarks, anti-quarks and gluons thus going beyond the leading twist. For this purpose, our calculations utilize parametrizations of the non-perturbative propagators for quarks and gluons provided by the dynamical quasi-particle model (DQPM) matched to reproduce lattice data. The DQPM describes QCD properties in terms of single-particle Green's functions (in the sense of a two-particle irreducible approach) and leads to the notion of the constituents of the sQGP being effective quasiparticles, which are massive and have broad spectral functions (due to large inte...
Probing the Quark Gluon Plasma with Heavy Flavours: recent results from ALICE
CERN. Geneva
2017-01-01
The study of open heavy-flavour physics allows us to investigate the key properties of the Quark-Gluon Plasma (QGP) and the microscopic processes ongoing in the medium produced in heavy-ion collisions at relativistic energies. Heavy quarks are produced in the early stages of heavy-ion collisions and their further production and annihilation rates in the medium are expected to be very small throughout the evolution of the system. Therefore, they serve as penetrating probes that traverse the hot and dense medium, interact with the partonic constituents of the plasma and lose energy. Understanding the interactions of heavy quarks with the medium requires precise measurements over a wide momentum range in heavy-ion collisions, but also in smaller systems like pp collisions, which also test next-to-leading order perturbative QCD calculations, and proton-nucleus collisions, which are sensitive to Cold Nuclear Matter effects (CNM), such as the modification of the parton distribution functions of nuclei, and parton ...
Recent Results on Soft Probes of the Quark-Gluon Plasma from the ATLAS Experiment at the LHC
Przybycien, M; The ATLAS collaboration
2014-01-01
Measurements of low-pT (< 5 GeV) particle production have provided valuable insight on the production and evolution of the quark-gluon plasma in Pb+Pb collisions at the LHC. In particular, measurements of elliptic and higher order collective flow imprinted on the azimuthal angle distributions of low-pT particles directly probe the strongly-coupled dynamics of the quark-gluon plasma and test hydrodynamic model descriptions of its evolution. The large acceptance of detectors like ATLAS has made it possible to measure flow event-by-event and to determine the correlations between different harmonics. Recent measurements of low-pT particle production and multi-particle correlations in proton-lead collisions have shown features similar to the collective flow observed in Pb+Pb collisions. Results will be presented from a variety of single and multi-particle measurements in Pb+Pb and proton-Pb collisions that probe the collective dynamics of the quark-gluon plasma and possibly provide evidence for collectivity in ...
Soft Probes of the Quark-Gluon Plasma with ALICE at LHC
Vernet, Renaud
2009-01-01
The Large Hadron Collider (LHC) should start its activity of data taking by the end of summer 2009, and will provide beams of p-p and Pb-Pb at colliding energies up to 14 TeV and 5.5 ATeV respectively. The Pb-Pb heavy-ion program aims at reaching the necessary conditions to create a deconfined state of partons, the Quark-Gluon Plasma (QGP), whose study is one of the most exciting physics topics to be explored thanks to the possibilites offered by this new-generation accelerator. In particular, the "soft" observables related to low and intermediate pT processes, will shed light on many fundamental properties of the system, such as thermodynamic parameters, chemical composition, expansion velocity etc. The p-p collisions will be of great interest as well, since they will serve as an essential reference for heavy ions. ALICE (A Large Ion Collider Experiment) is the LHC experiment dedicated to the study of the QGP. Its large acceptance and low magnetic field make it particularly suited for the study of soft pheno...
Are direct photons a clean signal of a thermalized quark gluon plasma?
Boyanovsky, D
2003-01-01
Direct photon production from a quark gluon plasma (QGP) in thermal equilibrium is studied directly in real time. In contrast to the usual S-matrix calculations, the real time approach is valid for a QGP that formed and reached LTE a short time after a collision and of finite lifetime ($\\sim 10-20 \\mathrm{fm}/c$ as expected at RHIC or LHC). We point out that during such finite QGP lifetime the spectrum of emitted photons carries information on the initial state. There is an inherent ambiguity in separating the virtual from the observable photons during the transient evolution of the QGP. We propose a real time formulation to extract the photon yield which includes the initial stage of formation of the QGP parametrized by an effective time scale of formation $\\Gamma^{-1}$. This formulation coincides with the S-matrix approach in the infinite lifetime limit. It allows to separate the virtual cloud as well as the observable photons emitted during the pre- equilibrium stage from the yield during the QGP lifetime....
Suppression of Baryon Diffusion and Transport in a Baryon Rich Strongly Coupled Quark-Gluon Plasma.
Rougemont, Romulo; Noronha, Jorge; Noronha-Hostler, Jacquelyn
2015-11-13
Five dimensional black hole solutions that describe the QCD crossover transition seen in (2+1)-flavor lattice QCD calculations at zero and nonzero baryon densities are used to obtain predictions for the baryon susceptibility, baryon conductivity, baryon diffusion constant, and thermal conductivity of the strongly coupled quark-gluon plasma in the range of temperatures 130 MeV≤T≤300 MeV and baryon chemical potentials 0≤μ(B)≤400 MeV. Diffusive transport is predicted to be suppressed in this region of the QCD phase diagram, which is consistent with the existence of a critical end point at larger baryon densities. We also calculate the fourth-order baryon susceptibility at zero baryon chemical potential and find quantitative agreement with recent lattice results. The baryon transport coefficients computed in this Letter can be readily implemented in state-of-the-art hydrodynamic codes used to investigate the dense QGP currently produced at RHIC's low energy beam scan.
Hadron production in relativistic heavy ion interactions and the search for the quark-gluon plasma
Energy Technology Data Exchange (ETDEWEB)
Tannenbaum, M.J.
1989-12-01
The course starts with an introduction, from the experimentalist's point of view, of the challenge of measuring Relativistic Heavy Ion interactions. A review of some theoretical predictions for the expected signatures of the quark gluon plasma will be made, with a purpose to understand how they relate to quantities which may be experimentally measured. A short exposition of experimental techniques and details is given including charged particles in matter, momentum resolution, kinematics and Lorentz Transformations, calorimetry. Principles of particle identification including magnetic spectrometers, time of flight measurement. Illustrations using the E802 spectrometer and other measured results. Resolution smearing of spectra, and binning effects. Parent to daughter effects in decay, with {pi}{sup 0} {yields} {gamma} {gamma} as an example. The experimental situation from the known data in p -- p collisions and proton-nucleus reactions is reviewed and used as a basis for further discussions. The Cronin Effect'' and the Seagull Effect'' being two arcana worth noting. Then, selected experiments from the BNL and CERN heavy ion programs are discussed in detail. 118 refs., 45 figs.
On magnetization of quark-gluon plasma at the LHC experiment energies
Skalozub, V
2016-01-01
Large scale chromomagnetic, B_3, B_8, and usual magnetic,H, fields have to be generated in QCD after the deconfinement phase transition (DPT) at temperatures T larger than deconfinement temperature T_d. The two former fields are created spontaneously due to asymptotic freedom of gluon intaractions. Whereas H is produced due to either the feature of quarks to possess both electric and color charges or a vacuum polarization in this case. At the polarization, the vacuum quark loops mix the external fields. As a result, B_3, B_8 become the sources generating H. The latter field appears at $T$ much lower than the electroweak phase transition temperature T_ew. This mechanism should exhibit itself at the LHC experiments on heavy ion collisions. It operates at the one-loop diagram level for an effective potential. The created fields are temperature dependent and occupying the macroscopic volume of quark-gluon plasma. The magnetization influences different processes and may serve as a signal for the DPT.
Quark-gluon plasma effects on hadrons in AdS/QCD
Bartz, Sean; Jacobson, Theodore
2016-09-01
The AdS/CFT correspondence has succeeded in describing qualitatively many features of non-perturbative QCD. An approach known as bottom-up AdS/QCD uses a dilaton field to break conformal symmetry, introducing confinement and describing well the features of hadronic spectra at zero temperature. Introducing a black hole into the AdS metric allows for the study of thermodynamic properties of QCD, mimicking the behavior of hadrons interacting with a hot, dense medium such as the quark-gluon plasma produced in heavy ion collisions. We present an improved AdS/QCD model for meson and glueball spectra at finite temperature and baryon chemical potential. The spectra match the experimental and lattice data qualitatively well at low temperature, but we also find some subtleties in connecting to the best zero-temperature models. We find a melting temperature for light mesons that is below the current estimates for the deconfinement temperature. Finally, we examine the melting and jet-quenching of heavy quarkonia, which more commonly act as probes of the QGP in heavy ion collisions.
A rotation/magnetism analogy for the quark-gluon plasma
McInnes, Brett
2016-10-01
In peripheral heavy ion collisions, the Quark-Gluon Plasma that may be formed often has a large angular momentum per unit energy. This angular momentum may take the form of (local) rotation. In many physical systems, rotation can have effects analogous to those produced by a magnetic field; thus, there is a risk that the effects of local rotation in the QGP might be mistaken for those of the large genuine magnetic fields which are also known to arise in these systems. Here we use the gauge-gravity duality to investigate this, and we find indeed that, with realistic parameter values, local rotation has effects on the QGP (at high values of the baryonic chemical potential) which are not only of the same kind as those produced by magnetic fields, but which can in fact be substantially larger. Furthermore, the combined effect of rotation and magnetism is to change the shape of the main quark matter phase transition line in an interesting way, reducing the magnitude of its curvature; again, local rotation contributes to this phenomenon at least as strongly as magnetism.
Monte Carlo study of Quark Gluon Plasma using photon jet observables
Xing, Tian
2016-09-01
Relativistic heavy ion collisions create an exotic state of deconfined, nuclear matter called quark gluon plasma (QGP), providing an opportunity to study the strong interaction. In some particularly hard scattered events, a parton with high transverse momentum (pT) interacts with this medium before fragmenting into a spray of particles, called a jet. Jet properties of heavy ion collisions can be modified relative to expectations from pp collisions; this effect is called jet quenching. Measurement of the jet internal structure can provide information about this effect and about the medium itself. On the other hand, studying systems whose jets are recoiled against photons coming from an initial scattering offers a way to calibrate the momentum of the modified jet. Since photons do not carry color charge, they escape the QGP with their initial momentum intact. On this poster, results using the Monte Carlo event generators Pythia and JEWEL will be presented for fragmentation functions and jet suppression from photon-jet events, alongside experimental data from CMS and ATLAS at a center of mass energy of 2.76 TeV. Predictions are also presented for lead-lead collisions at a center of mass energy of 5.02 TeV.
Probing Quark-Gluon-Plasma properties with a Bayesian model-to-data comparison
Cai, Tianji; Bernhard, Jonah; Ke, Weiyao; Bass, Steffen; Duke QCD Group Team
2016-09-01
Experiments at RHIC and LHC study a special state of matter called the Quark Gluon Plasma (QGP), where quarks and gluons roam freely, by colliding relativistic heavy-ions. Given the transitory nature of the QGP, its properties can only be explored by comparing computational models of its formation and evolution to experimental data. The models fall, roughly speaking, under two categories-those solely using relativistic viscous hydrodynamics (pure hydro model) and those that in addition couple to a microscopic Boltzmann transport for the later evolution of the hadronic decay products (hybrid model). Each of these models has multiple parameters that encode the physical properties we want to probe and that need to be calibrated to experimental data, a task which is computationally expensive, but necessary for the knowledge extraction and determination of the models' quality. Our group has developed an analysis technique based on Bayesian Statistics to perform the model calibration and to extract probability distributions for each model parameter. Following the previous work that applies the technique to the hybrid model, we now perform a similar analysis on a pure-hydro model and display the posterior distributions for the same set of model parameters. We also develop a set of criteria to assess the quality of the two models with respect to their ability to describe current experimental data. Funded by Duke University Goldman Sachs Research Fellowship.
What RHIC Experiments and Theory tell us about Properties of Quark-Gluon Plasma ?
Shuryak, E V
2004-01-01
This brief review summarizes the main experimental discoveries made at RHIC and then discusses their implications. The robust collective flow phenomena are well described by ideal hydrodynamics, with the Equation of State (EoS) predicted by lattice simulations. However the transport properties turned out to be unexpected, with rescattering cross section one-to-two orders of magnitude larger than expected from perturbative QCD. These and other theoretical developments indicate that Quark-Gluon Plasma (QGP) produced at RHIC, and probably in a wider temperature region $T_c
Equation of state for hot quark-gluon plasma transitions to hadrons with full QCD potential
Sheikholeslami-Sabzevari, Bijan
2002-05-01
A practical method based on Mayer's cluster expansion to calculate critical values for a quark-gluon plasma (QGP) phase transition to hadrons is represented. It can be applied to a high-temperature QGP for clustering of quarks to mesons and baryons. The potential used is the Cornell potential, i.e., a potential containing both confining and gluon exchange terms. Debye screening effects are included. An equation of state (EOS) for hadron production is found by analytical methods, which is valid near the critical point. The example of the formation of J/ψ and Υ is recalculated. It is shown that in the range of temperatures available by today's accelerators, the latter particles are suppressed. This is further confirmation for heavy quarkonia suppression and, hence, for a signature of a QGP. The EOS presented here also shows that in future colliders there will be no heavy quarkonia production by the mechanism of phase transition. Hence, if there will be heavy quarkonia production, it must be based on some other mechanisms, perhaps on the basis of some recently suggested possibilities.
Heavy-quark transport coefficients in a hot viscous quark-gluon plasma medium
Das, Santosh K.; Chandra, Vinod; Alam, Jan-e.
2014-01-01
Heavy-quark (HQ) transport coefficients have been estimated for a viscous quark-gluon plasma (QGP) medium, utilizing a recently proposed quasi-particle description based on a realistic QGP equation of state (EoS). Interactions entering through the EoS significantly suppress the temperature dependence of the drag coefficient of QGP, compared to those of an ideal relativistic system of quarks and gluons. The inclusion of shear and bulk viscosities through the corrections to the thermal phase space factors of the bath particles alters the magnitude of the drag coefficient; the enhancement is significant at lower temperatures. In the competition between the effects of the EoS and dissipative corrections through phase space factors, the former eventually dictate how the drag coefficient would behave as a function of temperature and how much it quantitatively digresses from the ideal case. The observations suggest a significant impact of both the realistic EoS and the viscosities on the HQs transport at Relativistic Heavy Ion Collider and Large Hadron Collider collision energies.
Spinodal Instabilities of Baryon-Rich Quark-gluon Plasma in the PNJL Model
Li, Feng
2016-01-01
Using the Polyakov-Nambu-Jona-Lasinia (PNJL) model, we study the spinodal instability of a baryon-rich quark-gluon plasma in the linear response theory. We find that the spinodal unstable region in the temperature and density plane shrinks with increasing wave number of the unstable mode and is also reduced if the effect of Polyakov loop is not included. In the small wave number or long wavelength limit, the spinodal boundaries in both cases of with and without the Polyakov loop coincide with those determined from the isothermal spinodal instability in the thermodynamic approach. Also, the vector interactions among quarks is found to suppress unstable modes of all wave numbers. Moreover, the growth rate of unstable modes initially increases with the wave number but is reduced when the wave number becomes large. Including the collisional effect from quark scattering via the linearized Boltzmann equation, we further find that it decreases the growth rate of unstable modes of all wave numbers. Relevance of these...
Perfect Fluidity of the Quark Gluon Plasma Core as Seen through its Dissipative Hadronic Corona
Hirano, T; Hirano, Tetsufumi; Gyulassy, Miklos
2006-01-01
The agreement of hydrodynamic predictions of differential elliptic flow and radial flow patterns with Au+Au data is one of the main lines of evidence suggesting the nearly perfect fluid properties of the strongly coupled Quark Gluon Plasma, sQGP, produced at RHIC. We study the sensitivity of this conclusion to different hydrodynamic assumptions on chemical and thermal freezeout after the sQGP hadronizes. We show that if chemical freezeout occurs at the hadronization time, the differential elliptic flow for pions increase with proper time in the late hadronic phase until thermal freezeout and leads to a discrepancy with the data. In contrast, if both chemical and thermal equilibrium are maintained past the hadronization, then the mean pT per pion increases in a way that accidentally preserves v2(pT) from the sQGP phase in agreement with the data, but at the cost of the agreement with the hadronic yields. In order that all the data on hadronic ratios, radial flow, and differential elliptic flow be reproduced, t...
Resummation of Jet Shapes and Extracting Properties of the Quark-Gluon Plasma
Chien, Yang-Ting
2014-01-01
Understanding the properties of the quark-gluon plasma (QGP) that is produced in ultra-relativistic nucleus-nucleus collisions has been one of the top priorities of the heavy ion program at the LHC. Energetic jets are produced and subsequently quenched in the collisions. Such jet quenching phenomena provide promising tools to probe the medium properties by studying the modification of jets due to the medium interactions. Significant modifications of jet shapes have been measured. In this talk we focus on the calculation of jet shapes in both proton-proton and lead-lead collisions using soft-collinear effective theory (SCET), with Glauber gluon interactions in the medium. Large logarithms in jet shapes are resummed at next-to-leading logarithmic (NLL) accuracy by the renormalization-group evolution between hierarchical jet scales. The medium interactions contribute as power corrections, and we calculate the modification of jet shapes at leading order in opacity with the static QGP model. Preliminary results ar...
Complex suppression patterns distinguish between major energy loss effects in Quark-Gluon Plasma
Djordjevic, Magdalena
2016-12-01
Interactions of high momentum partons with Quark-Gluon Plasma created in relativistic heavy-ion collisions provide an excellent tomography tool for this new form of matter. Recent measurements for charged hadrons and unidentified jets at the LHC show an unexpected flattening of the suppression curves at high momentum, exhibited when either momentum or the collision centrality is changed. Furthermore, a limited data available for B probes indicate a qualitatively different pattern, as nearly the same flattening is exhibited for the curves corresponding to two opposite momentum ranges. We here show that the experimentally measured suppression curves are well reproduced by our theoretical predictions, and that the complex suppression patterns are due to an interplay of collisional, radiative energy loss and the dead-cone effect. Furthermore, for B mesons, we predict that the uniform flattening of the suppression indicated by the limited dataset is in fact valid across the entire span of the momentum ranges, which will be tested by the upcoming experiments. Overall, the study presented here, provides a rare opportunity for pQCD theory to qualitatively distinguish between the major energy loss mechanisms at the same (nonintuitive) dataset.
Electrical Conductivity of Quark-Gluon Plasma in Strong Magnetic Fields
Hattori, Koichi
2016-01-01
We compute the electrical conductivity of quark-gluon plasma in a strong magnetic field $B$ with quantum field theory at finite temperature using the lowest Landau level approximation. We provide the one-loop result arising from 1-to-2 scattering processes whose kinematics are satisfied by the (1+1) dimensional fermion dispersion relation. Due to the chirality conservation, the conductivity diverges in the massless limit, and is sensitive to the value of the current quark mass. As a result, we find that the conductivity along the direction of the magnetic field is quite large compared with the value at $B=0$, mainly because of the small value of the current quark mass. We show that the resummation of the ladder diagrams for the current-current correlator gives rise to only sub-leading contributions beyond the leading-log order, and thus verify our one-loop result at the leading-log accuracy. We also discuss possible implications for the relativistic heavy-ion collisions.
Perturbative and nonperturbative aspects of jet quenching in near-critical quark-gluon plasmas
Xu, Jiechen
In this thesis, we construct two QCD based energy loss models to perform quantitative analysis of jet quenching observables in ultra-relativistic nucleus-nucleus collisions at RHIC and the LHC. We first build up a perturbative QCD based CUJET2.0 jet flavor tomography model that couples the dynamical running coupling DGLV opacity series to bulk data constrained relativistic viscous hydrodynamic backgrounds. It solves the strong heavy quark energy loss puzzle at RHIC and explains the surprising transparency of the quark-gluon plasma (QGP) at the LHC. The observed azimuthal anisotropy of hard leading hadrons requires a path dependent jet-medium coupling in CUJET2.0 that implies physics of nonperturbative origin. To explore the nonperturbative chromo-electric and chromo-magnetic structure of the strongly-coupled QGP through jet probes, we build up a new CUJET3.0 framework that includes in CUJET2.0 both Polyakov loop suppressed semi-QGP chromo-electric charges and emergent chromo-magnetic monopoles in the critical transition regime. CUJET3.0 quantitatively describes the anisotropic hadron suppression at RHIC and the LHC. More significantly, it provides a robust connection between the long wavelength ``perfect fluidity'' of the QGP and the short distance jet transport in the QGP. This framework paves the way for ``measuring'' both perturbative and nonperturbative properties of the QGP, and more importantly for probing color confinement through jet quenching.
Quark production, Bose-Einstein condensates and thermalization of the quark-gluon plasma
Blaizot, Jean-Paul; Yan, Li
2014-01-01
In this paper, we study the thermalization of gluons and N_f flavors of massless quarks and antiquarks in a spatially homogeneous system. First, two coupled transport equations for gluons and quarks (and antiquarks) are derived within the diffusion approximation of the Boltzmann equation, with only 2 2 processes included in the collision term. Then, these transport equations are solved numerically in order to study the thermalization of the quark-gluon plasma. At initial time, we assume that no quarks or antiquarks are present and we choose the gluon distribution in the form f = f_0 theta (1-p/Q_s) with Q_s the saturation momentum and f_0 a constant. The subsequent evolution of systems may, or may not, lead to the formation of a (transient) Bose condensate, depending on the value of f_0. In fact, we observe, depending on the value of f_0, three different patterns: (a) thermalization without gluon Bose-Einstein condensate (BEC) for f_0 1 > f_{0c}, the onset of BEC occurs at a finite time t_c ~ 1/((alpha_s f_0...
Applied string theory, hot and cold. A holographic view on quark-gluon plasma and superfluids
Energy Technology Data Exchange (ETDEWEB)
Samberg, Andreas Wilhelm
2015-12-21
This thesis deals with applications of gauge/gravity duality to strong-coupling phenomena in the quark-gluon plasma and far-from-equilibrium superfluids. In a first part we search for model-independent (universal) behavior in various non-Abelian gauge-theory plasmas at finite temperature and chemical potential. We employ the holographic duals of strongly coupled N=4 supersymmetric Yang-Mills theory and three one-parameter families of non-conformal deformations thereof, two of which solve the equations of motion of a five-dimensional Einstein-Maxwell-scalar action. We study the free energy and associated thermodynamic quantities of heavy quarks and bound quark-anti-quark (Q anti Q) pairs as well as the Q anti Q binding energy and the running coupling. We find qualitative agreement with available lattice QCD data. Moreover, we show that several observables exhibit universal behavior for all values of the chemical potential. In a second part we investigate the real-time dynamics of a bosonic superfluid in two spatial dimensions after initial quenches that take the system to far-from-equilibrium states characterized by many topological vortex defects in association with quantum turbulence. To this end we numerically solve the full equations of motion of the holographically dual Abelian Higgs model on four-dimensional anti-de Sitter space. We observe a universal non-equilibrium late-time regime characterized by power-law behavior in a two-point correlation function and in characteristic length scales, which we interpret as a non-thermal fixed point.
Relating q ̂, η /s , and Δ E in an expanding quark-gluon plasma
Ayala, Alejandro; Dominguez, Isabel; Jalilian-Marian, Jamal; Tejeda-Yeomans, Maria Elena
2016-08-01
We use linear viscous hydrodynamics to describe the energy and momentum deposited by a fast moving parton in a quark gluon plasma. This energy-momentum is in turn used to compute the probability density for the production of soft partons by means of the Cooper-Frye formula. We use this probability density to render manifest a relation between the average transverse momentum given to the fast moving parton from the medium q ̂, the shear viscosity to entropy density ratio η /s , and the energy lost by the fast moving parton Δ E in an expanding medium under similar conditions to those generated in nucleus-nucleus collisions at the CERN Large Hadron Collider. We find that q ̂ increases linearly with Δ E for both trigger and away side partons that have been produced throughout the medium. On the other hand, η /s is more stable with Δ E . We also study how these transport coefficients vary with the geometrical location of the hard scattering that produces the fast moving partons. The behavior of q ̂, with Δ E , is understood as arising from the length of medium the parton traverses from the point where it is produced. However, since η /s is proportional to the ratio of the length of medium traversed by the fast parton and the average number of scatterings it experiences, it has a milder dependence on the energy it loses. This study represents a tool to obtain a direct connection between transport coefficients and the description of in-medium energy loss within a linear viscous hydrodynamical evolution of the bulk.
What RHIC Experiments and Theory tell us about Properties of Quark-Gluon Plasma ?
Shuryak, E. V.
2004-01-01
This brief review summarizes the main experimental discoveries made at RHIC and then discusses their implications. The robust collective flow phenomena are well described by ideal hydrodynamics, with the Equation of State (EoS) predicted by lattice simulations. However the transport properties turned out to be unexpected, with rescattering cross section one-to-two orders of magnitude larger than expected from perturbative QCD. These and other theoretical developments indicate that Quark-Gluon...
Kumar, Yogesh; Singh, S. Somorendro
2016-07-01
We extend the previous study of dilepton production using [S. Somorendro Singh and Y. Kumar, Can. J. Phys. 92 (2014) 31] based on a simple quasiparticle model of quark-gluon plasma (QGP). In this model, finite value of quark mass uses temperature dependent chemical potential the so-called Temperature Dependent Chemical Potential Quark Mass (TDCPQM). We calculate dilepton production in the relevant range of mass region. It is observed that the production rate is marginally enhanced from the earlier work. This is due to the effect of TDCPQM and its effect is highly significant in the production of dilepton.
Niemi, H; Denicol, G S; Huovinen, P; Molnár, E; Rischke, D H
2011-05-27
We investigate the influence of a temperature-dependent shear viscosity over entropy density ratio η/s on the transverse momentum spectra and elliptic flow of hadrons in ultrarelativistic heavy-ion collisions. We find that the elliptic flow in √S(NN)=200 GeV Au+Au collisions at RHIC is dominated by the viscosity in the hadronic phase and in the phase transition region, but largely insensitive to the viscosity of the quark-gluon plasma (QGP). At the highest LHC energy, the elliptic flow becomes sensitive to the QGP viscosity and insensitive to the hadronic viscosity.
Berdnikov, Yu A; Ivanov, A N; Ivanova, V A; Kosmach, V F; Samsonov, V M; Troitskaya, N I; Berdnikov, Ya. A.
2000-01-01
We describe the quark gluon plasma (QGP) as a thermalized quark-gluon system, the thermalized QGP phase of QCD. The hadronization of the thermalized QGP phase is given in a way resembling a simple coalescence model. The input parameters of the approach are the spatial volumes of the hadronization. We introduce three dimensionless parameters C_M, C_B and C_\\bar{B} related to the spatial volumes of the production of low-lying mesons (M), baryons (B) and antibaryons (\\bar{B}). We show that at the temperature T= 175 MeV our predictions for the ratios of multiplicities agree good with the presently available set of hadron ratios measured for various experiments given by NA44, NA49, NA50 and WA97 Collaborations on Pb+Pb collisions at 158 GeV/nucleon, NA35 Collaboration on S+S collisions and NA38 Collaboration on O+U and S+U collisions at 200 GeV/nucleon.
Surdutovich, Y
1998-01-01
We study the dynamics of quantum fluctuations which take place during the earliest stage of high-energy collision processes and the conditions under which the data from e– p deep- inelastic scattering(DIS) may serve as a guide for computing the initial data for heavy- ion collisions at high energies. Our method is essentially based on the space-time picture of these seemingly different phenomena. We analyze the inclusive quantum-mechanical measurements, in both cases, and derive the main results relying on causality. The main result is that the transition from the initial- state composite nuclei to the final-state dense system of quark-gluon fields, i.e. quark-gluon plasma, is possible only as a single quantum transition. We prove that the ultra-violet renormalization of virtual loops does not bring any scale into the problem. The scale appears only in connection with real processes of emission of quark and gluon fields and reveals itself through the collinear cut-off in the evolution equations. Thi...
Bridging soft-hard transport properties of quark-gluon plasmas with CUJET3.0
Energy Technology Data Exchange (ETDEWEB)
Xu, Jiechen [Department of Physics, Columbia University,538 West 120th Street, New York, NY 10027 (United States); Liao, Jinfeng [Physics Department and Center for Exploration of Energy and Matter, Indiana University,2401 North Milo B. Sampson Lane, Bloomington, IN 47408 (United States); RIKEN BNL Research Center, Brookhaven National Laboratory,Building 510A, Upton, NY 11973 (United States); Gyulassy, Miklos [Department of Physics, Columbia University,538 West 120th Street, New York, NY 10027 (United States)
2016-02-25
A new model (CUJET3.0) of jet quenching in nuclear collisions coupled to bulk data constrained (VISH2+1D) viscous hydrodynamic backgrounds is constructed by generalizing the perturbative QCD based (CUJET2.0) model to include two complementary non-perturbative chromodynamical features of the QCD confinement cross-over phase transition near T{sub c}≈160 MeV: (1) the suppression of quark and gluon chromo-electric-charged (cec) degrees of freedom and (2) the emergence of chromo-magnetic-monopole (cmm) degrees of freedom. Such a semi Quark Gluon Monopole Plasma (sQGMP) microscopic scenario is tested by comparing predictions of the leading hadron nuclear modification factors, R{sub AA}{sup h}(p{sub T}>10GeV/c,√s), and their azimuthal elliptic asymmetry v{sub 2}{sup h}(p{sub T}>10GeV/c,√s) with available data on h=π,D,B jet fragments from nuclear collisions at RHIC(√s=0.2 ATeV) and LHC(√s=2.76 ATeV). The cmm degrees of freedom in the sQGMP model near T{sub c} are shown to solve robustly the long standing R{sub AA} vs v{sub 2} puzzle by predicting a maximum of the jet quenching parameter field q̂(E,T)/T{sup 3} near T{sub c}. The robustness of CUJET3.0 model to a number of theoretical uncertainties is critically tested. Moreover the consistency of jet quenching with observed bulk perfect fluidity is demonstrated by extrapolating the sQGMP q̂ down to thermal energy E∼3T scales and showing that the sQGMP shear viscosity to entropy density ratio η/s≈T{sup 3}/q̂ falls close to the unitarity bound, 1/4π, in the range (1−2)T{sub c}. Detailed comparisons of the CUJET2.0 and CUJET3.0 models reveal the fact that remarkably different q̂(T) dependence could be consistent with the same R{sub AA} data and could only be distinguished by anisotropy observables. These findings demonstrate clearly the inadequacy of focusing on the jet path averaged quantity 〈q̂〉 as the only relevant medium property to characterize jet quenching, and point to the crucial roles of
Towards the quark--gluon plasma Equation of State with dynamical strange and charm quarks
Burger, F; Lombardo, M P; Muller-Preussker, M; Trunin, A
2015-01-01
We present an ongoing project aimed at determining the thermodynamic Equation of State (EoS) of quark--gluon matter from lattice QCD with two generations of dynamical quarks. We employ the Wilson twisted mass implementation for the fermionic fields and the improved Iwasaki gauge action. Relying on $T=0$ data obtained by the ETM Collaboration the strange and charm quark masses are fixed at their physical values, while the pion mass takes four values in the range from 470 MeV down to 210 MeV. The temperature is varied within a fixed--lattice scale approach. The values for the pseudocritical temperature are obtained from various observables. For the EoS we show preliminary results for the pure gluonic contribution obtained at the pion mass value 370 MeV, where we can compare with previously obtained results with $N_f=2$ degenerate light flavours.
Jiang, Bing-feng; Hou, De-fu; Li, Jia-rong
2016-10-01
We derive the electric permittivity ɛ and magnetic permeability μM of the quark-gluon plasma (QGP) with the kinetic theory associated with a Bhatnagar-Gross-Krook (BGK) collisional kernel. Based on them, we study the effect of collisions on the refractive index of QGP. Compared to the collisionless case, collisions change the ω -behavior of ɛ and μM dramatically, which is responsible for the fact that the real and imaginary parts of n2 and the Depine-Lakhtakia index nDL are smooth functions of ω . For a small collision rate ν , the Depine-Lakhtakia index nDL is negative in some frequency range. When the collision rate increases, the frequency range for nDLindex nDL is positive for all frequency regions, which indicates a normal refractive index. In contrast to the collisionless case, there exists some frequency range in which nDLnegative refractive index.
Effect of curvature on a statistical model of quark-gluon-plasma fireball in the hadronic medium
Indian Academy of Sciences (India)
S Somorendro Singh; D S Gosain; Yogesh Kumar; Agam K Jha
2010-01-01
The free energy of a quark-gluon plasma fireball in the hadronic medium is calculated in the Ramanathan et al statistical model after incorporating the effect of curvature. The result with the inclusion of curvature is found to produce significant improvements in all the parameters we calculated with respect to the earlier results. The surface tension with this curvature effect is found to be $0.17 T_{c}^{3}$ , which is two times the earlier value of surface tension which is $0.078 T_{c}^{3}$ , and this new result is nearly close to the lattice value $0.24 T_{c}^{3}$. As far as transition is concerned, a thermodynamic variable like entropy shows weakly first-order phase transition and it shows continuity in the behaviour of specific heat.
Production and elliptic flow of dileptons and photons in a matrix model of the quark-gluon plasma.
Gale, Charles; Hidaka, Yoshimasa; Jeon, Sangyong; Lin, Shu; Paquet, Jean-François; Pisarski, Robert D; Satow, Daisuke; Skokov, Vladimir V; Vujanovic, Gojko
2015-02-20
We consider a nonperturbative approach to the thermal production of dileptons and photons at temperatures near the critical temperature in QCD. The suppression of colored excitations at low temperature is modeled by including a small value of the Polyakov loop, in a "semi"-quark-gluon plasma (QGP). Comparing the semi-QGP to the perturbative QGP, we find a mild enhancement of thermal dileptons. In contrast, to leading logarithmic order in weak coupling there are far fewer hard photons from the semi-QGP than the usual QGP. To illustrate the possible effects on photon and dilepton production in heavy-ion collisions, we integrate the rate with a simulation using ideal hydrodynamics. Dileptons uniformly exhibit a small flow, but the strong suppression of photons in the semi-QGP tends to weight the elliptical flow of photons to that generated in the hadronic phase.
Energy Technology Data Exchange (ETDEWEB)
Filinov, V.S.; Fortov, V.E. [Joint Institute for High Temperatures, Russian Academy of Sciences, Izhorskaya 13, bd. 2, 125412 Moscow (Russian Federation); Bonitz, M. [Institute for Theoretical Physics and Astrophysics, Christian Albrechts University Kiel, Leibnizstrasse 15, D-24098 Kiel (Germany); Ivanov, Y.B. [National Research Center ' ' Kurchatov Institute' ' , Kurchatov Sq. 1, 123182 Moscow, Russia, National Research Nuclear University ' ' MEPhI' ' , Kashirskoe sh. 31, 115409 Moscow (Russian Federation); Ilgenfritz, E.M. [Joint Institute for Nuclear Reseach, Joliot-Curie str. 6, Dubna, 141980, Moscow Region (Russian Federation)
2015-02-01
Based on the constituent quasiparticle model of the quark-gluon plasma (QGP), color quantum path-integral Monte-Carlo (PIMC) calculations of the thermodynamic properties of the QGP are performed. We extend our previous zero chemical potential simulations to the QGP at finite baryon chemical potential. The results indicate that color PIMC can be applied not only above the QCD critical temperature T{sub c} but also below T{sub c}. Besides reproducing the lattice equation of state our approach yields also valuable additional insight into the internal structure of the QGP, via the pair distribution functions of the various quasiparticles. In particular, the pair distribution function of gluons reflects the existence of gluon-gluon bound states at low temperatures and μ = 175 MeV, i.e. glueballs, while meson-like bound states are not found. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)
Akamatsu, Yukinao; Nonaka, Chiho; Takamoto, Makoto
2013-01-01
In this article, we present a state-of-the-art algorithm for solving the relativistic viscous hydrodynamic equation with QCD equation of state. The numerical method is based on the second-order Godunov method and has less numerical dissipation, which are crucial in describing of quark-gluon plasma in high energy heavy-ion collisions. We apply the algorithm to several numerical test problems such as sound wave propagation, shock tube and blast wave problems. In the sound wave propagation, the intrinsic {\\em numerical} viscosity is measured and its explicit expression is shown, which is the second-order of spatial resolution both in the presence and absence of {\\em physical} viscosity. The expression of the numerical viscosity can be used to determine the maximum cell size in order to accurately measure the effect of physical viscosity in the numerical simulation.
Cao, Shanshan; Qin, Guang-You; Wang, Xin-Nian
2016-01-01
A Linearized Boltzmann Transport (LBT) model coupled with hydrodynamical background is established to describe the evolution of jet shower partons and medium excitations in high energy heavy-ion collisions. We extend the LBT model to include both elastic and inelastic processes for light and heavy partons in the quark-gluon plasma. A hybrid model of fragmentation and coalescence is developed for the hadronization of heavy quarks. Within this framework, we investigate how heavy flavor observables depend on various ingredients, such as different energy loss and hadronization mechanisms, the momentum and temperature dependences of the transport coefficients, and the radial flow of the expanding fireball. Our model calculations show good descriptions of $D$ meson suppression and elliptic flow observed at the LHC and RHIC. The prediction for the Pb-Pb collisions at $\\sqrt{s_\\mathrm{NN}}$=5.02 TeV is provided.
Quark-Gluon Plasma in a Bag Model with a Soft Surface
Jacobsen, Rafael B.; Marranghello, Guilherme F.; Vasconcellos, César A. Z.; Mesquita, Alexandre
We analyze the implications of quantum hadrodynamics (QHD) and quantum chromodynamics (QCD) to model, respectively, two distinct phases of nuclear matter, a baryon-meson phase and a quark-gluon phase. We develop an equation of state (EoS) in the framework of a quark-meson coupling model for the hadron-meson phase using a new version of the fuzzy bag model with scalar-isoscalar, vector-isoscalar and vector-isovector meson-quark couplings and leptonic degrees of freedom as well as the constrains from chemical equilibrium, baryon number and electric charge conservation. We model the EoS for the QGP phase for asymptotically free massless quarks and gluons using the MIT approach and a temperature and baryon chemical potential dependent bag constant, B(T,μ), which allows an isentropic equilibrium phase transition from a QGP to a hadron gas as determined by thermodynamics. Our predictions yield the EoS and static global properties of neutron stars and protoneutron stars at low and moderate values of temperature. Our results are slightly modified in comparison to predictions based on the standard MIT bag model with a constant bag pressure B.
Equation of State for a Quark Gluon Plasma in the Fuzzy Bag Model
Jacobsen, R. B.; Vasconcellos, C. A. Z.; Bodmann, Bardo E. J.; Dillig, Manfred
2004-12-01
We study two distinct phases of nuclear matter, a baryon-meson phase and a quark-gluon phase (QGP). For the baryon-meson phase we develop an equation of state (EoS) using a quark-meson formulation based on a new version of the fuzzy bag model with scalar-isoscalar, vector-isoscalar and vector-isovector meson-quark couplings and leptonic degrees of freedom as well as the constraints of chemical equilibrium, baryon number and electric charge conservation. For the QGP phase we model an EoS for asymptotically free massless quarks and gluons using the MIT approach and a temperature and baryon chemical potential dependent bag constant, B(T,μ), which allows an isentropic equilibrium phase transition from a QGP to a hadron gas. Our main results indicate the EoS and static global properties of neutron stars and protoneutron stars at low and moderate values of temperature are slightly modified in comparison to the predictions based on the MIT bag model with a constant B.
Dynamical evolution of the chiral magnetic effect: applications to the quark-gluon plasma
Manuel, Cristina
2015-01-01
We study the dynamical evolution of the so-called chiral magnetic effect in an electromagnetic conductor. To this end, we consider the coupled set of corresponding Maxwell and chiral anomaly equations, and we prove that these can be derived from chiral kinetic theory. After integrating the chiral anomaly equation over space in a closed volume, it leads to a quantum conservation law of the total helicity of the system. A change in the magnetic helicity density comes together with a modification of the chiral fermion density. We study in Fourier space the coupled set of anomalous equations and we obtain the dynamical evolution of the magnetic fields, magnetic helicity density, and chiral fermion imbalance. Depending on the initial conditions we observe how the helicity might be transferred from the fermions to the magnetic fields, or vice versa, and find that the rate of this transfer also depends on the scale of wavelengths of the gauge fields in consideration. We then focus our attention on the quark-gluon pl...
Bernhard, Jonah E; Bass, Steffen A; Liu, Jia; Heinz, Ulrich
2016-01-01
We quantitatively estimate properties of the quark-gluon plasma created in ultra-relativistic heavy-ion collisions utilizing Bayesian statistics and a multi-parameter model-to-data comparison. The study is performed using a recently developed parametric initial condition model, TRENTO, which interpolates among a general class of particle production schemes, and a modern hybrid model which couples viscous hydrodynamics to a hadronic cascade. We calibrate the model to multiplicity, transverse momentum, and flow data and report constraints on the parametrized initial conditions and the temperature-dependent transport coefficients of the quark-gluon plasma. We show that initial entropy deposition is consistent with a saturation-based picture, extract a relation between the minimum value and slope of the temperature-dependent specific shear viscosity, and find a clear signal for a nonzero bulk viscosity.
Probing the Quark-Gluon Plasma from bottomonium production at forward rapidity with ALICE at the LHC
Marchisone, Massimiliano
The main goal of ultrarelativistic heavy-ion collisions is the study of the properties of the matter at very high temperatures and energy densities. Quantum chromodynamics (QCD) predicts in these conditions the existence of a new phase of the matter whose components are deconfined in a Quark-Gluon Plasma (QGP). Heavy quarks (charm e bottom) are produced in the first stages of the collisions, before to interact with the medium. Therefore, the measurement of the quarkonia (cc and bb mesons) is of particular interest for the study of the QGP: their dissociation mainly due to the colour screening is sensible to the initial temperature of the medium. Previous measurements at the SPS and RHIC allowed to understand some characteristics of the system produced, but they also opened many questions. With an energy 14 times higher than RHIC, the LHC (Large Hadron Collider) at CERN opened a new era for the study of the QGP properties. ALICE (A Large Ion Collider Experiment) is the LHC experiment fully dedicated to the stu...
Relating $\\hat{q}$, $\\eta/s$ and $\\Delta E$ in an expanding Quark-Gluon Plasma
Ayala, Alejandro; Jalilian-Marian, Jamal; Tejeda-Yeomans, Maria Elena
2016-01-01
We use linear viscous hydrodynamics to describe the energy and momentum deposited by a fast moving parton in a quark gluon plasma. This energy-momentum is in turn used to compute the probability density for the production of soft partons by means of the Cooper-Frye formula. We use this probability density to render manifest a relation between the average transverse momentum given to the fast moving parton from the medium $\\hat{q}$, the entropy density to shear viscosity ratio $\\eta/s$ and the energy lost by the fast moving parton $\\Delta E$ in an expanding medium under similar conditions to those generated in nucleus-nucleus collisions at the LHC. We find that $\\hat{q}$ increases linearly with $\\Delta E$ for both trigger and away side partons that have been produced throughout the medium. On the other hand, $\\eta/s$ is more stable with $\\Delta E$. We also study how these transport coefficients vary with the geometrical location of the hard scattering that produces the fast moving partons. The behavior of $\\ha...
The thermalization of soft modes in non-expanding isotropic quark gluon plasmas
Energy Technology Data Exchange (ETDEWEB)
Blaizot, Jean-Paul, E-mail: jean-paul.blaizot@cea.fr [Institut de Physique Théorique, CNRS/UMR 3681, CEA Saclay, F-91191 Gif-sur-Yvette (France); Liao, Jinfeng [Physics Department and Center for Exploration of Energy and Matter, Indiana University, 2401 N Milo B. Sampson Lane, Bloomington, IN 47408 (United States); RIKEN BNL Research Center, Bldg. 510A, Brookhaven National Laboratory, Upton, NY 11973 (United States); Mehtar-Tani, Yacine [Institute for Nuclear Theory, University of Washington, Seattle, WA 98195-1550 (United States)
2017-05-15
We discuss the role of elastic and inelastic collisions and their interplay in the thermalization of the quark–gluon plasma. We consider a simplified situation of a static plasma, spatially uniform and isotropic in momentum space. We focus on the small momentum region, which equilibrates first, and on a short time scale. We obtain a simple kinetic equation that allows for an analytic description of the most important regimes. The present analysis suggests that the formation of a Bose condensate, expected when only elastic collisions are present, is strongly hindered by the inelastic, radiative, processes.
Bleicher, M; Bleicher, Marcus
2005-01-01
The excitation function of the in-plane directed flow of nucleons is studied within a non-equilibrium transport approach. It is demonstrated that a local minimum in the excitation function of the directed flow develops, which is not related to a transition into a quark-gluon plasma (QGP) phase. It is a consequence of the dynamical softening of the underlying equation of state, due to the onset of resonance matter and particle production. Thus, the interpretation of this minimum as a 'smoking gun' signature for the creation of a QGP is premature.
How big are the smallest drops of quark-gluon plasma?
Chesler, Paul M
2016-01-01
Using holographic duality, we present results for both head-on and off-center collisions of Gaussian shock waves in strongly coupled $\\mathcal N = 4$ supersymmetric Yang-Mills theory. The shock waves superficially resemble Lorentz contracted colliding protons. The collisions results in the formation of a plasma whose evolution is well described by viscous hydrodynamics. The size of the produced droplet is $R \\sim 1/T_{\\rm eff}$ where $T_{\\rm eff}$ is the effective temperature, which is the characteristic microscopic scale in strongly coupled plasma. These results demonstrate the applicability of hydrodynamics to microscopically small systems and bolster the notion that hydrodynamics can be applied to heavy-light ion collisions as well as some proton-proton collisions.
Baryon stopping and quark-gluon plasma production at RHIC and LHC
Energy Technology Data Exchange (ETDEWEB)
Lyakhov, K.
2008-08-15
Strong chromofields developed at early stages of relativistic heavy-ion collisions give rise to the collective deceleration of net baryons from colliding nuclei. We have solved classical equations of motion for baryonic slabs under the action of time-dependent chromofield. We have studied sensitivity of the slab trajectories and their final rapidities to the initial strength and decay pattern of the chromofield as well as to the back reaction of produced plasma. This mechanism can naturally explain significant baryon stopping observed at RHIC, an average rapidity loss left angle {delta}y right angle {approx} 2. Using a Bjorken hydrodynamical model with particle producing source we also study the evolution of partonic plasma produced as the result of chromofield decay. Due to the delayed formation and expansion of plasma its maximum energy density is much lower than the initial energy density of the chromofield. It is shown that the net-baryon and produced parton distributions are strongly correlated in the rapidity space. The shape of net-baryon spectra in midrapidity region found in the BRAHMS experiment cannot be reproduced by only one value of chromofield energy density parameter {epsilon}{sub 0}, even if one takes into account novel mechanisms as fluctuations of color charges generated on the slab surface, and weak interaction of baryon-rich matter with produced plasma. The further step to improve our results is to take into account rapidity dependence of saturation momentum as explained in thesis. Different values of parameter {epsilon}{sub 0} has been tried for different variants of chromofield decay to fit BRAHMS data for net-baryon rapidity distribution. In accordance with our analysis, data for fragmentation region correspond to the lower chromofield energy densities than mid-rapidity region. {chi}{sup 2} analysis favors power-law of chromofield decay with corresponding initial chromofield energy density of order {epsilon}{sub f}=30 GeV/fm{sup 3}. (orig.)
Hydrodynamic transport coefficients for the non-conformal quark-gluon plasma from holography
Finazzo, Stefano I; Marrochio, Hugo; Noronha, Jorge
2014-01-01
In this paper we obtain holographic formulas for the transport coefficients $\\kappa$ and $\\tau_\\pi$ present in the second-order derivative expansion of relativistic hydrodynamics in curved spacetime associated with a non-conformal strongly coupled plasma described holographically by an Einstein+Scalar action in the bulk. We compute these coefficients as functions of the temperature in a bottom-up non-conformal model that is tuned to reproduce lattice QCD thermodynamics at zero baryon chemical potential. We directly compute, besides the speed of sound, 6 other transport coefficients that appear at second-order in the derivative expansion. We also give an estimate for the temperature dependence of 11 other transport coefficients taking into account the simplest contribution from non-conformal effects that appear near the QCD crossover phase transition. Using these results, we construct an Israel-Stewart-like theory in flat spacetime containing 13 of these 17 transport coefficients that should be suitable for ph...
Viewing the Chemical Evolution of the Quark-Gluon Plasma with Charge Balance Functions
Pratt, Scott
2013-01-01
Correlations from charge conservation are affected by when charge/anticharge pairs are created during the course of a relativistic heavy ion collision. For charges created early, balancing charges are typically separated by the order of one unit of spatial rapidity by the end of the collision, whereas those charges produced later in the collision are far more correlated. By analyzing correlations from STAR for different species, I show that one can distinguish the two separate waves of charge creation expected in a high-energy collision, one at early times when the QGP is formed and a second at hadronization. Further, I extract the density of up, down and strange quarks at in the QGP and find agreement at the 20% level with expectations for a chemically thermalized plasma.
Searching for Quark-Gluon Plasma(QGP) Bubble effects at RHIC/LHC
Lindenbaum, S J; Longacre, R S; 10.1140/epjc/s2003-01268-3
2003-01-01
Since the early eighties, we have shared with Leon Van Hove the following view. That if a QGP were produced in high energy heavy ion colliders, that its hadronization products would likely come from small localized in phase space bubbles of plasma. We develop a model based on HIJING, to which we added a ring of adjoining multiple bubbles in the central rapidity region. Our simulations were designed to be tested by the forthcoming RHIC STAR detector data for 65 GeV/n Au colliding with 65 GeV/n Au. We took into account background and resonance effects to allow a direct comparison with the data. Later 100 GeV/n Au colliding with 100 GeV/n Au and LHC data could also test these ideas. We used two charged particle correlation's as a sensitive method to test for bubbles.
The sound generated by a fast parton in the quark-gluon plasma is a crescendo
Neufeld, R. B.; Müller, B.
2009-11-01
The total energy deposited into the medium per unit length by a fast parton traversing a quarkgluon plasma is calculated. We take the medium excitation due to collisions to be given by the well known expression for the collisional drag force. The parton's radiative energy loss contributes to the energy deposition because each radiated gluon acts as an additional source of collisional energy loss in the medium. In our model, this leads to a length dependence on the differential energy loss due to the interactions of radiated gluons with the medium. The final result, which is a sum of the primary and the secondary contributions, is then treated as the coefficient of a local hydrodynamic source term. Results are presented for energy density wave induced by two fast, back-to-back partons created in an initial hard interaction.
The sound generated by a fast parton in the quark-gluon plasma is a crescendo
Energy Technology Data Exchange (ETDEWEB)
Neufeld, R.B.; Mueller, B. [Department of Physics, Duke University, Durham, NC 27708 (United States)
2009-11-01
The total energy deposited into the medium per unit length by a fast parton traversing a quarkgluon plasma is calculated. We take the medium excitation due to collisions to be given by the well known expression for the collisional drag force. The parton's radiative energy loss contributes to the energy deposition because each radiated gluon acts as an additional source of collisional energy loss in the medium. In our model, this leads to a length dependence on the differential energy loss due to the interactions of radiated gluons with the medium. The final result, which is a sum of the primary and the secondary contributions, is then treated as the coefficient of a local hydrodynamic source term. Results are presented for energy density wave induced by two fast, back-to-back partons created in an initial hard interaction.
The errant life of a heavy quark in the quark-gluon plasma
Meyer, Harvey B
2010-01-01
In the high-temperature phase of QCD, the heavy quark momentum diffusion constant determines, via a fluctuation-dissipation relation, how fast a heavy quark kinetically equilibrates. This transport coefficient can be extracted from thermal correlators via a Kubo formula. We present a lattice calculation of the relevant Euclidean correlators in the gluon plasma, based on a recent formulation of the problem in heavy-quark effective field theory (HQET). We find a $\\approx20%$ enhancement of the Euclidean correlator at maximal time separation as the temperature is lowered from $6T_c$ to $2T_c$, pointing to stronger interactions at lower temperatures. At the same time, the correlator becomes flatter from $6T_c$ down to $2T_c$, indicating a relative shift of the spectral weight to lower frequencies. A recent next-to-leading order perturbative calculation of the correlator agrees with the time dependence of the lattice data at the few-percent level. We estimate how much additional contribution from the $\\omega\\lesss...
Lacey, Roy A.; Reynolds, D.; Taranenko, A.; Ajitanand, N. N.; Alexander, J. M.; Liu, Fu-Hu; Gu, Yi; Mwai, A.
2016-10-01
It is shown that the acoustic scaling patterns of anisotropic flow for different event shapes at a fixed collision centrality (shape-engineered events), provide robust constraints for the event-by-event fluctuations in the initial-state density distribution from ultrarelativistic heavy ion collisions. The empirical scaling parameters also provide a dual-path method for extracting the specific shear viscosity {(η /s)}{QGP} of the quark-gluon plasma (QGP) produced in these collisions. A calibration of these scaling parameters via detailed viscous hydrodynamical model calculations, gives {(η /s)}{QGP} estimates for the plasma produced in collisions of Au + Au (\\sqrt{{s}{NN}}=0.2 {TeV}) and Pb + Pb (\\sqrt{{s}{NN}}=2.76 {TeV}). The estimates are insensitive to the initial-state geometry models considered.
Test of Quark-Gluon Plasma of Cylindrical Shape by Two-Pion Interferometry%柱形夸克胶子等离子体的2π干涉学检测
Institute of Scientific and Technical Information of China (English)
陈小凡; 杨学栋; 韩玲
2006-01-01
在2π干涉学中,对不同的π源,2π关联函数可以是不同的.如果在相对论重离子碰撞中出现柱形夸克胶子等离子体,π介子将从柱形夸克胶子等离子体表面发射,此时2π关联函数将出现一种特殊的振荡行为.这种振荡行为可以用来探明夸克胶子等离子体的存在性,同时也是相对论重离子碰撞中出现夸克胶子等离子体的一个信号.%The two-pion correlation functions are different for some pion source distributions in two-pion interferometry. If quark-gluon plasma of cylindrical shape is produced in relativistic heavy ion collisions,the pion mesons will emit from the surface of quark-gluon plasma of cylindrical shape and the corresponding correlation function will have a special oscillation behavior. The oscillation behavior can be used to verify the existence of quark-gluon plasma and is also a signature of the appearance of quark-gluon plasma.
Berges, Jürgen; Reygers, Klaus; Tanji, Naoto; Venugopalan, Raju
2017-05-01
Recent classical-statistical numerical simulations have established the "bottom-up" thermalization scenario of Baier et al. [Phys. Lett. B 502, 51 (2001), 10.1016/S0370-2693(01)00191-5] as the correct weak coupling effective theory for thermalization in ultrarelativistic heavy-ion collisions. We perform a parametric study of photon production in the various stages of this bottom-up framework to ascertain the relative contribution of the off-equilibrium "glasma" relative to that of a thermalized quark-gluon plasma. Taking into account the constraints imposed by the measured charged hadron multiplicities at Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC), we find that glasma contributions are important especially for large values of the saturation scale at both energies. These nonequilibrium effects should therefore be taken into account in studies where weak coupling methods are employed to compute photon yields.
Chen, Jiunn-Wei; Song, Yu-Kun; Wang, Qun
2012-01-01
We calculate the shear (eta) and bulk (zeta) viscosities of a weakly coupled quark gluon plasma at the leading-log order with finite temperature T and quark chemical potential mu. We find that the shear viscosity to entropy density ratio eta/s increases monotonically with mu and eventually scales as (mu/T)^2 at large mu. In contrary, zeta/s is insensitive to mu. Both eta/s and zeta/s are monotonically decreasing functions of the quark flavor number N_f when N_f \\geq 2. This property is also observed in pion gas systems. Our perturbative calculation suggests that QCD becomes the most perfect (i.e. with the smallest eta/s) at mu=0 and N_f = 16 (the maximum N_f with asymptotic freedom). It would be interesting to test whether the currently smallest eta/s computed close to the phase transition with mu=0 and N_f = 0 can be further reduced by increasing N_f.
Mamo, Kiminad A
2016-01-01
We show that a massless quark moving at the speed of light $v=1$, in arbitrary direction, in a strongly coupled $\\mathcal{N}=4$ super Yang-Mills (SYM) vacuum in the presence of strong magnetic field $\\mathcal{B}$, losses its energy at a rate linearly dependent on $\\mathcal{B}$, i.e., $\\frac{dE}{dt}=-\\frac{\\sqrt{\\lambda}}{6\\pi}\\mathcal{B}$. In addition, we show that a heavy quark of mass $M$ moving at near the speed of light $v^2=v_{*}^2=1-\\frac{4\\pi^2 T^2}{\\mathcal{B}}\\simeq1$, in arbitrary direction, in a strongly coupled $\\mathcal{N}=4$ SYM quark-gluon plasma at finite temperature $T$, in the presence of strong magnetic field $\\mathcal{B}\\gg T^2$, losses its energy at a rate linearly dependent on $\\mathcal{B}$, i.e., $\\frac{dE}{dt}=-\\frac{\\sqrt{\\lambda}}{6\\pi}\\mathcal{B}v_{*}^2\\simeq-\\frac{\\sqrt{\\lambda}}{6\\pi}\\mathcal{B}$.
利用不确定性关系计算夸克-胶子等离子体的寿命%To Calculate the Lifetime of Quark-gluon Plasma with Uncertainty Relation
Institute of Scientific and Technical Information of China (English)
王栋; 傅永平
2013-01-01
In this paper, the Uncertainty Relation is used to calculate the lifetime of quark-gluon plasma, this method avoids the complicated theoretical derivation, and the physical meaning and physical process is very clear.%利用不确定性关系可以计算出夸克-胶子等离子体的寿命，这种方法既避免了复杂的理论推导，又明确了物理过程和物理意义。
Li, Shiyong; Yee, Ho-Ung
2016-01-01
We compute the jet quenching parameter $\\hat q$ of QCD plasma in the presence of strong magnetic field in both weakly and strongly coupled regimes. In weakly coupled regime, we compute $\\hat q$ in perturbative QCD at complete leading order (that is, leading log as well as the constant under the log) in QCD coupling constant $\\alpha_s$, assuming the hierarchy of scales $\\alpha_s eB\\ll T^2\\ll eB$. We consider two cases of jet orientations with respect to the magnetic field: 1) the case of jet moving parallel to the magnetic field, 2) the case jet moving perpendicular to the magnetic field. In the former case, we find $\\hat q\\sim \\alpha_s^2 (eB)T\\log(1/\\alpha_s)$, while in the latter we have $\\hat q\\sim \\alpha_s^2 (eB)T\\log(T^2/\\alpha_seB)$. In both cases, this leading order result arises from the scatterings with thermally populated lowest Landau level quarks. In strongly coupled regime described by AdS/CFT correspondence, we find $\\hat q\\sim \\sqrt{\\lambda}(eB)T$ or $\\hat q\\sim\\sqrt{\\lambda}\\sqrt{eB}T^2$ in the...
The Perfect Quark-Gluon Vertex Function
Orginos, K; Brower, Richard C; Chandrasekharan, S; Wiese, U J
1998-01-01
We evaluate a perfect quark-gluon vertex function for QCD in coordinate space and truncate it to a short range. We present preliminary results for the charmonium spectrum using this quasi-perfect action.
Energy Technology Data Exchange (ETDEWEB)
Espagnon, B
2007-10-15
The Alice experiment is one of the four main LHC (Large Hadron Collider) experiments. It is dedicated to the study of a new state of matter: the quark gluon plasma, where quarks and gluons are no longer confined within hadrons. In this document, the physics issues that led to the construction of Alice dimuon spectrometer, are described. Then, the research and development on the dimuon spectrometer is presented. The different absorbers are described and experimental tests used to determine their dimensions are presented. The dimuon trigger built using the RPC (Resistive Plate Chamber) streamer mode is then described along with the associated beam and cosmic tests and results. Finally, the tracking system is described in detail and more particularly all its electronics and the first station. The physics constraints on the expected performances of all these systems are clearly defined. (author)
Institute of Scientific and Technical Information of China (English)
陈勋; 冯笙琴
2016-01-01
首先利用Woods‐Saxon分布，计算相对论重离子碰撞磁场空间分布；并在此基础上考虑夸克胶子等离子体（QGP）的响应，假定QGP为理想导体情况下，研究磁场在QGP环境下的分布特征。%Spatial distributions of magnetic field are calculated in relativistic heavy ion collision based on Woods‐Saxon dis‐tribution .We further study the characteristics of magnetic field distribution while considering Quark gluon plasma (QGP) as an ideal conductor response in a QGP environment .
Energy Technology Data Exchange (ETDEWEB)
Guerin, Fabien [Ecole Doctorale des Sciences Fondamentales, Universite Blaise Pascal, U.F.R de Recherches Scientifiques et Techniques, 34, avenue Carnot - BP 185, 63006 Clermont-Ferrand Cedex (France)
2006-11-15
ALICE (A Large Ion Collider Experiment) is the LHC detector dedicated to the study of ultra-relativistic heavy ion collisions. The main goal of ALICE is the study of a new phase of the nuclear matter predicted by the Quantum Chromodynamics theory (QCD): the Quark-Gluon Plasma (QGP). One of the possible signatures is a suppression of quarkonia yields by color screening in the heavy ion collisions, in which the formation of the QGP is expected. The muon spectrometer will allow measuring of the quarkonia yields (J/{psi}, {upsilon}) in heavy ion collisions via their dimuon decay. A fast trigger, associated to muon spectrometer, has to select events with at least one muon or one dimuon by using a track search algorithm. The study of muon trigger performance will be presented with emphasis on the trigger efficiency and rates in Ar-Ar and Pb-Pb collisions. We will also present the reconstruction of unlike-sign dimuon mass spectrum with the ALICE muon spectrometer. The expected yields of Upsilon states will be extracted from a simulation based on a fit of this spectrum for one month running for Pb-Pb collisions and for different collision centralities. (author)
Energy Technology Data Exchange (ETDEWEB)
Zaraket, H
2000-06-01
This work is devoted to photon and dilepton production in a quark gluon plasma. The theoretical framework in which the study is carried out is Thermal Field Theory, more precisely the hard thermal loop effective theory. Several features of the observables preclude a straightforward application of the effective theory and new tools had to be developed such as the counter term method to avoid double counting. The first part of my study concerns static virtual photon production where I show that important physical contributions are missing in the effective theory at one loop level and hence a two loop calculation is indispensable. Furthermore I give an analytic leading logarithmic estimate of this two loop result showing clearly the insufficiency of the effective theory. The second part of the work focuses on real and quasi real photon production. Again, important contributions arise at two loop level due to collinear divergences. For high mass dilepton the two loop calculation is sufficient. On the other hand, near the light cone photon production rate is non perturbative. Getting closer to the light cone coherent scattering effects (Landau-Pomeranchuk-Migdal effect) arise, which imply the resummation of an infinite series of diagrams. Still nearer the light cone we found a dependence on the non perturbative magnetic mass due to infrared singularities. (author)
Systematics of quark/gluon tagging
Gras, Philippe; Höche, Stefan; Kar, Deepak; Larkoski, Andrew; Lönnblad, Leif; Plätzer, Simon; Siódmok, Andrzej; Skands, Peter; Soyez, Gregory; Thaler, Jesse
2017-07-01
By measuring the substructure of a jet, one can assign it a "quark" or "gluon" tag. In the eikonal (double-logarithmic) limit, quark/gluon discrimination is determined solely by the color factor of the initiating parton ( C F versus C A ). In this paper, we confront the challenges faced when going beyond this leading-order understanding, using both parton-shower generators and first-principles calculations to assess the impact of higher-order perturbative and nonperturbative physics. Working in the idealized context of electron-positron collisions, where one can define a proxy for quark and gluon jets based on the Lorentz structure of the production vertex, we find a fascinating interplay between perturbative shower effects and nonperturbative hadronization effects. Turning to proton-proton collisions, we highlight a core set of measurements that would constrain current uncertainties in quark/gluon tagging and improve the overall modeling of jets at the Large Hadron Collider.
New signals of quark-gluon-hadron mixed phase formation
Energy Technology Data Exchange (ETDEWEB)
Bugaev, K.A.; Sagun, V.V.; Ivanytskyi, A.I.; Zinovjev, G.M. [Bogolyubov Institute for Theoretical Physics, Kiev (Ukraine); Oliinychenko, D.R. [Bogolyubov Institute for Theoretical Physics, Kiev (Ukraine); Goethe University, FIAS, Frankfurt am Main (Germany); Ilgenfritz, E.M. [JINR, Bogoliubov Laboratory of Theoretical Physics, Dubna (Russian Federation); Nikonov, E.G. [JINR, Laboratory for Information Technologies, Dubna (Russian Federation); Taranenko, A.V. [Moscow Engineering Physics Institute, National Research Nuclear University ' ' MEPhI' ' , Moscow (Russian Federation)
2016-08-15
Here we present several remarkable irregularities at chemical freeze-out which are found using an advanced version of the hadron resonance gas model. The most prominent of them are the sharp peak of the trace anomaly existing at chemical freeze-out at the center-of-mass energy 4.9 GeV and two sets of highly correlated quasi-plateaus in the collision energy dependence of the entropy per baryon, total pion number per baryon, and thermal pion number per baryon which we found at the center-of-mass energies 3.8-4.9 GeV and 7.6-10 GeV. The low-energy set of quasi-plateaus was predicted a long time ago. On the basis of the generalized shock-adiabat model we demonstrate that the low-energy correlated quasi-plateaus give evidence for the anomalous thermodynamic properties inside the quark-gluon-hadron mixed phase. It is also shown that the trace anomaly sharp peak at chemical freeze-out corresponds to the trace anomaly peak at the boundary between the mixed phase and quark gluon plasma. We argue that the high-energy correlated quasi-plateaus may correspond to a second phase transition and discuss its possible origin and location. Besides we suggest two new observables which may serve as clear signals of these phase transformations. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Gelis, Francois [Savoie Univ., 73 - Chambery (France)
1998-12-01
The general framework of this work is thermal field theory, and more precisely the perturbative calculation of thermal Green`s functions. In a first part, I consider the problems closely related to the formalism itself. After two introductory chapters devoted to set up the framework and the notations used afterwards, a chapter is dedicated to a clarification of certain aspects of the justification of the Feynman rules of the real time formalism. Then, I consider in the chapter 4 the problem of cutting rules in the real time formalisms. In particular, after solving a controversy on this subject, I generalize these cutting rules to the `retarded-advanced` version of this formalism. Finally, the last problem considered in this part is that of the pion decay into two photons in a thermal bath. I show that the discrepancies found in the literature are due to peculiarities of the analytical properties of the thermal Green`s functions. The second part deals with the calculations of the photons or dilepton (virtual photon) production rate by a quark gluon plasma. The framework of this study is the effective theory based on the resummation of hard thermal loops. The first aspects of this study is related to the production of virtual photons, where we show that important contributions arise at two loops, completing the result already known at one loop. In the case of real photon production, we show that extremely strong collinear singularities make two loop contributions dominant compared to one loop ones. In both cases, the importance of two loop contributions can be interpreted as weaknesses of the hard thermal loop approximation. (author) 366 refs., 109 figs.
Test of Nonstatic Spherical Quark-Gluon Plasma by Two-Pion Interferometry%非静态球形夸克-胶子等离子体的2π干涉学的检测
Institute of Scientific and Technical Information of China (English)
陈小凡
2007-01-01
A model of expanding pion sources in relativistic heavy ion collisions, when only hadronic matter is generated, is proposed. The two-pion correlation function at small relative momentum for such a model is obtained with two-pion interferometry at small relative momentum, and the relation between the real spatial parameter Re and the apparent spatial parameter Ra of the pion sources is given. The relation is different from the one when QGP is created. The difference can be used to test nonstatic, spherical quark-gluon plasma produced in relativistic heavy ion collisions. The relation also showes a scaling behavior.%提出了一种相对论重离子碰撞中强子物质生成时的π膨胀源模型.得到了该模型中的小相对论动量区域的2π关联函数及表观π源参数Ra与实际π源参数Re的关系.这一关系与QGP生成时的关系有所区别.这一区别可以用来检测相对论重离子碰撞中产生的非静态球形夸克-胶子等离子体的存在性.两个关系也显示了一种标度行为.
Chang, Ning-Bo; Qin, Guang-You
2016-08-01
We study the evolution of the full jet shower in quark-gluon plasma by solving a set of coupled differential transport equations for the three-dimensional momentum distributions of quarks and gluons contained in full jets. In our jet evolution equations, we include all partonic splitting processes as well as the collisional energy loss and transverse momentum broadening for both the leading and radiated partons of the full jets. Combining with a realistic (2 +1 )-dimensional viscous hydrodynamic simulation for the spacetime profiles of the hot and dense nuclear medium produced in heavy-ion collisions, we apply our formalism to calculate the nuclear modification of single inclusive full jet spectra, the momentum imbalance of photon-jet and dijet pairs, and the jet shape function (at partonic level) in Pb+Pb collisions at 2.76 A TeV. The roles of various jet-medium interaction mechanisms on the full jet modification are studied. We find that the nuclear modification of jet shape is sensitive to the interplay of different interaction mechanisms as well as the energies of the full jets.
Dilepton Production in a Chemically Equilibrating Quark-Gluon Matter
Institute of Scientific and Technical Information of China (English)
贺泽君; 蒋维洲; 张家驹; 张伟; 刘波
2002-01-01
We have studied dilepton production in a chemically equilibrating quark-gluon matter produced at RHIC energies.We find that the dilepton yield is no longer a monotonically decreasing function of the initial quark chemicalpotential. Therefore, the dilepton suppression may not be useful as a signature for quark-gluon matter formation.
球形夸克-胶子等离子体演化源的π干涉学分析%Pion Interferometry for Spherical Quark-Gluon Plasma Evolution Sources
Institute of Scientific and Technical Information of China (English)
Efaaf M.J.; 张卫宁; Khaliliasr M.; 金恩培; 刘亦铭
2005-01-01
We examine the two-pion interferometry for the expanding sources of spherical quark-gluon plasma evolution. The quarkgluon plasma evolution is described by relativistic hydrodynamics with the equation of state of entropy density. The two-pion HanburyBrown-Twiss (HBT) correlation functions are calculated using quantum probability amplitudes in a path-integral formalism. We find the spatial parameter extracted by the two-pion interferometry is sensitive to the phase-space distribution of the pion-emitting source.The expanding velocity of the source leads to a smaller HBT radius and changes the relationship between the HBT radius and the freeze-ont temperature.%本文对球形演化的夸克-胶子等离子体膨胀源进行了2π干涉学分析.夸克-胶子等离子体的演化由相对论流体力学和熵密度的物态方程描述,而2πHanbury-Brown-Twiss(HBT)关联函数由量子几率振幅的路径积分公式计算.研究结果表明,由2π干涉学得到的源的空间参量敏感地依赖于π介子发射源的相空间分布,源的膨胀速度导致HBT半径变小,并会改变HBT半径与冻结温度之间的关系.
Pion Interferometry for Cylindrical Quark-Gluon Plasma Evolution Sources%柱形夸克-胶子等离子体演化源的π干涉学分析
Institute of Scientific and Technical Information of China (English)
Efaaf M.J.; 张卫宁; Khaliliasr M.; 霍雷; 金恩培; 张景波
2005-01-01
本文对Bjorken柱形夸克-胶子等离子体演化膨胀源进行了2π Hanbury-Brown-Twiss(HBT)干涉学分析.利用量子几率振幅的路径积分公式计算2π HBT关联函数并得到对膨胀和静态源的HBT半径.研究发现,在冻结发射情况下的HBT半径要明显大于没有考虑多重散射吸收情况下的结果,源的膨胀速度导致HBT半径变小.对相变温度宽度为零的Bjorken柱形源,膨胀速度的影响要小于对应的球形源的结果.%We examine the two-pion Hanbury-Brown-Twiss(HBT) interferometry for the expanding sources of quark-gluon plasma evolution with the Bjorken cylinder geometry. The two-pion HBT correlation functions are calculated using quantum probability amplitudes in a path-integral formalism and the HBT radius is extracted both for the expanding source and the static source.We find that the HBT radius for the freeze-out emission case is substantially greater than that for the case without absorption of multiple scattering. The expanding velocity of the source leads to a smaller HBT radius.The effect of expanding velocity for the Bjorken cylinder source with zero width of the transition temperature is smaller than those of the corresponding spherical source.
Isotropization of the quark gluon plasma
Energy Technology Data Exchange (ETDEWEB)
Epelbaum, T.; Gelis, F.
2014-06-15
We report here recent analytical and numerical work on the theoretical treatment of the early stages of heavy ion collisions, that amounts to solving the classical Yang–Mills equations with fluctuating initial conditions. Our numerical simulations suggest a fast isotropization of the pressure tensor of the system. This trend appears already for small values of the coupling constant α{sub s}. In addition, the system exhibits an anomalously small shear viscosity.
Collective Flow signals the Quark Gluon Plasma
Stöcker, H
2005-01-01
A critical discussion of the present status of the CERN experiments on charm dynamics and hadron collective flow is given. We emphasize the importance of the flow excitation function from 1 to 50 A$\\cdot$GeV: here the hydrodynamic model has predicted the collapse of the $v_1$-flow and of the $v_2$-flow at $\\sim 10$ A$\\cdot$GeV; at 40 A$\\cdot$GeV it has been recently observed by the NA49 collaboration. Since hadronic rescattering models predict much larger flow than observed at this energy we interpret this observation as potential evidence for a first order phase transition at high baryon density $\\rho_B$. A detailed discussion of the collective flow as a barometer for the equation of state (EoS) of hot dense matter at RHIC follows. Additionally, detailed transport studies show that the away-side jet suppression can only partially ($<$ 50%) be due to hadronic rescattering. We, finally, propose upgrades and second generation experiments at RHIC which inspect the first order phase transition in the fragmenta...
Charmonium states in quark-gluon plasma
Indian Academy of Sciences (India)
Su Houng Lee; Kenji Morita
2009-01-01
We discuss how the spectral changes of quarkonia at c can reflect the `critical' behaviour of QCD phase transition. Starting from the temperature dependencies of the energy density and pressure from lattice QCD calculation, we extract the temperature dependencies of the scalar and spin-2 gluon condensates near c . We also parametrize these changes into the electric and magnetic condensate near c. While the magnetic condensate hardly changes across c, we find that the electric condensate increases abruptly above c. Similar abrupt change is also seen in the scalar condensate. Using the QCD second-order Stark effect and QCD sum rules, we show that these sudden changes induce equally abrupt changes in the mass and width of /, both of which are larger than 100 MeV at slightly above c.
Working group report: Quark gluon plasma
Indian Academy of Sciences (India)
Pradip Roy; Bedangadas Mohanty; A P Balchandran; A Bhattacharyya; A K Chaudhuri; S Datta; S Digal; F Flueret; S Gupta; P Jaikumar; S H Lee; N Mathur; A Mishra; A P Mishra; H Mishra; B Mohanty; P Roy; P S Somia; A M Srivastava
2009-01-01
The 10th Workshop on High Energy Physics Phenomenology (WHEPP-10) was held at the Institute of Mathematical Sciences, Chennai during January 2–13, 2008. One of our working grops (WG) is QCD and QGP. The discussions of QGP WG include matter at high density, lattice QCD, charmonium states in QGP, viscous hydrodynamics and jet quenching, colour factor in heavy ion collisions and RHIC results on photons, dileptons and heavy quark. There were two plenary talks and several working group talks with intense discussions regarding the future activities that are going to be persued.
Quark-gluon vertex in arbitrary gauge and dimension
Davydychev, A I; Saks, L
2001-01-01
One-loop off-shell contributions to the quark-gluon vertex are calculated, in an arbitrary covariant gauge and in arbitrary space-time dimension, including quark-mass effects. It is shown how one can get results for all on-shell limits of interest directly from the off-shell expressions. In order to demonstrate that the Ward-Slavnov-Taylor identity for the quark-gluon vertex is satisfied, we have also calculated the corresponding one-loop contribution involving the quark-quark-ghost-ghost vertex.
Gaining (Mutual) Information about Quark/Gluon Discrimination
Larkoski, Andrew J; Waalewijn, Wouter J
2014-01-01
Discriminating quark jets from gluon jets is an important but challenging problem in jet substructure. In this paper, we use the concept of mutual information to illuminate the physics of quark/gluon tagging. Ideal quark/gluon separation requires only one bit of truth information, so even if two discriminant variables are largely uncorrelated, they can still share the same "truth overlap". Mutual information can be used to diagnose such situations, and thus determine which discriminant variables are redundant and which can be combined to improve performance. Using both parton showers and analytic resummation, we study a two-parameter family of generalized angularities, which includes familiar infrared and collinear (IRC) safe observables like thrust and broadening, as well as IRC unsafe variants like $p_T^D$ and hadron multiplicity. At leading-logarithmic (LL) order, the bulk of these variables exhibit Casimir scaling, such that their truth overlap is a universal function of the color factor ratio $C_A/C_F$. ...
Quark-gluon vertex: A perturbation theory primer and beyond
Bermudez, R.; Albino, L.; Gutiérrez-Guerrero, L. X.; Tejeda-Yeomans, M. E.; Bashir, A.
2017-02-01
There has been growing evidence that the infrared enhancement of the form factors defining the full quark-gluon vertex plays an important role in realizing a dynamical breakdown of chiral symmetry in quantum chromodynamics, leading to the observed spectrum and properties of hadrons. Both the lattice and the Schwinger-Dyson communities have begun to calculate these form factors in various kinematical regimes of momenta involved. A natural consistency check for these studies is that they should match onto the perturbative predictions in the ultraviolet, where nonperturbative effects mellow down. In this article, we carry out a numerical analysis of the one-loop result for all the form factors of the quark-gluon vertex. Interestingly, even the one-loop results qualitatively encode most of the infrared enhancement features expected of their nonperturbative counter parts. We analyze various kinematical configurations of momenta: symmetric, on shell, and asymptotic. The on-shell limit enables us to compute anomalous chromomagnetic moment of quarks. The asymptotic results have implications for the multiplicative renormalizability of the quark propagator and its connection with the Landau-Khalatnikov-Fradkin transformations, allowing us to analyze and compare various Ansätze proposed so far.
The quark-gluon vertex in Landau gauge bound-state studies
Williams, Richard
2015-05-01
We present a practical method for the solution of the quark-gluon vertex for use in Bethe-Salpeter and Dyson-Schwinger calculations. The efficient decomposition into the necessary covariants is detailed, with the numerical algorithm outlined for both real and complex Euclidean momenta. A truncation of the quark-gluon vertex, that neglects explicit back-coupling to enable the application to bound-state calculations, is given together with results for the quark propagator and quark-gluon vertex for different quark flavours. The relative impact of the various components of the quark-gluon vertex is highlighted with the flavour dependence of the effective quark-gluon interaction obtained, thus providing insight for the construction of phenomenological models within the rainbow ladder. Finally, we solve the corresponding Green's functions for complex Euclidean momenta as required in future bound-state calculations.
The quark-gluon vertex in Landau gauge bound-state studies
Energy Technology Data Exchange (ETDEWEB)
Williams, Richard [Justus-Liebig University of Giessen, Institute of Theoretical Physics, Giessen (Germany)
2015-05-15
We present a practical method for the solution of the quark-gluon vertex for use in Bethe-Salpeter and Dyson-Schwinger calculations. The efficient decomposition into the necessary covariants is detailed, with the numerical algorithm outlined for both real and complex Euclidean momenta. A truncation of the quark-gluon vertex, that neglects explicit back-coupling to enable the application to bound-state calculations, is given together with results for the quark propagator and quark-gluon vertex for different quark flavours. The relative impact of the various components of the quark-gluon vertex is highlighted with the flavour dependence of the effective quark-gluon interaction obtained, thus providing insight for the construction of phenomenological models within the rainbow ladder. Finally, we solve the corresponding Green's functions for complex Euclidean momenta as required in future bound-state calculations. (orig.)
200 A GeV Au + Au collisions serve a nearly perfect quark-gluon liquid.
Song, Huichao; Bass, Steffen A; Heinz, Ulrich; Hirano, Tetsufumi; Shen, Chun
2011-05-13
A new robust method to extract the specific shear viscosity (η/s)(QGP) of a quark-gluon plasma (QGP) at temperatures T(c) QGP with a microscopic transport model for hadronic freeze-out we find for 200 A GeV Au + Au collisions that v2/ε is a universal function of multiplicity density (1/S)(dN(ch)/dy) that depends only on the viscosity but not on the model used for computing the initial fireball eccentricity ε. Comparing with measurements we find 1QGP) < 2.5 where the uncertainty range is dominated by model uncertainties for the values of ε used to normalize the measured v2.
Quark Gluon Condensate,Virtuality and Susceptibility of QCD Vacuum
Institute of Scientific and Technical Information of China (English)
ZHOU Li-Juan; WU Qing; MA Wei-Xing
2008-01-01
We study vacuum of QCD in this work.The structure of non-local quark vacuum condensate,values of various local quark and gluon vacuum condensates,quark-gluon mixed vacuum condensate,quark and gluon virtuality in QCD vacuum state,quark dynamical mass and susceptibility of QCD vacuum state to external field are predicted by use of the solutions of Dyson-Schwinger equations in "rainbow" approximation with a modeling gluon propagator and three different sets of quark-quark interaction parameters.Our theoretical predictions are in good agreement with the correspondent empirical values used widely in literature,and many other theoretical calculations.The quark propagator and self-energy functions are also obtained from the numerical solutions of Dyson-Schwinger equations.This work is centrally important for studying non-perturbative QCD,and has many important applications both in particle and nuclear physics.
Intermediate Mass Dilepton Production in a Chemically Equilibrating Quark-Gluon Matter
Institute of Scientific and Technical Information of China (English)
HE Ze-Jun; ZHOU Wen-Jie; ZHANG Jia-Ju; LIU Bo
2001-01-01
Dilepton production during the chemical equilibration of quark-gluon matter with a finite baryon density has been studied. We find that due to the slowing down of the cooling rate and the high initial temperature of the quark-gluon matter produced at RHIC energies, the quark phase contribution to dileptons with intermediate masses is significantly heightened and is much larger than that calculated by the evolution of the thermodynamic equilibrium system. The latter has shown an enhancement of intermediate mass dileptons from the quark phase. Therefore, such an enhancement of dileptons should be a signature for quark-gluon matter formation.
The quark-gluon vertex in Landau gauge bound-state studies
Williams, Richard
2014-01-01
We present a practical method for the solution of the quark-gluon vertex for use in Bethe--Salpeter and Dyson--Schwinger calculations. The efficient decomposition into the necessary covariants is detailed, with the numerical algorithm outlined for both real and complex Euclidean momenta. A model suitable for bound-state calculations is given together with results for the quark propagator and quark-gluon vertex for different quark flavours. The relative impact of the various components of the quark-gluon vertex is highlighted with the flavour dependence of the effective quark-gluon interaction obtained, thus providing insight for the construction of phenomenological models within Rainbow-Ladder. Finally, we solve the corresponding Green's functions for complex Euclidean momenta as required for practical calculations.
Lattice Landau gauge quark propagator and the quark-gluon vertex
Oliveira, Orlando; Silva, Paulo J; Skullerud, Jon-Ivar; Sternbeck, Andre; Williams, Anthony G
2016-01-01
We report preliminary results of our ongoing lattice computation of the Landau gauge quark propagator and the soft gluon limit of the quark-gluon vertex with 2 flavors of dynamical O(a) improved Wilson fermions.
Energy Technology Data Exchange (ETDEWEB)
Rakotozafindrabe, A
2007-05-15
This work deals with the measurement of the production of J/{psi} in Cu + Cu collisions at 200 GeV per nucleon pair via their decay channel into 2 muons. The experimental data used is that collected during the 2005 campaign at the RHIC. In the first chapter, we present the theoretical context of the study of quark-gluon plasmas (QGP) and its production in relativistic heavy ion collisions. The second chapter deals with the production of J/{psi} in proton-proton collisions and in case of light ion collisions where QGP can not be produced. The experimental setting is presented in the third chapter, particularly the muon spectrometer and the detectors whose purpose is to measure collision centrality. Data analysis concerning the extraction of the signal and the reconstruction of data is described in the fourth chapter. The method that has enabled us to extract the production of the J/{psi} as well as its uncertainties is detailed in the fifth chapter.
A possible evidence of the hadron-quark-gluon mixed phase formation in nuclear collisions
Kizka, V A; Bugaev, K A; Oliinychenko, D R
2015-01-01
The performed systematic meta-analysis of the quality of data description (QDD) of existing event generators of nucleus-nucleus collisions allows us to extract a very important physical information. Our meta-analysis is dealing with the results of 10 event generators which describe data measured in the range of center of mass collision energies from 3.1 GeV to 17.3 GeV. It considers the mean deviation squared per number of experimental points obtained by these event generators, i.e. the QDD, as the results of independent meta-measurements. These generators and their QDDs are divided in two groups. The first group includes the generators which account for the quark-gluon plasma formation during nuclear collisions (QGP models), while the second group includes the generators which do not assume the QGP formation in such collisions (hadron gas models). Comparing the QDD of more than a hundred of different data sets of strange hadrons by two groups of models, we found two regions of the equal quality description o...
Quark-gluon tagging with shower deconstruction: Unearthing dark matter and Higgs couplings
Ferreira de Lima, Danilo; Petrov, Petar; Soper, Davison; Spannowsky, Michael
2017-02-01
The separation of quark and gluon initiated jets can be an important way to improve the sensitivity in searches for new physics or in measurements of Higgs boson properties. We present a simplified version of the shower deconstruction approach as a novel observable for quark-gluon tagging. Assuming topoclusterlike objects as input, we compare our observable with energy correlation functions and find a favorable performance for a large variety of jet definitions. We address the issue of infrared sensitivity of quark-gluon discrimination. When this approach is applied to dark matter searches in monojet final states, limitations from small signal-to-background ratios can be overcome. We also show that quark-gluon tagging is an alternative way of separating weak boson from gluon-fusion production in the process p +p →H +jet+jet+X .
Thermo-magnetic behavior of the of the quark-gluon vertex
Ayala, Alejandro; Loewe, M; Tejeda-Yeomans, Maria Elena; Zamora, R
2015-01-01
The thermo-magnetic corrections to the quark-gluon vertex in the presence of a weak magnetic field are calculated in the frame of the Hard Thermal Loop approximation. The vertex satisfies a QED-like Ward identity with the quark self-energy calculated within the same approximation. It turns out that only the longitudinal vertex components get modified. The calculation provides a first principles result for the quark anomalous magnetic moment at high temperature in a weak magnetic field. The effective thermo-magnetic quark-gluon coupling shows a decreasing behavior as function of the field strength. This result supports the observation that the behavior of the effective quark-gluon coupling in the presence of a magnetic field is an important ingredient in order to understand the inverse magnetic catalysis phenomenon recently observed in the lattice QCD simulations.
SPECTRAL PROPERTIES OF QUARKS IN THE QUARK-GLUON PLASMA.
Energy Technology Data Exchange (ETDEWEB)
KARSCH,F.; KITAZAWA, M.
2007-07-30
We analyze the spectral properties of the quark propagator above the critical temperature for the deconfinement phase transition in quenched lattice QCD using clover improved Wilson fermions. The bare quark mass dependence of the quark spectral function is analyzed by varying the hopping parameter {kappa} in Landau gauge. We assume a two-pole structure for the quark spectral function, which is numerically found to work quite well for any value of {kappa}. It is shown that in the chiral limit the quark spectral function has two collective modes that correspond to the normal and plasmino excitations, while it is dominated by a single-pole structure when the bare quark mass becomes large.
Entropy production for an interacting quark-gluon plasma
Mattiello, Stefano
2011-01-01
We investigate the entropy production within dissipative hydrodynamics in the Israel-Stewart (IS) and Navier-Stokes theory (NS) for relativistic heavy ion physics applications. In particular we focus on the initial condition in a 0+1D Bjorken scenario, appropriate for the early longitudinal expansion stage of the collision. Going beyond the standard simplification of a massless ideal gas we consider a realistic equation of state consistently derived within a virial expansion. The EoS used is well in line with recent three-flavor QCD lattice data for the pressure, speed of sound, and interaction measure at nonzero temperature and vanishing chemical potential ($\\mu_{\\rm q} = 0$). The shear viscosity has been consistently calculated within this formalism using a kinetic approach in the ultra-relativistic regime with an explicit and systematic evaluation of the transport cross section as function of temperature. We investigate the influence of the viscosity and the initial condition, i.e. formation time, initial ...
Viscous quark-gluon plasma in the early universe
Energy Technology Data Exchange (ETDEWEB)
Tawfik, A.; Wahba, M. [Egyptian Center for Theoretical Physics (ECTP), MTI University, Al-Mukkatam, Cairo 11212 (Egypt); Mansour, H. [Department of Physics, Cairo University, Giza 12613 (Egypt); Harko, T. [Department of Physics and Center for Theoretical and Computational Physics, The University of Hong Kong, Pok Fu Lam Road (China)
2011-03-15
In the present work a study is given for the evolution of a flat, isotropic and homogeneous Universe, which is filled with a causal bulk viscous cosmological fluid. We describe the viscous properties by an ultra-relativistic equation of state, and bulk viscosity coefficient obtained from recent lattice QCD calculations. The basic equation for the Hubble parameter is derived by using the energy equation obtained from the assumption of the covariant conservation of the energy-momentum tensor of the matter in the Universe. By assuming a power law dependence of the bulk viscosity coefficient, temperature and relaxation time on the energy density, we derive the evolution equation for the Hubble function. By using the equations of state from recent lattice QCD simulations and heavy-ion collisions we obtain an approximate solution of the field equations. In this treatment for the viscous cosmology, no evidence for singularity is observed. For example, both the Hubble parameter and the scale factor are finite at t=0, where t is the comoving time. Furthermore, their time evolution essentially differs from the one associated with non-viscous and ideal gas. Also it is noticed that the thermodynamic quantities, like temperature, energy density and bulk pressure remain finite. Particular solutions are also considered in order to prove that the free parameter in this model does qualitatively influence the final results. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Viscous Quark-Gluon Plasma in the Early Universe
Tawfik, A; Mansour, H; Harko, T
2010-01-01
We consider the evolution of a flat, isotropic and homogeneous Friedmann-Robertson-Walker Universe, filled with a causal bulk viscous cosmological fluid, that can be characterized by an ultra-relativistic equation of state and bulk viscosity coefficient obtained from recent lattice QCD calculations. The basic equation for the Hubble parameter is derived under the assumption that the total energy in the Universe is conserved. By assuming a power law dependence of bulk viscosity coefficient, temperature and relaxation time on energy density, an approximate solution of the field equations has been obtained, in which we utilized equations of state from recent lattice QCD simulations QCD and heavy-ion collisions to derive an evolution equation. In this treatment for the viscous cosmology, we found no evidence for singularity. For example, both Hubble parameter and scale factor are finite at $t=0$, $t$ is the comoving time. Furthermore, their time evolution essentially differs from the one associated with non-visco...
Physics of hot hadronic matter and quark-gluon plasma
Energy Technology Data Exchange (ETDEWEB)
Shuryak, E.V.
1990-07-01
This Introductory talk contains a brief review of the current status of theoretical and experimental activities related to physics of superdense matter. In particular, we discuss latest lattice results on the phase transition, recent progress in chiral symmetry physics based on the theory of interacting instantons, new in the theory of QGP and of hot hadronic matter, mean p{sub t} and collective flow, the shape of p{sub t} distribution, strangeness production, J/{psi} suppression and {phi} enhancement, two puzzles connected with soft pion and soft photon enhancements, and some other ultrasoft'' phenomena. 56 refs., 6 figs.
Spectral functions in the quark-gluon plasma
Energy Technology Data Exchange (ETDEWEB)
Asakawa, Masayuki [Kyoto Univ., Kyoto (Japan)
2002-09-01
Using the maximum entropy method, spectral functions of the vector mesons are extracted from lattice Monte Carlo data of the zero-temperature imaginary time Green's functions. The resonance and continuum structures as well as the ground state peaks are successfully obtained. In addition, we present a preliminary result for finite temperature spectral functions in the vector channel above the confinement-deconfinement phase transition temperature. (author)
The Strongly Interacting Quark Gluon Plasma at RHIC and LHC
Directory of Open Access Journals (Sweden)
Tserruya Itzhak
2014-04-01
Full Text Available The study of heavy-ion collisions has currently unprecedented opportunities with two first class facilities, the Relativistic Heavy Ion Collider (RHIC at BNL and the Large Hadron Collider (LHC at CERN, and five large experiments ALICE, ATLAS, CMS, PHENIX and STAR producing a wealth of high quality data. Selected results recently obtained are presented on the study of flow, energy loss and direct photons.
On diquark clustering in quark-gluon plasma
Indian Academy of Sciences (India)
A K Sisodiya; V S Bhasin; R S Kaushal
2006-02-01
The possibility that pairs of quarks will form diquark clusters in the regime above deconfinement transition for hadron matter at finite density is revisited. Here we present the results on the diquark-diquark (dq-dq) interaction in the framework of constituent quark model taking account of spin, isospin and color degrees of freedom in the spirit of generalized Pauli principle. By constructing the appropriate spin and color states of the dq-dq clusters we compute the expectation values of the interaction Hamiltonian involving pairwise quark-quark interaction. We find that the effective interaction between two diquark clusters is quite sensitive to different configurations characterized by color and spin states, obtained after the coupling of two diquark states. The value of the coupling parameter for a particular color-spin state, i.e., $\\{\\bar{3}, 1\\}$ is compared to the one obtained earlier by Donoghue and Sateesh, Phys. Rev. D38, 360 (1988) based on the effective 4-theory. This new value of derived for different color-spin dq-dq states, may lead to several important implications in the studies of diquark star and diquark gas.
Workshop on Quark-Gluon Plasma and Relativistic Heavy Ions
Lombardo, Maria Paola; Nardi, Marzia; GISELDA 2002; QGP 2002
2002-01-01
This book offers the unique possibility of tackling the problem of hadronic deconfinement from different perspectives. After general introductions to the physical issues, from both the theoretical and the experimental point of view, the book presents the most recent expertise on field theory approaches to the QCD phase diagram, many-body techniques and applications, the dynamics of phase transitions, and phenomenological analysis of relativistic heavy ion collisions. One of the major goals of this book is to promote interchange among those fields of research, which have traditionally been cult
Nonperturbative equation of state of quark gluon plasma: Applications
Komarov, E. V.; Simonov, Yu. A.
2008-05-01
The vacuum-driven nonperturbative factors Li for quark and gluon Green's functions are shown to define the nonperturbative dynamics of QGP in the leading approximation. EoS obtained recently in the framework of this approach is compared in detail with known lattice data for μ = 0 including P/ T4, ɛ/ T4, {ɛ-3P}/{T4}. The basic role in the dynamics at T ≲ 3 Tc is played by the factors Li which are approximately equal to the modulus of Polyakov line for quark Lfund and gluon Ladj. The properties of Li are derived from field correlators and compared to lattice data, in particular the Casimir scaling property Ladj=(Lfund) follows in the Gaussian approximation valid for small vacuum correlation lengths. Resulting curves for P/ T4, ɛ/ T4, {ɛ-3P}/{T4} are in a reasonable agreement with lattice data, the remaining difference points out to an effective attraction among QGP constituents.
Nonperturbative equation of state of quark-gluon plasma. Applications
Komarov, E V
2007-01-01
The vacuum-driven nonperturbative factors $L_i$ for quark and gluon Green's functions are shown to define the nonperturbative dynamics of QGP in the leading approximation. EoS obtained recently in the framework of this approach is compared in detail with known lattice data for $\\mu=0$ including $P/T^4$, $\\epsilon/T^4$, $\\frac{\\epsilon-3P}{T^4}$. The basic role in the dynamics at $T\\la 3T_c$ is played by the factors $L_i$ which are approximately equal to the modulus of Polyakov line for quark $L_{fund}$ and gluon $L_{adj}$. The properties of $L_i$ are derived from field correlators and compared to lattice data, in particular the Casimir scaling property $L_{adj} =(L_{fund})^{\\frac{C_2(adj)}{C_2(fund)}}$ follows in the Gaussian approximation valid for small vacuum correlation lengths. Resulting curves for $P/T^4$, $\\epsilon/T^4$, $\\frac{\\epsilon-3P}{T^4}$ are in a reasonable agreement with lattice data, the remaining difference points out to an effective attraction among QGP constituents.
Thermal rho`s in the quark-gluon plasma
Energy Technology Data Exchange (ETDEWEB)
Pisarski, R.D.
1995-03-01
I discuss different models which predict changes in the mass of the thermal {rho} field. I emphasize that while the predictions are strongly model dependent, nevertheless substantial shifts in the thermal {rho} mass are expected to occur at the point of phase transition. As long as the thermal {rho} peak does not become too broad, this should provide a striking signature of the existence of a phase transition.
Properties of the Quark Gluon Plasma: A lattice perspective
Karsch, Frithjof
2007-01-01
We discuss results from lattice calculations for a few observables that are sensitive to different length scales in the high temperature phase of QCD and can give insight into its non-perturbative structure. We compare lattice results with perturbative calculations at high temperature obtained for vanishing and non-vanishing quark chemical potential.
Spectral Properties of Quarks in the Quark-Gluon Plasma
Karsch, F
2007-01-01
We analyze the spectral properties of the quark propagator above the critical temperature for the deconfinement phase transition in quenched lattice QCD using clover improved Wilson fermions. The bare quark mass dependence of the quark spectral function is analyzed by varying the hopping parameter \\kappa in Landau gauge. We assume a two-pole structure for the quark spectral function, which is numerically found to work quite well for any value of \\kappa. It is shown that in the chiral limit the quark spectral function has two collective modes that correspond to the normal and plasmino excitations, while it is dominated by a single-pole structure when the bare quark mass becomes large.
Holographic Duals of Quark Gluon Plasmas with Unquenched Flavors
Institute of Scientific and Technical Information of China (English)
Francesco Bigazzi; Aldo Cotrone; Javier Mas; Daniel Mayerson; Javier Tarrio
2012-01-01
We review the construction of gravitational solutions holographically dual to N = 1 quiver gauge theories with dynamical flavor multiplets. We focus on the D3-D7 construction and consider the finite temperature, finite quark chemical potential case where there is a charged black hole in the dual solution. Discussed physical outputs of the model include its thermodynamics （with susceptibilities） and general hydrodynamic properties.
2015-01-01
Follow Italian @ALICEexperiment physicist Chiara Zampolli from INFN Bologna, Italy, as she shares her thoughts about the new physics frontiers opening up when the LHC begins collisions at the higher energy of #13TeV. Each week a new video will be uploaded to https://www.youtube.com/playlist?list... allowing you to follow physicists from @ATLASexperiment @ALICEexperiment @CMSexperiment or @LHCbExperiment as the search the new frontiers in physics. Read more about these new frontiers in physics: http://cern.ch/go/x8VH
Thermal $\\varrho$s in the quark-gluon plasma
Pisarski, R D
1995-01-01
I discuss different models which predict changes in the mass of the thermal \\rho field. I emphasize that while the predictions are strongly model dependent, nevertheless substantial shifts in the thermal \\rho mass are expected to occur at the point of phase transition. As long as the thermal \\rho peak does not become too broad, this should provide a striking signature of the existence of a phase transition. (Based upon a talk presented at Quark Matter '95, Monterey, CA, Jan., 1995.)
Thermal charm and charmonium production in quark gluon plasma
Directory of Open Access Journals (Sweden)
Kai Zhou
2016-07-01
Full Text Available We study the effect of thermal charm production on charmonium regeneration in high energy nuclear collisions. By solving the kinetic equations for charm quark and charmonium distributions in Pb+Pb collisions, we calculate the global and differential nuclear modification factors RAA(Npart and RAA(pt for J/ψ s. Due to the thermal charm production in hot medium, the charmonium production source changes from the initially created charm quarks at SPS, RHIC and LHC to the thermally produced charm quarks at Future Circular Collider (FCC, and the J/ψ suppression (RAA1 at FCC at low transverse momentum.
Building a non-perturbative quark-gluon vertex from a perturbative one
Bermudez, Rocio
2016-10-01
The quark-gluon vertex describes the electromagnetic and the strong interaction among these particles. The description of this interaction at high precision in both regimes, perturbative and non-perturbative, continues being a matter of interest in the context of QCD and Hadron Physics. There exist very helpful models in the literature that explain perturbative aspects of the theory but they fail describing non-perturbative phenomena, as confinement and dynamic chiral symmetry breaking. In this work we study the structure of the quark-gluon vertex in a non-perturbative regime examining QCD, checking results with QED, and working in the Schwinger-Dyson formalism.
Branching structure of QCD jets: new jet observables for quark-gluon discrimination
Davighi, Joseph (CERN)
2014-01-01
I have explored the fractal nature of hadronic jets and the potential use of fractal dimension in jet substructure physics. A more sophisticated set of parameters, named Branching Logarithmic Fit (BLF) parameters, has subsequently been developed to describe the fractal and corrections-to-fractal behavior due to QCD running in the perturbative regime. Theoretical motivation is given for these parameters, which have then been applied to the problem of quark/gluon discrimination. The BLF parameters are individually discriminating and only weakly correlated to variables currently used in quark/gluon discrimination. Consequently, their inclusion should improve discrimination, and evidence is presented for this at the generator level
Consequences Of Fully Dressing Quark-Gluon Vertex Function With Two-Point Gluon Lines
Matevosyan, Hrayr H; Tandy, Peter C
2007-01-01
We extend recent studies of the effects of quark-gluon vertex dressing upon the solutions of the Dyson-Schwinger equation for the quark propagator. A momentum delta function is used to represent the dominant infrared strength of the effective gluon propagator so that the resulting integral equations become algebraic. The quark-gluon vertex is constructed from the complete set of diagrams involving only 2-point gluon lines. The additional diagrams, including those with crossed gluon lines, are shown to make an important contribution to the DSE solutions for the quark propagator, because of their large color factors and the rapid growth in their number.
Branching structure of QCD jets: new jet observables for Quark/Gluon discrimination
Davighi, Joseph
2014-01-01
I have explored the fractal nature of hadronic jets and the potential use of fractal dimension in jet substructure physics. A more sophisticated set of parameters, named Branching Logarithmic Fit (BLF) parameters, has subsequently been developed to describe the fractal and corrections-to-fractal behaviour due to QCD running in the perturbative regime. Theoretical motivation is given for these parameters, which have then been applied to the problem of quark/gluon discrimination. The BLF parameters are individually discriminating and only weakly correlated to variables currently used in quark/gluon discrimination. Consequently, their inclusion should improve discrimination, and evidence is presented for this at the generator level.
Institute of Scientific and Technical Information of China (English)
管娜娜
2016-01-01
Dileptons have large mean free paths due to their small cross sections for electromagnetic interaction in plasma. Therefore they are considered to be an important probe for the formation and evolution of the quark matter. In this work, we calculate the dilepton production of quark-gluon plasma (QGP) produced in Au197+Au197 central collisions at relativistic heavy ion collider (RHIC) energy based on the evolution model of a chemically equilibrating viscous QGP. The evolution of the QGP system is described by a set of coupled relaxation equations containing the master equations of partons, the equation of baryon number conservation and equation of energy-momentum conservation. Solving the set of evolution equations, one can obtain the evolution of temperature T , quark chemical potential µq, fugacitiesλq for quarks andλg for gluons. To discuss the shear viscosity of QGP, the contributions of the elastic scattering of quarks q¯q−→q¯q and gluons gg→gg, as well as the inelastic scattering process of gluons gg↔ggg are included. Based on the evolution model including the viscosity, we perform a complete calculation of the dilepton production, including the processes of quark-antiquark annihilation q¯q→l¯l, next-order annihilation q¯q→gl¯l, Compton-like scattering qg → ql¯l, ¯qg → ¯ql¯l, multiple scattering of quarks, as well as gluon fusion gg → c¯c, annihilation q¯q→c¯c. It is found that the spectra from the quark-antiquark annihilations q¯q→l¯l and q¯q→gl¯l are dominated. The contributions from multiple scattering cannot be neglected. We also find that the dilepton yields remarkably decrease with considering an additional gluon inelastic process in the calculation compared with the results with considering only elastic scatterings of quarks and gluons. This indicates that the evolution of QGP system is accelerated and the evolution time is shortened by the inelastic scatterings of gluons.%双轻子是研究夸克物质的形
Renormalizability of a quark-gluon model with soft BRST breaking in the infrared region
Baulieu, L; Gomez, A J; Lemes, V E R; Sobreiro, R F; Sorella, S P
2010-01-01
We prove the renormalizability of a quark-gluon model with a soft breaking of the BRST symmetry, which accounts for the modification of the large distance behavior of the quark and gluon correlation functions. The proof is valid to all orders of perturbation theory, by making use of softly broken Ward identities.
Intermediate mass dilepton production in a chemically equilibrating quark-gluon matter
Institute of Scientific and Technical Information of China (English)
无
2003-01-01
We find that in a chemically equilibrating baryon-rich quark-gluon matter, due to the slow cooling rate, high initial temperature, large gluon density as well as large fusion cross section ofin the intermediate mass region, the gluon fusion provides a dominant contribution to dileptons with intermediate masses, resulting in the significant enhancement of intermediate mass dileptons.
Energy Technology Data Exchange (ETDEWEB)
Pillot, Ph
2005-05-15
The study of heavy quark production such as J/{psi} (cc-bar resonance) and {upsilon} (bb-bar resonance) in heavy ion collisions at high incident energies has been proposed as a tool to investigate the formation of a Quark Gluon Plasma. Experimentally, these resonances can be detected through their decay channel into a muon pair, using a muon spectrometer. The optimal resolution of a muon spectrometer cannot be reached unless the position of the different tracking detectors are accurately known. In the first part of the work reported in this thesis are presented the design and performances of the Geometry Monitoring System of the ALICE experiment's muon spectrometer at LHC. This system, which is composed of several hundreds of RASNIK derived optical devices, allows to measure displacements and deformations of the chambers with a precision better than a hundred of microns. Thanks to its muon spectrometer associated with a vertex telescope, the NA60 experiment studies the dimuon production in nucleus-nucleus collisions at CERN SPS. The second part of the work reported in this thesis is related to the analysis of the data collected in indium-indium collisions at 158 GeV/c/nucleon. More specifically, the J/{psi} production together with its transverse momentum and transverse mass distributions are studied as a function of the centrality of the collision. The different results arising from our analysis are then compared to those obtained previously by NA38 and NA50, allowing a better understanding of the ultrarelativistic heavy ion collisions. (author)
Propagation of cosmic rays through the atmosphere in the quark-gluon strings model
Erlykin, A. D.; Krutikova, N. P.; Shabelski, Y. M.
1985-01-01
The quark-gluon strings model succeeds in the description of multiple hadron production in the central rapidity region of nucleon-nucleon interctions. This model was developed for hadron-nucleus interactions and used for calculation of the cosmic ray propagation through the atmosphere. It is shown that at energies 10 to the 11th power to the 12th power eV, this model gives a satisfactory description of experimental data. But with the increase of the energy up to approximately 10 to the 14th power eV, results of calculations and of experiments begin to differ and this difference rises with the energy. It may indicate that the scaling violation in the fragmentation region of inclusive spectra for hadron-nucleus interactions is stronger than in the quark-gluon strings model.
QCD sum rules for quark-gluon three-body components in the B meson
Nishikawa, Tetsuo
2011-01-01
We discuss the QCD sum rule calculation of the heavy-quark effective theory parameters, $\\lambda_E$ and $\\lambda_H$, which correspond to matrix elements representing quark-gluon three-body components in the $B$-meson wavefunction. We derive the sum rules for $\\lambda_{E,H}$ calculating the new higher-order QCD corrections, i.e., the order $\\alpha_s$ radiative corrections to the Wilson coefficients associated with the dimension-5 quark-gluon mixed condensates, and the power corrections due to the dimension-6 vacuum condensates. We find that the new radiative corrections significantly improve the stability of the corresponding Borel sum rules and lead to the reduction of the values of $\\lambda_{E,H}$. We also discuss the renormalization-group improvement for the sum rules and present update on the values of $\\lambda_{E,H}$.
Production of phi-mesons on nuclear targets in the Quark-Gluon String model
Arakelyan, G H; Shabelski, Yu M
2016-01-01
We consider the experimental data on phi-meson production on nuclear targets, and we find that they present unusually small shadow corrections for the inclusive density in the midrapidity region. We also give a quantitatively consistent description of both the initial energy dependence and the A-dependence of the produced phi-mesons, obtained in the frame of the Quark-Gluon String Model.
Influence of the nonperturbative quark-gluon vertex on the meson and baryon spectrum
Energy Technology Data Exchange (ETDEWEB)
Williams, Richard; Sanchis-Alepuz, Hèlios [Institut für Theoretische Physik, Justus-Liebig–Universität Giessen, 35392 Giessen (Germany)
2016-01-22
We present a calculation of the Hadron spectrum in the Dyson-Schwinger/Bethe-Salpeter approach to continuum QCD. A sophisticated truncation featuring all covariant structures of the quark-gluon vertex, with its inherent flavour dependence, is employed in a framework that preserves the dynamics of chiral symmetry breaking. The study is suggestive as to the relevance of additional resonant and non-resonant two- and three-body contributions.
Thermal Charmed Quark Contribution to Dileptons in Chemically Equilibrating Quark-Gluon Matter
Institute of Scientific and Technical Information of China (English)
贺泽君; 龙家丽; 卢朝辉; 马余刚; 刘波
2003-01-01
We find that in a chemically equilibrating baryon-rich quark-gluon matter, due to the slow cooling rate, high initial temperature, large gluon density as well as large fusion cross section of gg → c(c) in the intermediate mass region, the gluon fusion gg → c(c) provides a dominant contributionto dileptons with intermediate masses, resulting in the significant enhancement of intermediate mass dileptons.
Hadronic and Quark-Gluon Excitations of Dense and Hot Matter
Renk, T; Weise, W
2002-01-01
We summarize recent developments in our understanding of low-mass quark-antiquark excitations in hadronic matter under various different conditions. This includes the thermodynamics of the chiral condensate, pions as Goldstone bosons in normal nuclear matter, and excursions into extreme territory of the QCD phase diagram: lepton pair production from a fireball expanding through the transition boundary between the quark-gluon and hadron pha ses of QCD.
New approach to initializing hydrodynamic fields and mini-jet propagation in quark-gluon fluids
Okai, Michito; Kawaguchi, Koji; Tachibana, Yasuki; Hirano, Tetsufumi
2017-05-01
We propose a new approach to initialize the hydrodynamic fields, such as energy density distributions and four-flow velocity fields in hydrodynamic modeling of high-energy nuclear collisions at the collider energies. Instead of matching the energy-momentum tensor or putting the initial conditions of quark-gluon fluids at a fixed initial time, we utilize a framework of relativistic hydrodynamic equations with source terms to describe the initial stage. Putting the energy and momentum loss rate of the initial partons into the source terms, we obtain hydrodynamic initial conditions dynamically. The resultant initial profile of the quark-gluon fluid looks highly bumpy as seen in the conventional event-by-event initial conditions. In addition, initial random flow velocity fields also are generated as a consequence of momentum deposition from the initial partons. We regard the partons that survive after the dynamical initialization process as the mini-jets and find sizable effects of both mini-jet propagation in the quark-gluon fluids and initial random transverse flow on the final momentum spectra and anisotropic flow observables. We perform event-by-event (3+1)-dimensional ideal hydrodynamic simulations with this new framework that enables us to describe the hydrodynamic bulk collectivity, parton energy loss, and interplay among them in a unified manner.
Energy Technology Data Exchange (ETDEWEB)
Scharenberg, R.; Hirsch, A.; Tincknell, M.
1993-09-15
This report discusses the Fermilab experiment E735 which is dedicated to the search for the quark-gluon plasma from proton-antiproton interactions; multifragmentation using the EOS-TPC; STAR R&D; silicon avalanche diodes as direct time-of-flight detectors; and soft photons at the AGS-E855.
Performance of quark/gluon discrimination in 13 TeV data
CMS Collaboration
2016-01-01
The 2015 proton collision data at 13 TeV and corresponding simulated samples are used to produce an updated quark/gluon jet discriminator and to validate its performances making use of dimuon plus jet and dijet selected events. The three input discriminating jet observables are the same as those used for the latest validated Run 1 discriminator, as well as the likelihood method to combine them. A new method is employed to derive data-driven corrections to the simulated distributions, and access corresponding systematic uncertainties.
Effects of a dressed quark-gluon vertex in vector heavy-light mesons
Gomez-Rocha, M; Krassnigg, A
2016-01-01
We extend earlier investigations of heavy-light pseudoscalar mesons to the vector case, using a simple model in the context of the Dyson-Schwinger-Bethe-Salpeter approach. We investigate the effects of a dressed-quark-gluon vertex in a systematic fashion and illustrate and attempt to quantify corrections beyond the phenomenologically very useful and successful rainbow-ladder truncation. In particular we investigate dressed quark photon vertex in such a setup and make a prediction for the experimentally as yet unknown mass of the B_c*, which we obtain at 6.334 GeV well in line with predictions from other approaches.
Exploring the Quark-Gluon Content of Hadrons: From Mesons to Nuclear Matter
Energy Technology Data Exchange (ETDEWEB)
Matevosyan, Hrayr [Louisiana State Univ., Baton Rouge, LA (United States)
2007-08-01
Even though Quantum Chromodynamics (QCD) was formulated over three decades ago, it poses enormous challenges for describing the properties of hadrons from the underlying quark-gluon degrees of freedom. Moreover, the problem of describing the nuclear force from its quark-gluon origin is still open. While a direct solution of QCD to describe the hadrons and nuclear force is not possible at this time, we explore a variety of developed approaches ranging from phenomenology to first principle calculations at one or other level of approximation in linking the nuclear force to QCD. The Dyson Schwinger formulation (DSE) of coupled integral equations for the QCD Green’s functions allows a non-perturbative approach to describe hadronic properties, starting from the level of QCD n-point functions. A significant approximation in this method is the employment of a finite truncation of the system of DSEs, that might distort the physical picture. In this work we explore the effects of including a more complete truncation of the quark-gluon vertex function on the resulting solutions for the quark 2-point functions as well as the pseudoscalar and vector meson masses. The exploration showed strong indications of possibly large contributions from the explicit inclusion of the gluon 3- and 4-point functions that are omitted in this and previous analyses. We then explore the possibility of extrapolating state of the art lattice QCD calculations of nucleon form factors to the physical regime using phenomenological models of nucleon structure. Finally, we further developed the Quark Meson Coupling model for describing atomic nuclei and nuclear matter, where the quark-gluon structure of nucleons is modeled by the MIT bag model and the nucleon many body interaction is mediated by the exchange of scalar and vector mesons. This approach allows us to formulate a fully relativistic theory, which can be expanded in the nonrelativistic limit to reproduce the well known phenomenological Skyrme
Institute of Scientific and Technical Information of China (English)
TAN Jia-Jin; LU Juan; CHENG Yan; ZHOU Li-Huan; ZHU Wen-Jun; MA Wei-Xing; GOU Qing-Quan
2008-01-01
Based on the quark-gluon structure of nucleon and the existence of Odderon in nucleon via gluon self-interaction, the elastic scattering of pp at high energies is studied. Our theoretical predictions reproduce experimental data perfectly. The contributions from individual terms of quark-quark, gluon-gluon interactions, quark-gluon interfer-ence and the Odderon terms to total cross section are analyzed. In addition to the leading quark-quark contribution, the Odderon contribution is quite important. In particular, the Odderon plays an essential role in fitting to data. Therefore, We may claim that the high energy lap and pp elastic scattering may be good processes to search for the Odderon, the three Reggeized gluon bound states.
Quark-gluon vertex dressing and meson masses beyond ladder-rainbow truncation
Energy Technology Data Exchange (ETDEWEB)
Hrayr Matevosyan; Anthony Thomas; Peter Tandy
2007-04-01
We include a generalized infinite class of quark-gluon vertex dressing diagrams in a study of how dynamics beyond the ladder-rainbow truncation influences the Bethe-Salpeter description of light quark pseudoscalar and vector mesons. The diagrammatic specification of the vertex is mapped into a corresponding specification of the Bethe-Salpeter kernel, which preserves chiral symmetry. This study adopts the algebraic format afforded by the simple interaction kernel used in previous work on this topic. The new feature of the present work is that in every diagram summed for the vertex and the corresponding Bethe-Salpeter kernel, each quark-gluon vertex is required to be the self-consistent vertex solution. We also adopt from previous work the effective accounting for the role of the explicitly non-Abelian three gluon coupling in a global manner through one parameter determined from recent lattice-QCD data for the vertex. With the more consistent vertex used here, the error in ladder-rainbow truncation for vector mesons is never more than 10% as the current quark mass is varied from the u/d region to the b region.
QCD sum rule calculation of quark-gluon three-body components in the B-meson wave function
Nishikawa, Tetsuo; Tanaka, Kazuhiro
2011-10-01
We discuss the QCD sum rule calculation of the heavy-quark effective theory parameters λE and λH, which represent quark-gluon three-body components in the B-meson wave function. We update the sum rules for λE,H calculating the new higher-order contributions to the operator product expansion for the corresponding correlator, i.e., the order αs radiative corrections to the Wilson coefficients associated with the dimension-5 quark-gluon mixed condensate, and the power corrections due to the dimension-6 vacuum condensates. We find that the new radiative corrections significantly improve stability of the corresponding Borel sum rules, modifying the values of λE,H.
Different methods for quark/gluon jet classification on real data from the DELPHI detector
Energy Technology Data Exchange (ETDEWEB)
Transtroemer, G
1999-05-01
Different methods to separate quark jets from gluon jets have been investigated and tested on data from the DELPHI experiment. A test sample of gluon jets was selected from bb-barg threejet events where the two b-jets had been identified using a lifetime tag and quark jet sample was obtained from qq-bar{gamma} events where the photon was required to have a high energy and to be well separated from the two jets. Three types of tests were made. Firstly, the jet energy, which is the variable most frequently used for quark/gluon jet separation, was compared with methods based of the differences in the fragmentation of quark and gluon jets. It was found that the fragmentation based classification provides significantly better identification than the jet energy only in events where the jets all have approximately the same energy. In Monte Carlo generated symmetric e{sup +}e{sup -} {yields} qq-barg threejet events, where the jet energy does not provide any identification at all, the gluon jet was correctly assigned in 58 % of the events. More important, however, is that the identification has been divided into two independent parts, the energy part and the fragmentation part. Secondly, two different sets of fragmentation sensitive variables were tested. It was found that a slightly better identification could be achieved using information from all the particles of the jet rather than using only the leading ones. Thirdly, three types of statistical discrimination methods were compared: a cut on a single fragmentation variable; a cut on the Fisher statistical discriminant calculated from one set of variables; a cut on the output from an Artificial Neural Networks (ANN) trained on different sets of variables. The three types of classifiers gave about the same performance and one conclusion from this study was that the use of ANNs or Fisher statistical discrimination do not seem to improve the results significantly in quark/gluon jet separation on a jet to jet basis 45 refs
Rojas, E; El-Bennich, B; Oliveira, O; Frederico, T
2013-01-01
We investigate the dressed quark-gluon vertex combining two established non-perturbative approaches to QCD: the Dyson-Schwinger equation (DSE) for the quark propagator and lattice-regularized simulations for the quark, gluon and ghost propagators. The vertex is modeled using a generalized Ball-Chiu ansatz parameterized by a single form factor $\\tilde X_0$ which effectively represents the quark-ghost scattering kernel. The solution space of the DSE inversion for $\\tilde X_0$ is highly degenerate, which can be dealt with by a numerical regularization scheme. We consider two possibilities: (i) linear regularization and (ii) the Maximum Entropy Method. These two numerical approaches yield compatible $\\tilde X_0$ functions for the range of momenta where lattice data is available and feature a strong enhancement of the generalized Ball-Chiu vertex for momenta below 1 GeV. Our ansatz for the quark-gluon vertex is then used to solve the quark DSE which yields a mass function in good agreement with lattice simulations...
Influence of vector interactions on the hadron-quark/gluon phase transition
Shao, G Y; Di Toro, M; Liu, B; Matera, F
2012-01-01
The hadron-quark/gluon phase transition is studied in the two-phase model. As a further study of our previous work, both the isoscalar and isovector vector interactions are included in the Polyakov loop modified Nambu--Jona-Lasinio model (PNJL) for the quark phase. The relevance of the exchange (Fock) terms is stressed and suitably accounted for. The calculation shows that the isovector vector interaction delays the phase transition to higher densities and the range of the mixed phase correspondingly shrinks. Meanwhile the asymmetry parameter of quark matter in the mixed phase decreases with the strengthening of this interaction channel. This leads to some possible observation signals being weakened, although still present. We show that these can be rather general effects of a repulsion in the quark phase due to the symmetry energy. This is also confirmed by a simpler calculation with the MIT--Bag model. However, the asymmetry parameter of quark matter is slightly enhanced with the inclusion of the isoscalar ...
Quark-gluon mixed condensate for the SU(2) light-flavor sector at finite temperature
Nam, Seung-il
2013-01-01
We investigate the quark-gluon mixed condensate m^2_0 = for the SU(2) light-flavor sector at finite temperature (T). Relevant model parameters, such as the average (anti)instanton size, inter-(anti)instanton distance, and constituent-quark mass at zero virtuality, are modified as functions of T, employing the trivial-holonomy caloron solution. By doing that, we observe correct chiral restoration patterns depending on the current-quark mass m. We also perform the two-loop renormalization-group (RG) evolution for the both condensates by increasing the renormalization scale mu=(0.6~2.0) GeV. It turns out that the mixed condensate is insensitive to the RG evolution, whereas the quark condensate become larger considerably by the evolution. Numerically, we obtain -^1/5 = (0.45 ~ 0.46) GeV at T=0 within the present theoretical framework, and the mixed condensate plays the role of the chiral order parameter for finite T. The ratio of the two condensates m^2_0 is almost flat below the chiral transition T (T_0), and ...
OZI violation in low energy omega and phi production in the pp system in a quark-gluon model
Dillig, M
2006-01-01
We investigate OZI violation in near-threshold omega and phi production in the pp system. Assuming ideal omega/phi mixing (corrections are estimated), the energy dependence of the ratio R(omega/phi) is analyzed in a perturbative quark-gluon exchange model up to the third other in the strong coupling constant alpha(s) with the proton represented as a quark - scalar diquark system. We give a very natural explanation of the violation of the OZI rule in omega/phi production and its energy dependence near the production thresholds.
Comparison of Jet Quenching Formalisms for a Quark-Gluon Plasma "Brick"
Armesto, Nestor; Gale, Charles; Horowitz, William A.; Jacobs, Peter; Jeon, Sangyong; van Leeuwen, Marco; Majumder, Abhijit; Muller, Berndt; Qin, Guang-You; Salgado, Carlos A.; Schenke, Bjorn; Verweij, Marta; Wang, Xin-Nian; Wiedemann, Urs Achim
2012-01-01
We review the currently available formalisms for radiative energy loss of a high-momentum parton in a dense strongly interacting medium. The underlying theoretical framework of the four commonly used formalisms is discussed and the differences and commonalities between the formalisms are highlighted. A quantitative comparison of the single gluon emission spectra as well as the energy loss distributions is given for a model system consisting of a uniform medium with a fixed length of L=2 fm and L=5 fm (the `Brick'). Sizable quantitative differences are found. The largest differences can be attributed to specific approximations that are made in the calculation of the radiation spectrum.
The role of noise and dissipation in the hadronization of the quark-gluon plasma
Fraga, E S
2006-01-01
We discuss the role of noise and dissipation in the explosive spinodal decomposition scenario of hadron production during the chiral transition after a high-energy heavy ion collision. We use a Langevin description inspired by nonequilibrium field theory to perform real-time lattice simulations of the behavior of the chiral fields. Preliminary results for the interplay between additive and multiplicative noise terms, as well as for non-Markovian corrections, are also presented.
A chiral matrix model of the semi-Quark Gluon Plasma in QCD
Pisarski, Robert D
2016-01-01
A chiral matrix model applicable to QCD with 2+1 flavors is developed. This requires adding a SU(3)_L x SU(3)_R x Z(3)_A nonet of scalar fields, with both parities, and coupling these to quarks through a Yukawa coupling, y. Treating the scalar fields in mean field approximation, the effective Lagrangian is computed by integrating out quarks to one loop order. In addition to the usual symmetry breaking term, linear in the current quark mass m_qk, at a nonzero temperature T it is necessary to add a new term, ~ m_qk T^2. The parameters of the gluon part of the matrix model, including especially the deconfining transition temperature T_d = 270 MeV, are identical to that for the pure glue theory without quarks. The parameters in the chiral matrix model are fixed by the values, at zero temperature, of the pion decay constant the masses of the pions, kaons, eta, and eta'. The temperature for the chiral crossover at T_chi = 155 MeV is determined by adjusting the Yukawa coupling y. We find reasonable agreement with th...
Relativity matters from Einstein's EMC2 to laser particle acceleration and quark-gluon plasma
Rafelski, Johann
2017-01-01
Rafelski presents Special Relativity in a language deemed accessible to students without any topical preparation - avoiding the burden of geometry, tensor calculus, and space-time symmetries – and yet advancing in highly contemporary context all the way to research frontiers. Special Relativity is presented such that nothing remains a paradox or just apparent, but rather is explained. A text of similar character, content, and scope, has not been available before. This book describes Special Relativity when rigid material bodies are introduced describing the reality of body contraction; it shows the relevance of acceleration and the necessary evolution of the theoretical framework when acceleration is critical. This book also presents the evolving views of Einstein about the aether. In addition to a careful and elementary introduction to relativity complete with exercises, worked examples and many discussions, this volume connects to current research topics so that readers can explore Special Relativity fr...
Static quark-antiquark potential in the quark-gluon plasma from lattice QCD.
Burnier, Yannis; Kaczmarek, Olaf; Rothkopf, Alexander
2015-02-27
We present a state-of-the-art determination of the complex valued static quark-antiquark potential at phenomenologically relevant temperatures around the deconfinement phase transition. Its values are obtained from nonperturbative lattice QCD simulations using spectral functions extracted via a novel Bayesian inference prescription. We find that the real part, both in a gluonic medium, as well as in realistic QCD with light u, d, and s quarks, lies close to the color singlet free energies in Coulomb gauge and shows Debye screening above the (pseudo)critical temperature T_{c}. The imaginary part is estimated in the gluonic medium, where we find that it is of the same order of magnitude as in hard-thermal loop resummed perturbation theory in the deconfined phase.
Thermodynamics and equations of state of matter from ideal gas to quark-gluon plasma
Fortov, Vladimir
2016-01-01
The monograph presents a comparative analysis of different thermodynamic models of the equations of state. The basic ideological premises of the theoretical methods and the experiment are considered. The principal attention is on the description of states that are of greatest interest for the physics of high energy concentrations which are either already attained or can be reached in the near future in controlled terrestrial conditions, or are realized in astrophysical objects at different stages of their evolution. Ultra-extreme astrophysical and nuclear-physical applications are also analyzed where the thermodynamics of matter is affected substantially by relativism, high-power gravitational and magnetic fields, thermal radiation, transformation of nuclear particles, nucleon neutronization, and quark deconfinement. The book is intended for a wide range of specialists engaged in the study of the equations of state of matter and high energy density physics, as well as for senior students and postgraduates.
Describing the dynamics of the Quark-Gluon Plasma using relativistic viscous hydrodynamics
Yarbrough, Katherine Michelle
Shock diamonds occur in over- or under- expanded supersonic flow. They occur in the unsteady jet of a pulse detonation engine, displaying an array of complex features. Due to the highly transient nature of the flow, it must be captured using high-speed cinematography. A study of image processing of shock reflection in unsteady flow is presented. Using a computer-based environment, a method was developed to process images of shock waves to pinpoint where the shock wave starts. Using mathematical methods, such as Abel transforms, a computer code, written in Matlab, was developed to accurately transform the images to detect density distributions in the form of shock waves. The Mach number and specific heat, pressure, temperature, and density ratios were found using shock polars. Evolution of the flow was examined by transforming images to follow the flow patterns. Seven images were selected and analyzed with the methods developed in this thesis. Then a comparison was done by tracking particles seeded in the flow. The particle tracking revealed velocities which were compared to the Mach numbers found using the shock polars.
Direct Photon Anisotropy and the Time Evolution of the Quark-Gluon Plasma
AUTHOR|(INSPIRE)INSPIRE-00360979
2016-07-22
Historically, the thermal photon inverse slope parameter has been interpreted as the thermalization temperature of the QGP. Observation of the thermal photon spectrum in nucleus-nucleus collisions at the ALICE and PHENIX experiments obtain the inverse slope parameter, but the obtained values are inconsistent with the thermalization temperature predicted by the hydrodynamic model. It has therefore been argued that the inverse slope parameter is not representative of the true QGP thermalization temperature because not all thermal photons are emitted at thermalization. This research will probe this assertion using an investigation of flow and nuclear suppression of thermal photons from ALICE Pb-Pb collisions at '\\sqrt{s_{NN}}=2.76' TeV and comparison to p-p data at '\\sqrt{s_{NN}}=2.76' TeV.
Unified Description of Charmonium Suppression in Quark-Gluon Plasma Medium at RHIC and LHC Energies
Singh, Captain R.; Srivastava, P. K.; Ganesh, S; Mishra, M.
2015-01-01
Recent experimental and theoretical studies suggest that the quarkonia suppression in a thermal QCD medium created at heavy ion collisions is a complex interplay of various physical processes. In this article we put together most of these processes in a unified way to calculate the charmonium survival probability (nuclear modification factor) at energies available at relativistic heavy ion collider (RHIC) and large hadron collider (LHC) experiments. We have included shadowing as the dominant ...
Dynamical energy loss as a novel Quark-Gluon Plasma tomographic tool
Djordjevic, Magdalena
2016-12-01
High momentum suppression of light and heavy flavor observables is considered to be an excellent probe of jet-medium interactions in QCD matter created at RHIC and LHC. Utilizing this tool requires accurate suppression predictions for different experiments, probes and experimental conditions, and their unbiased comparison with experimental data. With this goal, we developed the dynamical energy loss formalism towards generating predictions for non-central collisions; the formalism takes into account both radiative and collisional energy loss computed within the same theoretical framework, dynamical (as opposed to static) scattering centers, finite magnetic mass, running coupling and uses no free parameters in comparison with experimental data. Within this formalism, we provided predictions, and a systematic comparison with experimental data, for a diverse set of suppression data: all available light and heavy flavor probes, lower and high momentum ranges, various centrality ranges and various collision energies at RHIC and LHC. We here also provide clear qualitative and quantitative predictions for soon to become available LHC experimental data. Comprehensive agreement between our predictions and experimental results provides a good deal of confidence that our dynamical energy loss formalism can well explain the jet-medium interactions in QGP, which will be further tested by the obtained predictions for the upcoming data. Application of this model, as a novel high-precision tomographic tool of QGP medium, are also discussed.
Hot QCD equation of state and quark-gluon plasma-- finite quark chemical potential
Chandra, Vinod
2008-01-01
We explore the relevance of a hot QCD equation of state of $O[g^6\\ln(1/g)]$, which has been obtained\\cite{avrn} for non-vanishing quark-chemical potentials to heavy ion collisions. Employing a method proposed in a recent paper \\cite{chandra1}, we use the EOS to determine a host of thermodynamic quantities, the energy density, specific heat, entropy dnesity, and the temperature dependence of screening lengths, with the behaviour of QGP at RHIC and LHC in mind. We also investigate the sensitivity of these observables to the quark chemical potential.
From the QCD vacuum to (strongly coupled) quark-gluon plasma
Shuryak, Edward
2005-04-01
I start with brief discussion of the role of topological objects in the QCD vacuum, reminding why instantons play a special role in chiral symmetry breaking and hadronic physics. Then I move to high temperature T > T c domain, describing briefly some experimental discoveries made at RHIC such as robust collective flow phenomena. They are well described by ideal hydrodynamics, with the Equation of State (EoS) in good agreement with that predicted by lattice simulations. However for hydro to work the transport properties of QGP should be quite remarkable. These and other theoretical developments, especially based on lattice simulations, indicate that matter produced at RHIC is a strongly coupled liquid, sQGP for short. Existence of "new spectroscopy" of states, most of them colored, is expected. We also briefly discuss two other "strongly coupled systems", (i) the strongly coupled supersymmetric theories studied via Maldacena duality; (ii) trapped ultra-cold atoms with very large scattering length.
Short path length pQCD corrections to energy loss in the quark gluon plasma
Kolbe, Isobel
2015-01-01
Recent surprising discoveries of collective behaviour of low-$p_T$ particles in $pA$ collisions at LHC hint at the creation of a hot, fluid-like QGP medium. The seemingly conflicting measurements of non-zero particle correlations and $R_{pA}$ that appears to be consistent with unity demand a more careful analysis of the mechanisms at work in such ostensibly minuscule systems. We study the way in which energy is dissipated in the QGP created in $pA$ collisions by calculating, in pQCD, the short separation distance corrections to the well-known DGLV energy loss formulae that have produced excellent predictions for $AA$ collisions. We find that, shockingly, due to the large formation time (compared to the $1/\\mu$ Debye screening length) assumption that was used in the original DGLV calculation, a highly non-trivial cancellation of correction terms results in a null short path length correction to the DGLV energy loss formula. We investigate the effect of relaxing the large formation time assumption in the final ...
Lower vs. high momentum mass tomography in Quark-Gluon Plasma
Djordjevic, Magdalena; Zivkovic, Lidija
2016-01-01
We here show that at lower energies single particle suppression for different types of probes exhibit a clear mass hierarchy, which is a direct consequence of the differences in the energy loss, rather than the differences in the initial distributions. On the other hand, we predict that the mass hierarchy is not expected at high energies; i.e. the probes of different masses exhibit nearly the same suppression once high momentum measurements are considered. Moreover, we also argue that the same insensitivity on the probe types is valid for jets as well. In particular, the experimental data in the momentum regions where they exist for both types of probes, show similar suppressions of charged hadrons and inclusive jet data. Finally, the available jet data also show (though with large error bars) an overlap between b-jets (heavy) and inclusive jets (light), which we predict will also be exhibited for soon-to-be-measured charm jets. Consequently, our results suggest that single particles in the momentum region be...
Some Applications of Hard Thermal Loop Perturbation Theory in Quark Gluon Plasma
Haque, Najmul
2014-01-01
This thesis is mainly devoted to the study of thermodynamics for quantum Chromodynamics. In this thesis I apply hard-thermal-loop perturbation theory, which is a gauge-invariant reorganization of the conventional perturbative expansion for quantum gauge theories to study the thermodynamics of QCD in leading-order, next-to-leading-order and next-to-next-to-leading order at finite temperature and finite chemical potential. I also discuss about various order diagonal and off-diagonale quark number susceptibilities in leading order as well as beyond leading order. For all the observables, I compare our results with available lattice QCD data and we find good agreement. Along-with the computation of thermodynamic quantities of hot and dense matter, I also discuss about low mass dilepton rate from hot and dense medium using both perturbative and non-perturbative models and compare them with those from lattice gauge theory and in-medium hadron gas.
Globally Polarized Quark-gluon Plasma in Non-central A+ACollisions
Energy Technology Data Exchange (ETDEWEB)
Liang, Zuo-tang; Wang, Xin-Nian
2004-10-01
Produced partons have large local relative orbital angular momentum along the direction opposite to the reaction plane in the early stage of non-central heavy-ion collisions. Parton scattering is shown to polarize quarks along the same direction due to spin-orbital coupling.Such global quark polarization will lead to many observable consequences,such as left-right asymmetry of hadron spectra, global transverse polarization of thermal photons, dileptons and hadrons. Hadrons from the decay of polarized resonances will have azimuthal asymmetry similar to the elliptic flow. Global hyperon polarization is predicted with indifferent hadronization scenarios and can be easily tested.
Where does the rho go? Chirally symmetric vector mesons in the quark-gluon plasma
Pisarski, R D
1995-01-01
If the phase transition of QCD at nonzero temperature is dominated by the (approximate) restoration of chiral symmetry, then the transition might be characterized using a gauged linear sigma model. Assuming that vector meson dominance holds, such sigma models predict that at the temperature of chiral restoration, the pole mass of the thermal \\rho meson is greater than that at zero temperature; in the chiral limit and in weak coupling this mass is \\sim 962 \\, MeV. The width of the thermal \\rho-a_1 peak is estimated to be about 200 - 250 \\, MeV.
Jet-evolution in the quark-gluon plasma from RHIC to the LHC
Energy Technology Data Exchange (ETDEWEB)
Domdey, S. [Institute for Theoretical Physics, University of Heidelberg (Germany); Kopeliovich, B.Z. [Institute for Theoretical Physics, University of Heidelberg (Germany); Departamento de Fisica, Universidad Tecnica Federico Santa Maria, Instituto de Estudios Avanzados en Ciencias e Ingenieria, Centro Cientifico-Tecnologico de Valparaiso, Casilla 110-V, Valparaiso (Chile); Pirner, H.J., E-mail: pir@tphys.uni-heidelberg.d [Institute for Theoretical Physics, University of Heidelberg (Germany)
2011-04-15
The observed suppression of high{sub pperpendicular} hadrons allows different explanations. We discuss two possible scenarios: In scenario 1, parton energy loss from scattering in the hot medium is complemented by final state interactions in the resonance matter. Scenario 2 has an enhanced transport parameter q-hat which is fitted to RHIC data. For LHC, the two scenarios lead to very different predictions for the nuclear modification factor of hadrons. In addition, jet reconstruction allows more specific tests of the mechanisms responsible for jet quenching. We calculate the distribution of partons inside a jet and find different results for the two scenarios.
Initial temperature of the strongly interacting Quark Gluon Plasma created at RHIC
Csanad, Mate
2011-01-01
A 1+3 dimensional solution of relativistic hydrodynamics is analyzed in this paper. Momentum distribution and other observables are calculated from the solution and compared to hadronic measurements from the Relativistic Heavy Ion Collider (RHIC). The solution is compatible with the data, but only the freeze-out point of the evolution is determined. Many equation of states and initial states (initial temperatures) are valid with the same freeze-out distribution, thus the same hadronic observables. The observable that would distinguish between these initial temperatures is momentum distribution of photons, as photons are created throughout the evolution of the fireball created in RHIC collisions. The PHENIX experiment at RHIC measures such data via low invariant mass e+e- pairs. Average temperature from this data is T=221+-23+-18 MeV, while a model calculation with initial temperature 370 MeV agree with the data.
Heavy flavours production in quark-gluon plasma formed in high energy nuclear reactions
Kloskinski, J.
1985-01-01
Results on compression and temperatures of nuclear fireballs and on relative yield of strange and charmed hadrons are given . The results show that temperatures above 300 MeV and large compressions are unlikely achieved in average heavy ion collision. In consequence, thermal production of charm is low. Strange particle production is, however, substantial and indicates clear temperature - threshold behavior.
New Basic Physics Derived from Laser Plasma Interaction (lirpp Vol. 10)
Hora, Heinrich
2016-10-01
The following sections are included: * INTRODUCTION * VARIOUS PHENOMENA * COMPLETION OF THE EQUATION OF MOTION BY NONLINEAR FORCES * NONLINEAR PRINCIPLE * CONTAINMENT FORCE OF HADRONS IN NUCLEI AND PHASE TRANSITION INTO QUARK GLUON PLASMA * Acknowledgements * References
Kondrashova, Nataliia; Haller, Johannes
2016-01-01
A measurement of the differential cross-section of $pp \\rightarrow Z/\\gamma^{*}(\\rightarrow e^{+}e^{-})$~+~jet production and a study of the jet quark-gluon decomposition are presented. The data of 21.3 $\\mathrm{fb^{-1}}$ collected with the ATLAS detector at the Large Hadron Collider in 2012 at the centre-of-mass energy $\\sqrt{s} = 8$~TeV are used.The double-differential $pp \\rightarrow Z/\\gamma^{*}(\\rightarrow e^{+}e^{-})$~+~jet cross-section is measured as a function of the absolute rapidity and the transverse momentum of jets. The jet quark-gluon decomposition study is performed in bins of the transverse momentum and the absolute rapidity of the highest-$p_{T}$ jet. The possibility to distinguish between quark-initiated and gluon-initiated jets is especially important for beyond Standard Mode searches, where a lot of signal processes have quarks in the final states, while background processes in Quantum Chromodynamic have mostly gluons. The performance of the discrimination between these two types of jets ...
Kondrashova, Nataliia; Haller, Johannes
2016-01-01
A measurement of the differential cross-section of $pp \\rightarrow Z/\\gamma^{*}(\\rightarrow e^{+}e^{-})$~+~jet production and a study of the jet quark-gluon decomposition are presented. The data of 21.3 $\\mathrm{fb^{-1}}$ collected with the ATLAS detector at the Large Hadron Collider in 2012 at the centre-of-mass energy $\\sqrt{s} = 8$~TeV are used.The double-differential $pp \\rightarrow Z/\\gamma^{*}(\\rightarrow e^{+}e^{-})$~+~jet cross-section is measured as a function of the absolute rapidity and the transverse momentum of jets. The jet quark-gluon decomposition study is performed in bins of the transverse momentum and the absolute rapidity of the highest-$p_{T}$ jet. The possibility to distinguish between quark-initiated and gluon-initiated jets is especially important for beyond Standard Mode searches, where a lot of signal processes have quarks in the final states, while background processes in Quantum Chromodynamic have mostly gluons. The performance of the discrimination between these two types of jets ...
Energy Technology Data Exchange (ETDEWEB)
EN YO,H.; SAITO,N.; SHIBATA,T.A.; YAZAKI,K.; BUNCE,G.
2002-03-29
The RIKEN School on ''Quark-Gluon Structure of the Nucleon and QCD'' was held from March 29th through 31st at the Nishina Memorial Hall of RIKEN, Wako, Saitama, Japan, sponsored by RIKEN (the Institute of Physical and Chemical Research). The school was the second of a new series with a broad perspective of hadron and nuclear physics. The purpose of the school was to offer young researchers an opportunity to learn theoretical aspects of hadron physics based on QCD and related experimental programs being or to be carried out by Japanese groups. We had 3 theoretical courses, each consisting of 3 one-hour lectures, and 6 experimental courses, each consisting of a one-hour lecture.
Results of the NA49 experiment on the search for the quark-gluon plasma at the CERN SPS
Seyboth, P
2001-01-01
Experiment NA49 at the CERN SPS has performed large acceptance measurements of hadron production in Pb+Pb collisions at 40 and 158 A.GeV beam energies. These data allowed a study of the space-time evolution, the hadro-chemical composition and event-by-event fluctuations of average event properties of the created hadron system. Results at top SPS energy are consistent with the existence of a transient deconfined phase in the early stage of the reaction. (22 refs).
Song, Jun; Liang, Zuo-tang
2014-01-01
We propose a new kind of two-particle correlation of identified hadrons in longitudinal rapidity space, called $G_{\\alpha\\beta}(y_{\\alpha},y_{\\beta})$, which can reflect clearly the charge correlations of hot quark system produced in AA collisions at LHC energies. It is derived from the basic scenario of quark combination mechanism of hadron production. Like the elliptic flow of identified hadrons at intermediate transverse momentum, this correlation is independent of the absolute hadronic yields but dependent only on the flavor compositions of hadrons, and thus exhibits interesting properties for different kinds of hadron species. We suggest the measurement of this observable in AA collisions at LHC to gain more insights into the charge correlation properties of produced hot quark matter.
Singh, R., Captain; Srivastava, P. K.; Ganesh, S.; Mishra, M.
2015-09-01
Recent experimental and theoretical studies suggest that the quarkonium suppression in a thermal QCD medium created in heavy ion collisions is a complex interplay of various physical processes. In this article we put together most of these processes in a unified way to calculate the charmonium survival probability (nuclear modification factor) at energies available at Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC) experiments. We include shadowing as the dominant cold-nuclear-matter effect. Further, gluonic dissociation and collision damping are included, which provide width to the spectral function of charmonia in a thermal medium and cause the dissociation of charmonium along with the usual color screening. We include color screening by using our recently proposed modified Chu-Matsui model. Furthermore, we incorporate the recombination of uncorrelated charm and anticharm quarks for the regeneration of charmonium over the entire temporal evolution of the QGP medium. Finally, we do a feed-down correction from the excited states to calculate the survival probability of charmonium. We find that our unified model suitably and simultaneously describes the experimental nuclear modification data of J /ψ at RHIC and LHC.
Mathews, Grant J.; Meixner, Matthew; Olson, J. Pocahontas; Lan, Nguyen Q.; Dalhed, Holister E.
2013-10-01
We present an updated and improved equation of state (which we call the NDL EoS) for use in neutron-star structure and core-collapse supernova simulations. This EoS is begins with a framework originally developed by Bowers & Wilson, but there are numerous changes. Among them are: (1) a reformulation in the context of density functional theory; (2) the possibility of the formation of material with a net proton excess (Ye > 0 . 5); (3) an improved treatment of the nuclear statistical equilibrium and the transition to heavy nuclei as the density approaches nuclear matter density; (4) an improved treatment of the effects of pions in the regime above nuclear matter density including the incorporation of all the known mesonic and baryonic states at high temperature; (5) the effects of 3-body nuclear forces at high densities; and (6) the possibility of a first-order or crossover transition to a QCD chiral symmetry restoration and deconfinement phase at densities above nuclear matter density. This paper details the physics of, and constraints on, this new EoS and describes its implementation in numerical simulations. We show comparisons of this EoS with other equations of state commonly used in supernova collapse simulations. Work at the University of Notre Dame is supported by the U.S. Department of Energy under Nuclear Theory Grant DE-FG02-95-ER40934.
Quasi-Particle Degrees of Freedom versus the Perfect Fluid as Descriptors of the Quark-Gluon Plasma
Levy, L A Linden; Rosen, C; Steinberg, P
2007-01-01
Approaches for understanding the hydrodynamic flow of the hot and dense medium created in the collisions of relativistic heavy ions are discussed, focusing on their implications for scenarios where quasi-particles are assumed to carry the thermodynamic degrees of freedom. Well-defined quasi-particle degrees of freedom are in principle inconsistent with inviscid hydrodynamics, which implies a vanishing mean free path. However, quasi-particles may play a role as the density of the medium decreases. It is thus an open question whether the freeze-out of the fluid stage proceeds directly into hadrons, or via a fleeting intermediate state with effectively-free constituent quarks, which may well be identified with QCD quasi-particle degrees of freedom. The empirical observation of the ``$n_q$'' scaling of elliptic flow \\cite{Adare:2006ti} (the universality of $v_2/n_q$ as a function of $(m_{T}-m)/n_q$, where $n_q$ is the number of constituent quarks in the hadron) is scrutinized in detail. It is found that, at all t...
The interfacial surface tension of a quark-gluon plasma ﬁreball in a hadronic medium
Indian Academy of Sciences (India)
R Ramanathan; K K Gupta; Agam K Jha; S S Singh
2007-05-01
We calculate the interfacial surface tension of a QGP-ﬁreball in a hadronic medium in the Ramanathan et al statistical model. The constancy of the ratio of the surface tension with the cube of the critical transition temperature is in overall accordance with lattice QCD ﬁndings. It is in complete agreement with a recent MIT bag model calculation of surface tension. The velocity of sound in the QGP droplet is predicted to be in the range (0.27 ± 0.02) times the velocity of light in vacuum and this value is independent of both the value of the transition temperature and the model parameters.
Energy Technology Data Exchange (ETDEWEB)
Kondrashova, Nataliia
2016-04-15
A measurement of the differential cross-section of pp→Z/γ{sup *}(→e{sup +}e{sup -})+jet production and a study of the jet quark-gluon decomposition are presented. The data of 21.3 fb{sup -1} collected with the ATLAS detector at the Large Hadron Collider in 2012 at the centre-of-mass energy √(s)=8 TeV are used. The double-differential pp→Zγ{sup *}(→e{sup +}e{sup -})+jet cross-section is measured as a function of the absolute rapidity and the transverse momentum of jets. The jet quark-gluon decomposition study is performed in bins of the transverse momentum and the absolute rapidity of the highest-p{sub T} jet. The possibility to distinguish between quark-initiated and gluon-initiated jets is especially important for beyond Standard Mode searches, where a lot of signal processes have quarks in the final states, while background processes in Quantum Chromodynamic have mostly gluons. The performance of the discrimination between these two types of jets using different jet properties is studied using data-driven techniques with purified quark-like and gluon-like jet samples. The pp→Z/γ{sup *}(→e{sup +}e{sup -})+jet production provides an important test of perturbative Quantum Chromodynamics and is an important background for many Standard Model processes and beyond Standard Model searches. In addition, the measurement of the pp→Z/γ{sup *}(→e{sup +}e{sup -})+jet cross section as a function of the absolute rapidity and the transverse momentum of inclusive jets provides constraints on the uncertainties on the parton distribution functions. The rapidity of jets provides the information on the fraction of the initial proton's momentum carried by the interacting partons, which provides the sensitivity to the parton distribution functions, while the transverse momentum of jets allows to probe different transfer momentum scales.The measured cross-section is compared to the predictions from Monte Carlo generators based on leading order matrix elements
Energy Technology Data Exchange (ETDEWEB)
NONE
1996-10-01
This report summarizes the work on experimental research in intermediate energy nuclear physics carried out by New Mexico State University from April 1, 1994, through March 31, 1996 under a grant from the US Department of Energy. During this period we began phasing out our programs of study of pion-nucleus and pion-nucleon interaction and of nucleon-nucleus charge-exchange reactions, which have been our major focus of the past two or three years. At the same time we continued moving in a new direction of research on studies of the internal structure of nucleons and nuclei in terms of quarks and gluons. The pion and nucleon work has been aimed at improving our understanding of the nature of pion and proton interactions in the nuclear medium and of various aspects of nuclear structure. The studies of the quark-gluon structure of nucleons are aimed at clarifying such problems as the nature of the quark sea and the relation of the nucleon spin to the spins of the quarks within the nucleon, questions which are of a very fundamental nature.
Viscosity over entropy ratio in a quark plasma
Czerski, P.; Alberico, W. M.; Chiacchiera, S.; DePace, A.; Hansen, H.; Molinari, A.; Nardi, M.
2009-02-01
The quark viscosity in the quark-gluon plasma is evaluated in the hard thermal loop (HTL) approximation. The different contributions to the viscosity arising from the various components of the quark spectral function are discussed. The calculation is extended to finite values of the chemical potential.
Quark-Gluon Mixed Vacuum Condensates in Dyson-Schwinger Equations%在Dyson-Schwinger方程中夸克-胶子的混合真空凝聚
Institute of Scientific and Technical Information of China (English)
周丽娟; 马维兴
2005-01-01
基于夸克传播子的Dyson-Schwinger方程,计算了夸克胶子混合真空凝聚和夸克真空凝聚.这些凝聚不仅联系着夸克在真空态中的虚度,而且也表征了真空中夸克分布的空间宽度.真空凝聚的存在直接反映着QCD真空的非微扰结构. 计算表明:上夸克与下夸克的虚度为λ2u,d=0.7GeV2, 奇异夸克的虚度为λ2s=1.6GeV2.这些结果与许多用完全不同的方法得到的结果一致.%Based on Dyson-Schwinger Equations of quark propagator, we calculate quark-gluon mixed vacuum condensates 〈0|∶gsσμνGμνq∶|0〉 and quark vacuum condensates 〈0|∶q∶|0〉 which are not only related to virtuality of quark in vacuum state but also characterize the space width of quark distribution in the vacuum. The existence of these vacuum condensates reflects in a direct way the non-perturbative structure of QCD vacuum. Our calculated results on the mixed condensates lead to quark virtualities of λ2u,d=0.7GeV2 for u,d quarks, and λ2s=1.6GeV2 for s quark which are consistent with other's calculations using completely different methods.
Survival of Bc mesons in a hot plasma within a potential model
Alberico, W M; Czerski, P; De Pace, A; Nardi, M; Ratti, C
2013-01-01
We extend a previous work on the study of heavy charmonia and bottomonia in a deconfined quark-gluon plasma by considering the Bc family of mesons. With the introduction of this bound state of a charm and a beauty quark, we investigate at finite temperature the behavior of the quarkonium, in an energy region between the {\\psi} and the {\\Upsilon} states.
Thermodynamics of the N=2^* strongly coupled plasma
Buchel, A; Kerner, P; Liu, J T; Buchel, Alex; Deakin, Stan; Kerner, Patrick; Liu, James T.
2007-01-01
Gauge/string duality is a potentially important framework for addressing the properties of the strongly coupled quark gluon plasma produced at RHIC. However, constructing an actual string theory dual to QCD has so far proven elusive. In this paper, we take a partial step towards exploring the QCD plasma by investigating the thermodynamics of a non-conformal system, namely the N=2^* theory, which is obtained as a mass deformation of the conformal N=4 gauge theory. We find that at temperatures of order the mass scale, the thermodynamics of the mass deformed plasma is surprisingly close to that of the conformal gauge theory plasma. This suggests that many properties of the quark gluon plasma at RHIC may in fact be well described by even relatively simple models such as that of the conformal N=4 plasma.
Pre-equilibrium plasma dynamics
Energy Technology Data Exchange (ETDEWEB)
Heinz, U.
1986-01-01
Approaches towards understanding and describing the pre-equilibrium stage of quark-gluon plasma formation in heavy-ion collisions are reviewed. Focus is on a kinetic theory approach to non-equilibrium dynamics, its extension to include the dynamics of color degrees of freedom when applied to the quark-gluon plasma, its quantum field theoretical foundations, and its relationship to both the particle formation stage at the very beginning of the nuclear collision and the hydrodynamic stage at late collision times. The usefulness of this approach to obtain the transport coefficients in the quark-gluon plasma and to derive the collective mode spectrum and damping rates in this phase are discussed. Comments are made on the general difficulty to find appropriated initial conditions to get the kinetic theory started, and a specific model is given that demonstrates that, once given such initial conditions, the system can be followed all the way through into the hydrodynamical regime. 39 refs., 7 figs. (LEW)
Bleibel, J.; Bravina, L. V.; Zabrodin, E. E.
2016-06-01
Multiplicity, rapidity and transverse momentum distributions of hadrons produced both in inelastic and nondiffractive p p collisions at energies from √{s }=200 GeV to 14 TeV are studied within the Monte Carlo quark-gluon string model. Good agreement with the available experimental data up to √{s }=13 TeV is obtained, and predictions are made for the collisions at top LHC energy √{s }=14 TeV . The model indicates that Feynman scaling and extended longitudinal scaling remain valid in the fragmentation regions, whereas strong violation of Feynman scaling is observed at midrapidity. The Koba-Nielsen-Olesen (KNO) scaling in multiplicity distributions is violated at LHC also. The origin of both maintenance and violation of the scaling trends is traced to short range correlations of particles in the strings and interplay between the multistring processes at ultrarelativistic energies.
Vovchenko, V; Satarov, L M; Mishustin, I N; Csernai, L P; Kisel, I; Stoecker, H
2016-01-01
We study the possibility that partonic matter produced at early stage of ultrarelativistic heavy-ion collisions is out of chemical equilibrium. It is assumed that initially this matter is mostly composed of gluons, but quarks and antiquarks are produced at later times. The dynamical evolution of partonic system is described by the Bjorken-like ideal hydrodynamics with a time dependent quark fugacity. The results of this model are compared with those obtained by assuming the complete chemical equilibrium of partons already at the initial stage. It is shown that in a chemically non-equilibrium scenario the entropy gradually increases, and about 25% of the total final entropy is generated during the hydrodynamic evolution of deconfined matter. We argue that the (anti)quark suppression included in this approach may be responsible for reduced (anti)baryon to meson ratios observed in heavy-ion collisions at LHC energies.
Takahashi, Y.; Eby, P. B.
1985-01-01
Possibilities of observing abundances of phi mesons and narrow hadronic pairs, as results of QGP and Chiral transitions, are considered for nucleus-nucleus interactions. Kinematical requirements in forming close pairs are satisfied in K+K decays of S(975) and delta (980) mesons with small phi, and phi (91020) mesons with large PT, and in pi-pi decays of familiar resonance mesons only in a partially restored chiral symmetry. Gluon-gluon dominance in QGP can enhance phi meson production. High hadronization rates of primordial resonance mesons which form narrow hadronic pairs are not implausible. Past cosmic ray evidences of anomalous phi production and narrow pair abundances are considered.
The eigenmass of plasmon in the quark-gluon plasma%QGP中等离子激元的本征质量
Institute of Scientific and Technical Information of China (English)
方洁; 刘绘; 方芳; 孙红
2002-01-01
在QGP动力论框架下,既讨论了夸克质量等于零时,QGP中等离子激元的本征质量的解析表达式及其它对化学势和温度的依赖关系,又研究了夸克质量不等于零,如在讨论奇异夸克物质时,应考虑奇异夸克数s,通过对化学势,温度及相关量赋值,计算了QGP中等离子激元的本征质量的数值积分,作出了本征质量的等化学势,等温度线,分析了夸克和胶子对本征质量贡献的大小,并与夸克质量为零时的极端相对论情况作了比较.
夸克-胶子等离子体中的喷注-光子转换机制%Jet-photon Conversion in Expanding Quark-gluon Plasma
Institute of Scientific and Technical Information of China (English)
傅永平; 李云德
2010-01-01
提出了一种夸克-胶子等离子体中的喷注-光子转换机制.对于热光子而言,在热夸克-胶子媒介中的喷注-光子转换是一个非常重要的热光子来源.喷注可以通过次级康普顿散射和湮灭过程来实现喷注-光子转换.此外,还考虑了在快光子产生过程中起重要修正作用的胶子-光子贡献,其中,核遮蔽效应和同位旋效应也被引入到了部分子模型中.
Berrehrah, Hamza; Aichelin, Jörg; Cassing, Wolfgang; Bratkovskaya, Elena
2014-01-01
In this study we evaluate the dynamical collisional energy loss of heavy quarks, their interaction rate as well as the different transport coefficients (drag and diffusion coefficients, $\\hat{q}$, etc). We calculate these different quantities for i) perturbative partons (on-shell particles in the vacuum with fixed and running coupling) and ii) for dynamical quasi-particles (off-shell particles in the QGP medium at finite temperature $T$ with a running coupling in temperature as described by the dynamical quasi-particles model). We use the perturbative elastic $(q(g) Q \\rightarrow q (g) Q)$ cross section for the first case, and the Infrared Enhanced Hard Thermal Loop cross sections for the second. The results obtained in this work demonstrate the effects of a finite parton mass and width on the heavy quark transport properties and provide the basic ingredients for an explicit study of the microscopic dynamics of heavy flavors in the QGP - as formed in relativistic heavy-ion collisions - within transport approa...
Expanding plasmas and quasinormal modes of anti-de Sitter black holes
Friess, J J; Michalogiorgakis, G; Pufu, S S; Friess, Joshua J.; Gubser, Steven S.; Michalogiorgakis, Georgios; Pufu, Silviu S.
2007-01-01
We compute the gravitational quasinormal modes of the global AdS_5-Schwarzschild solution. We show how to use the holographic dual of these modes to describe a thermal plasma of finite extent expanding in a slightly anisotropic fashion. We compare these flows with the behavior of quark-gluon plasmas produced in relativistic heavy ion collisions by estimating the elliptic flow coefficient and the thermalization time.
Exploring Quarks, Gluons and the Higgs Boson
Johansson, K. Erik
2013-01-01
With real particle collision data available on the web, the amazing dynamics of the fundamental particles of the standard model can be explored in classrooms. Complementing the events from the ATLAS experiment with animations of the fundamental processes on the quark and gluon level makes it possible to better understand the invisible world of…
Exploring Quarks, Gluons and the Higgs Boson
Johansson, K. Erik
2013-01-01
With real particle collision data available on the web, the amazing dynamics of the fundamental particles of the standard model can be explored in classrooms. Complementing the events from the ATLAS experiment with animations of the fundamental processes on the quark and gluon level makes it possible to better understand the invisible world of…
Quark-gluon separation at the LHC
Rauco, Giorgia
2017-01-01
Studies focused on the discrimination between gluon- and quark-like jets at the LHC are presented. The results here discussed are obtained with proton collisions collected by the ATLAS experiment at 8 TeV and by the CMS experiment at 13 TeV.
Shear viscosities of photons in strongly coupled plasmas
Directory of Open Access Journals (Sweden)
Di-Lun Yang
2016-09-01
Full Text Available We investigate the shear viscosity of thermalized photons in the quark gluon plasma (QGP at weak coupling and N=4 super Yang–Mills plasma (SYMP at both strong and weak couplings. We find that the shear viscosity due to the photon–parton scattering up to the leading order of electromagnetic coupling is suppressed when the coupling of the QGP/SYMP is increased, which stems from the blue-shift of the thermal-photon spectrum at strong coupling. In addition, the shear viscosity rapidly increases near the deconfinement transition in a phenomenological model analogous to the QGP.
Hydrodynamization and transient modes of expanding plasma in kinetic theory
Heller, Michal P; Spalinski, Michal
2016-01-01
We study the transition to hydrodynamics in a weakly-coupled model of quark-gluon plasma given by kinetic theory in the relaxation time approximation. Our studies uncover qualitative similarities to the results on hydrodynamization in strongly coupled gauge theories. In particular, we demonstrate that the gradient expansion in this model has vanishing radius of convergence. The asymptotic character of the hydrodynamic gradient expansion is crucial for the recently discovered applicability of hydrodynamics at large gradients. Furthermore, the analysis of the resurgent properties of the series provides, quite remarkably, indication for the existence of a novel transient, damped oscillatory mode of expanding plasmas in kinetic theory.
Shear viscosities of photons in strongly coupled plasmas
Yang, Di-Lun; Müller, Berndt
2016-09-01
We investigate the shear viscosity of thermalized photons in the quark gluon plasma (QGP) at weak coupling and N = 4 super Yang-Mills plasma (SYMP) at both strong and weak couplings. We find that the shear viscosity due to the photon-parton scattering up to the leading order of electromagnetic coupling is suppressed when the coupling of the QGP/SYMP is increased, which stems from the blue-shift of the thermal-photon spectrum at strong coupling. In addition, the shear viscosity rapidly increases near the deconfinement transition in a phenomenological model analogous to the QGP.
Plasma Science and Applications at the Intel Science Fair: A Retrospective
Berry, Lee
2009-11-01
For the past five years, the Coalition for Plasma Science (CPS) has presented an award for a plasma project at the Intel International Science and Engineering Fair (ISEF). Eligible projects have ranged from grape-based plasma production in a microwave oven to observation of the effects of viscosity in a fluid model of quark-gluon plasma. Most projects have been aimed at applications, including fusion, thrusters, lighting, materials processing, and GPS improvements. However diagnostics (spectroscopy), technology (magnets), and theory (quark-gluon plasmas) have also been represented. All of the CPS award-winning projects so far have been based on experiments, with two awards going to women students and three to men. Since the award was initiated, both the number and quality of plasma projects has increased. The CPS expects this trend to continue, and looks forward to continuing its work with students who are excited about the possibilities of plasma. You too can share this excitement by judging at the 2010 fair in San Jose on May 11-12.
Scharenberg, R P; Hirsch, A S
2010-01-01
The Color String Percolation Model (CSPM) is used to determine the equation of state (EOS) of the QGP produced in central Au-Au collisions at $\\sqrt{s_{NN}}$ = 200 A GeV using STAR data at RHIC. When the initial density of interacting colored strings exceeds the 2D percolation threshold a cluster is formed, which defines the onset of color deconfinement. These interactions also produce fluctuations in the string tension which transforms the Schwinger particle (gluon) production mechanism into a maximum entropy thermal distribution. The single string tension is determined by identifying the known value of the universal hadron limiting temperature $T_{c}$ = 167.7 $\\pm$ 2.6 MeV with the CSPM percolation temperature at the critical threshold $\\xi_{c}$ =1.2. At mid-rapidity the initial Bjorken energy density and the initial temperature determine the number of degrees of freedom consistent with the formation of a $\\sim$ 2+1 flavor QGP. An analytic expression for the equation of state, the sound velocity $C_{s}^{2}(...
Dileptons from a Chemically Non-equilibrated Quark-Gluon Plasma%化学非平衡夸克-胶子等离子体中的双轻子产生
Institute of Scientific and Technical Information of China (English)
龙家丽; 贺泽君; 蒋维洲; 马余刚; 刘波
2004-01-01
研究了正在进行化学平衡的具有有限重子密度的夸克-胶子等离子体系统的演化和双轻子产生.结果发现由于夸克相的寿命随初始夸克化学势的增加而增加,以及其他一些因素,如较高的初始温度、较大的胶子密度和较大的胶子聚变和夸克湮没反应截面,导致热粲夸克对双轻子产生提供了占统治的贡献. 这个效应造成中等质量双轻子的重大增强.
Abelianization of QCD plasma instabilities
Arnold, Peter; Lenaghan, Jonathan
2004-12-01
QCD plasma instabilities appear to play an important role in the equilibration of quark-gluon plasmas in heavy-ion collisions in the theoretical limit of weak coupling (i.e. asymptotically high energy). It is important to understand what nonlinear physics eventually stops the exponential growth of unstable modes. It is already known that the initial growth of plasma instabilities in QCD closely parallels that in QED. However, once the unstable modes of the gauge fields grow large enough for non-Abelian interactions between them to become important, one might guess that the dynamics of QCD plasma instabilities and QED plasma instabilities become very different. In this paper, we give suggestive arguments that non-Abelian self-interactions between the unstable modes are ineffective at stopping instability growth, and that the growing non-Abelian gauge fields become approximately Abelian after a certain stage in their growth. This in turn suggests that understanding the development of QCD plasma instabilities in the nonlinear regime may have close parallels to similar processes in traditional plasma physics. We conjecture that the physics of collisionless plasma instabilities in SU(2) and SU(3) gauge theory becomes equivalent, respectively, to (i) traditional plasma physics, which is U(1) gauge theory, and (ii) plasma physics of U(1)×U(1) gauge theory.
Strong-coupling effects in a plasma of confining gluons
Florkowski, Wojciech; Su, Nan; Tywoniuk, Konrad
2015-01-01
The plasma consisting of confining gluons resulting from the Gribov quantization of the SU(3) Yang-Mills theory is studied using non-equilibrium fluid dynamical framework. Exploiting the Bjorken symmetry and using linear response theory a general analytic expressions for the bulk and shear viscosity coefficients are derived. It is found that the considered system exhibits a number of properties similar to the strongly-coupled theories, where the conformality is explicitly broken. In particular, it is shown that, in the large temperature limit, bulk to shear viscosity ratio, scales linearly with the difference $1/3 - c_s^2$, where $c_s$ is the speed of sound. Results obtained from the analysis are in line with the interpretation of the quark-gluon plasma as an almost perfect fluid.
Relativistic longitudinal non-Abelian oscillations in quark–antiquark plasma
Indian Academy of Sciences (India)
Vishnu M Bannur
2002-10-01
We study the relativistic version of the non-Abelian, longitudinal wave in quark–antiquark plasma reported earlier by Bhat et al [Phys. Rev. D39, 649 (1989)]. We have also relaxed various approximations they made in their analysis. Both the quark and antiquark dynamics are taken in our analysis. The non-linearity arising from non-Abelian ﬁeld as well as from plasma are included. Hence it is an exact longitudinal mode in relativistic quark–antiquark plasma, relevant to the study of quark gluon plasma. We ﬁnd that earlier results are reproduced for non-relativistic and low amplitude oscillations, but are modiﬁed for relativistic or large amplitude waves. Further more, the above results are based on just four ﬁrst-order equations for gauge invariant quantities derived from gauge covariant twelve ﬁrst-order equations.
Massive quark-gluon scattering amplitudes at tree level
Hall, Anthony
2008-01-01
Results for four-, five-, and six-parton tree amplitudes for massive quark-antiquark scattering with gluons are calculated using the recursion relations of Britto, Cachazo, Feng, and Witten. The required diagrams are generated using shifts of the momenta of a pair of massless legs to complex values. Checks verifying the calculations are described, and a simple formula for the shifted spinors of an internal gluon is presented.
Quark/gluon jet discrimination: a reproducible analysis using R
CERN. Geneva
2017-01-01
The power to discriminate between light-quark jets and gluon jets would have a huge impact on many searches for new physics at CERN and beyond. This talk will present a walk-through of the development of a prototype machine learning classifier for differentiating between quark and gluon jets at experiments like those at the Large Hadron Collider at CERN. A new fast feature selection method that combines information theory and graph analytics will be outlined. This method has found new variables that promise significant improvements in discrimination power. The prototype jet tagger is simple, interpretable, parsimonious, and computationally extremely cheap, and therefore might be suitable for use in trigger systems for real-time data processing. Nested stratified k-fold cross validation was used to generate robust estimates of model performance. The data analysis was performed entirely in the R statistical programming language, and is fully reproducible. The entire analysis workflow is data-driven, automated a...
Nuclear phenomena derived from quark-gluon strings
DEFF Research Database (Denmark)
Bohr, Henrik; Providencia, Constanca; Providencia, Joao da
2005-01-01
provided that the chiral fields are identified with the two-particle strings, which are natural in a QCD framework. Moreover, the model is able to reconcile qualitatively such aspects of hadronic physics as saturation density and binding energy of nuclear matter, surface density of finite nuclei, mass......, for the occurrence of the phases of nuclear matter. The model exhibits a quark deconfinement transition and chiral restoration, which are ingredients of QCD and give qualitatively correct numerics. The effective model is shown to be isomorphic to the Nambu-Jona-Lasinio model and exhibits the correct chirality...
Thermalization of mini-jets in a quark–gluon plasma
Energy Technology Data Exchange (ETDEWEB)
Iancu, Edmond, E-mail: edmond.iancu@cea.fr; Wu, Bin, E-mail: bin.wu.phys@gmail.com [Institut de Physique Théorique, CEA Saclay, CNRS UMR 3681, F-91191 Gif-sur-Yvette (France); Department of Physics, The Ohio State University, Columbus, OH 43210 (United States)
2016-12-15
We present the complete physical picture for the evolution of a high-energy jet propagating through a weakly-coupled quark-gluon plasma (QGP) by analytical and numerical investigation of thermalization of the soft components of the jet. Our results support the following physical picture: the leading particle emits a significant number of mini-jets which promptly evolve via multiple branching and thus degrade into a myriad of soft gluons, with energies of the order of the medium temperature T. Via elastic collisions with the medium constituents, these soft gluons relax to local thermal equilibrium with the plasma over a time scale which is considerably shorter than the typical lifetime of the mini-jet. The thermalized gluons form a tail which lags behind the hard components of the jet. Together with the background QGP, they behave hydrodynamically.
Adams, Allan; Schaefer, Thomas; Steinberg, Peter; Thomas, John E
2012-01-01
Strongly correlated quantum fluids are phases of matter that are intrinsically quantum mechanical, and that do not have a simple description in terms of weakly interacting quasi-particles. Two systems that have recently attracted a great deal of interest are the quark-gluon plasma, a plasma of strongly interacting quarks and gluons produced in relativistic heavy ion collisions, and ultracold atomic Fermi gases, very dilute clouds of atomic gases confined in optical or magnetic traps. These systems differ by more than 20 orders of magnitude in temperature, but they were shown to exhibit very similar hydrodynamic flow. In particular, both fluids exhibit a robustly low shear viscosity to entropy density ratio which is characteristic of quantum fluids described by holographic duality, a mapping from strongly correlated quantum field theories to weakly curved higher dimensional classical gravity. This review explores the connection between these fields, and it also serves as an introduction to the Focus Issue of N...
Parton energy loss and momentum broadening at NLO in high temperature QCD plasmas
Ghiglieri, Jacopo
2015-01-01
We present an overview of a perturbative-kinetic approach to jet propagation, energy loss, and momentum broadening in a high temperature quark-gluon plasma. The leading-order kinetic equations describe the interactions between energetic jet-particles and a non-abelian plasma, consisting of on-shell thermal excitations and soft gluonic fields. These interactions include 22 scatterings, collinear bremsstrahlung, and drag and momentum diffusion. We show how the contribution from the soft gluonic fields can be factorized into a set of Wilson line correlators on the light cone. We review recent field-theoretical developments, rooted in the causal properties of these correlators, which simplify the calculation of the appropriate Wilson lines in thermal field theory. With these simplifications lattice measurements of transverse momentum broadening have become possible, and the kinetic equations describing parton transport have been extended to next-to-leading order in the coupling g.
The Abelianization of QCD Plasma Instabilities
Arnold, P; Arnold, Peter; Lenaghan, Jonathan
2004-01-01
QCD plasma instabilities appear to play an important role in the equilibration of quark-gluon plasmas in heavy-ion collisions in the theoretical limit of weak coupling (i.e. asymptotically high energy). It is important to understand what non-linear physics eventually stops the exponential growth of unstable modes. It is already known that the initial growth of plasma instabilities in QCD closely parallels that in QED. However, once the unstable modes of the gauge-fields grow large enough for non-Abelian interactions between them to become important, one might guess that the dynamics of QCD plasma instabilities and QED plasma instabilities become very different. In this paper, we give suggestive arguments that non-Abelian self-interactions between the unstable modes are ineffective at stopping instability growth, and that the growing non-Abelian gauge fields become approximately Abelian after a certain stage in their growth. This in turn suggests that understanding the development of QCD plasma instabilities i...
Supersymmetric plasma systems and their nonsupersymmetric counterparts
Czajka, Alina
2016-01-01
In this thesis a systematic comparison of supersymmetric plasma systems and their nonsupersymmetric counterparts is presented. The work is motivated by the AdS/CFT correspondence and the main aim is to check how much the plasma governed by the N=4 super Yang-Mills theory resembles the quark-gluon plasma studied experimentally in relativistic heavy-ion collisions. The analysis is done in a weak coupling regime where perturbative methods are applicable. Since the Keldysh-Schwinger approach is used, not only equilibrium but also nonequilibrium plasmas, which are assumed to be ultrarelativistic, are under consideration. First, using the functional techniques we introduce Faddeev-Popov ghosts into the Keldysh-Schwinger formalism of nonAbelian gauge theories. Next the collective excitations of the N=1 SUSY QED plasma are considered and compared to those of the usual QED system. The analysis is repeated to confront with each other the plasmas governed by the N=4 super Yang-Mills and QCD theories. Finally, transport ...
A real-time lattice simulation of the thermalization of a gluon plasma: first results
Attems, Maximilian; Schäfer, Christian; Wagenbach, Björn; Zafeiropoulos, Savvas
2016-01-01
To achieve an understanding of the thermalization of a quark-gluon plasma, starting from QCD without using model assumptions, is a formidable task. We study the early stage dynamics of a relativistic heavy ion collision in the framework of real time simulations of classical Yang-Mills theory in a static box with the color glass condensate as initial condition. Our study generalizes a previous one by Fukushima and Gelis from SU(2) to the realistic case of SU(3). We calculate the chromo-electric and chromo-magnetic energy densities as well as the ratio of longitudinal and transverse pressure as a function of time as probes for thermalization. Our preliminary results on coarse lattices show the occurrence of Weibel instabilities prior to thermalization.
Hafez, M. G.; Talukder, M. R.; Sakthivel, R.
2016-05-01
The theoretical and numerical studies have been investigated on nonlinear propagation of weakly relativistic ion acoustic solitary waves in an unmagnetized plasma system consisting of nonextensive electrons, positrons and relativistic thermal ions. To study the characteristics of nonlinear propagation of the three-component plasma system, the reductive perturbation technique has been applied to derive the Korteweg-de Vries equation, which divulges the soliton-like solitary wave solution. The ansatz method is employed to carry out the integration of this equation. The effects of nonextensive electrons, positrons and relativistic thermal ions on phase velocity, amplitude and width of soliton and electrostatic nonlinear propagation of weakly relativistic ion acoustic solitary waves have been discussed taking different plasma parameters into consideration. The obtained results can be useful in understanding the features of small amplitude localized relativistic ion acoustic solitary waves in an unmagnetized three-component plasma system for hard thermal photon production with relativistic heavy ions collision in quark-gluon plasma as well as for astrophysical plasmas.
Nendaz, Fabien
The ALICE experiment at LHC will study from 2010 the quark-gluon plasma (QGP), phase of the matter in which quarks and gluons are deconfined. The work presented here was done within the ALICE collaboration, for preparing the analysis of the incoming experimental data. Besides a theoretical approach of the QGP and of the chiral symmetry, we develop three experimental aspects: the V0 sub-detector, the study of the low mass mesons and the deconvolution. First, we detail the measures of luminosity and multiplicity that can be done with the V0. We then develop the study of the dimuons in the muon spectometer. We concentrate on the low masses mesons: the rho, the omega and the phi. Finally, we present a method for improving the spectrometer data: the Richardson-Lucy deconvolution.
On the evolution of jet energy and opening angle in strongly coupled plasma
Energy Technology Data Exchange (ETDEWEB)
Chesler, Paul M. [Department of Physics, Harvard University,Cambridge MA 02138 (United States); Rajagopal, Krishna [Center for Theoretical Physics, MIT,Cambridge MA 02139 (United States)
2016-05-17
We calculate how the energy and the opening angle of jets in N=4 SYM theory evolve as they propagate through the strongly coupled plasma of that theory. We define the rate of energy loss dE{sub jet}/dx and the jet opening angle in a straightforward fashion directly in the gauge theory before calculating both holographically, in the dual gravitational description. In this way, we rederive the previously known result for dE{sub jet}/dx without the need to introduce a finite slab of plasma. We obtain a striking relationship between the initial opening angle of the jet, which is to say the opening angle that it would have had if it had found itself in vacuum instead of in plasma, and the thermalization distance of the jet. Via this relationship, we show that N=4 SYM jets with any initial energy that have the same initial opening angle and the same trajectory through the plasma experience the same fractional energy loss. We also provide an expansion that describes how the opening angle of the N=4 SYM jets increases slowly as they lose energy, over the fraction of their lifetime when their fractional energy loss is not yet large. We close by looking ahead toward potential qualitative lessons from our results for QCD jets produced in heavy collisions and propagating through quark-gluon plasma.
Strongly coupled non-Abelian plasmas in a magnetic field
Critelli, Renato
2016-01-01
In this dissertation we use the gauge/gravity duality approach to study the dynamics of strongly coupled non-Abelian plasmas. Ultimately, we want to understand the properties of the quark-gluon plasma (QGP), whose scientifc interest by the scientific community escalated exponentially after its discovery in the 2000's through the collision of ultrarelativistic heavy ions. One can enrich the dynamics of the QGP by adding an external field, such as the baryon chemical potential (needed to study the QCD phase diagram), or a magnetic field. In this dissertation, we choose to investigate the magnetic effects. Indeed, there are compelling evidences that strong magnetic fields of the order $eB\\sim 10 m_\\pi^2$ are created in the early stages of ultrarelativistic heavy ion collisions. The chosen observable to scan possible effects of the magnetic field on the QGP was the viscosity, due to the famous result $\\eta/s=1/4\\pi$ obtained via holography. In a first approach we use a caricature of the QGP, the $\\mathcal{N}=4$ s...
The CPS Plasma Award at the Intel Science and Engineering Fair
Berry, Lee
2012-10-01
For the past eight years, the Coalition for Plasma Science (CPS) has presented an award for a plasma project at the Intel International Science and Engineering Fair (ISEF). We reported on the first five years of this award at the 2009 DPP Symposium. Pulsed neutron-producing experiments are a recurring topic, with the efforts now turning to applications. The most recent award at the Pittsburgh ISEF this past May was given for analysis of data from Brookhaven's Relativistic Heavy Ion Collider. The effort had the goal of understanding the fluid properties of the quark-gluon plasma. All of the CPS award-winning projects so far have been based on experiments, with four awards going to women students and four to men. In 2009 we noted that the number and quality of projects was improving. Since then, as we we predicted (hoped for), that trend has continued. The CPS looks forward to continuing its work with students who are excited about the possibilities of plasma. You too can share this excitement by judging at the 2013 fair in Phoenix on May 12-17. Information may be obtained by emailing cps@plasmacoalition.org.
A Rotation/Magnetism Analogy for the Quark Plasma
McInnes, Brett
2016-01-01
In peripheral heavy ion collisions, the Quark-Gluon Plasma that may be formed often has a large angular momentum per unit energy. This angular momentum may take the form of (local) rotation. In many physical systems, rotation can have effects analogous to those produced by a magnetic field; thus, there is a risk that the effects of local rotation in the QGP might be mistaken for those of the large genuine magnetic fields which are also known to arise in these systems. Here we use the gauge-gravity duality to investigate this, and we find indeed that, with realistic parameter values, local rotation has effects on the QGP (at high values of the baryonic chemical potential) which are not only of the same kind as those produced by magnetic fields, but which can in fact be substantially larger. Furthermore, the combined effect of rotation and magnetism is to change the shape of the main quark matter phase transition line in an interesting way, reducing the magnitude of its curvature; again, local rotation contribu...
Anisotropic shear viscosity of a strongly coupled non-Abelian plasma from magnetic branes
Critelli, R; Zaniboni, M; Noronha, J
2014-01-01
Recent estimates for the electromagnetic fields produced in the early stages of non-central ultra-relativistic heavy ion collisions indicate the presence of magnetic fields $B\\sim \\mathcal{O}(0.1-15\\,m_\\pi^2)$, where $m_\\pi$ is the pion mass. It is then of special interest to study the effects of strong (Abelian) magnetic fields on the transport coefficients of strongly coupled non-Abelian plasmas, such as the quark-gluon plasma formed in heavy ion collisions. In this work we study the anisotropy in the shear viscosity induced by an external magnetic field in a strongly coupled $\\mathcal{N} = 4$ SYM plasma. Due to the spatial anisotropy created by the magnetic field, the most general viscosity tensor has 5 shear viscosity coefficients and 2 bulk viscosities. We use the holographic correspondence to evaluate two of the shear viscosities, $\\eta_{\\perp} \\equiv \\eta_{xyxy}$ (perpendicular to the magnetic field) and $\\eta_{\\parallel} \\equiv \\eta_{xzxz}=\\eta_{yzyz}$ (parallel to the field). When $B\
Energy Technology Data Exchange (ETDEWEB)
Scharenberg, R.P.; Hirsch, A.S.; Tincknell, M.L.
1992-09-15
An experiment to search for the production of quark{endash}gluon plasma in proton{endash}antiproton interactions is described with emphasis on 1992 results. Next, a search for critical phenomena using the EOS Time Projection Chamber is similarly described, including the results of 1992 test runs, nucleus{endash}nucleus collision simulations, and the extraction of critical indices from small percolation lattices. Analysis of results from experiments to detect the possible production of anomalous photons in the central rapidity region with transverse momentum between 5 and 50 MeV/c are discussed. Initial work on an experiment to study the high-density, high-temperature state of matter formed in collisions of heavy nuclei at relativistic energies, planned to begin in fall 1997, is related. Finally, work on a research and development project to investigate silicon avalanche diodes as time-of-flight detectors for nuclear and particle physics applications is reviewed. The principle is to detect the ionization of charged particles directly in the Si; feasibility has been demonstrated.
Energy Technology Data Exchange (ETDEWEB)
Scharenberg, R.P.; Hirsch, A.S.; Tincknell, M.L.
1992-09-15
An experiment to search for the production of quark[endash]gluon plasma in proton[endash]antiproton interactions is described with emphasis on 1992 results. Next, a search for critical phenomena using the EOS Time Projection Chamber is similarly described, including the results of 1992 test runs, nucleus[endash]nucleus collision simulations, and the extraction of critical indices from small percolation lattices. Analysis of results from experiments to detect the possible production of anomalous photons in the central rapidity region with transverse momentum between 5 and 50 MeV/c are discussed. Initial work on an experiment to study the high-density, high-temperature state of matter formed in collisions of heavy nuclei at relativistic energies, planned to begin in fall 1997, is related. Finally, work on a research and development project to investigate silicon avalanche diodes as time-of-flight detectors for nuclear and particle physics applications is reviewed. The principle is to detect the ionization of charged particles directly in the Si; feasibility has been demonstrated.
Adams, Allan; Carr, Lincoln D.; Schäfer, Thomas; Steinberg, Peter; Thomas, John E.
2012-11-01
Strongly correlated quantum fluids are phases of matter that are intrinsically quantum mechanical and that do not have a simple description in terms of weakly interacting quasiparticles. Two systems that have recently attracted a great deal of interest are the quark-gluon plasma, a plasma of strongly interacting quarks and gluons produced in relativistic heavy ion collisions, and ultracold atomic Fermi gases, very dilute clouds of atomic gases confined in optical or magnetic traps. These systems differ by 19 orders of magnitude in temperature, but were shown to exhibit very similar hydrodynamic flows. In particular, both fluids exhibit a robustly low shear viscosity to entropy density ratio, which is characteristic of quantum fluids described by holographic duality, a mapping from strongly correlated quantum field theories to weakly curved higher dimensional classical gravity. This review explores the connection between these fields, and also serves as an introduction to the focus issue of New Journal of Physics on ‘Strongly Correlated Quantum Fluids: From Ultracold Quantum Gases to Quantum Chromodynamic Plasmas’. The presentation is accessible to the general physics reader and includes discussions of the latest research developments in all three areas.
Axions and saxions from the primordial supersymmetric plasma and extra radiation signatures
Energy Technology Data Exchange (ETDEWEB)
Graf, Peter; Steffen, Frank Daniel, E-mail: graf@mpp.mpg.de, E-mail: steffen@mpp.mpg.de [Max-Planck-Institut für Physik, Föhringer Ring 6, D–80805 Munich (Germany)
2013-02-01
We calculate the rate for thermal production of axions and saxions via scattering of quarks, gluons, squarks, and gluinos in the primordial supersymmetric plasma. Systematic field theoretical methods such as hard thermal loop resummation are applied to obtain a finite result in a gauge-invariant way that is consistent to leading order in the strong gauge coupling. We calculate the thermally produced yield and the decoupling temperature for both axions and saxions. For the generic case in which saxion decays into axions are possible, the emitted axions can constitute extra radiation already prior to big bang nucleosynthesis and well thereafter. We update associated limits imposed by recent studies of the primordial helium-4 abundance and by precision cosmology of the cosmic microwave background and large scale structure. We show that the trend towards extra radiation seen in those studies can be explained by late decays of thermal saxions into axions and that upcoming Planck results will probe supersymmetric axion models with unprecedented sensitivity.
Quark masses from quark-gluon condensates in a modified perturbative QCD
Cabo-Montes de Oca, Alejandro
2003-01-01
In this note, it is argued that the mass matrix for the six quarks can be generated in first approximation by introducing fermion condensates on the same lines as was done before for gluons, within the modified perturbative expansion for QCD proposed in former works. Thus, the results point in the direction of the conjectured link of the approximate `Democratic' symmetry of the quark mass matrix and `gap' effects similar to the ones occuring in superconductivity. The condensates are introduced here non-dynamically and therefore the question of the possibility for their spontaneous generation remains open. However, possible ways out of the predicted lack of the `Democratic' symmetry of the condensates resulting from the spontaneous breaking of the flavour symmetry are suggested. They come from an analysis based on the Cornwall--Jackiw--Tomboulis (CJT) effective potential for composite operators
Quarks, gluons, and color are sufficient, but are they necessary II
Bartlett, David
2017-01-01
The 25th anniversary of the death of John Stewart Bell, was marked by lively discussion in Physics Today. This activity spurred me to consider the quark as one of Bell's ugly ``hidden variables'' which can be discarded. Here I extend comments on topics that are usually thought to be settled. These include CP-violation in KLong decay and ``quantum spookiness'' in B-decays. Apparently, the simple reaction e+ e- goes to ``anything + anything bar'' misses essential hadronic physics. The psi was indeed discovered by observing a sharp peak in the total cross section for e+e- at SLAC, but the J was found in the fragments from pp collisions at Brookhaven. Similarly, the parity of the D-meson was determined in a particle reconstruction by an LBL-SLAC group. They analyzed the Dalitz plot of the K pi pi in fragments at SPEAR and found ``Evidence for Parity Nonconservation in the Decays of the Narrow states near 1.87 GeV/c2. The authors did not mention quarks at all. Finally, the parity of the B-meson may be relevant to the exotic ``charmonium'' states observed in fragments at the B-factories. Unfortunately, the parity of the B cannot currently be determined independently of the quark model[PDG-2014, B+/-,top page 51].
Quark-gluon discrimination in the search for gluino pair production at the LHC
Bhattacherjee, Biplob; Nojiri, Mihoko M; Sakaki, Yasuhito; Webber, Bryan R
2016-01-01
We study the impact of including quark- and gluon-initiated jet discrimination in the search for strongly interacting supersymmetric particles at the LHC. Taking the example of gluino pair production, considerable improvement is observed in the LHC search reach on including the jet substructure observables to the standard kinematic variables within a multivariate analysis. In particular, quark and gluon jet separation has higher impact in the region of intermediate mass-gap between the gluino and the lightest neutralino, as the difference between the signal and the standard model background kinematic distributions is reduced in this region. We also compare the predictions from different Monte Carlo event generators to estimate the uncertainty originating from the modelling of the parton shower and hadronization processes.
Deep learning in color: towards automated quark/gluon jet discrimination
Komiske, Patrick T.; Metodiev, Eric M.; Schwartz, Matthew D.
2017-01-01
Artificial intelligence offers the potential to automate challenging data-processing tasks in collider physics. To establish its prospects, we explore to what extent deep learning with convolutional neural networks can discriminate quark and gluon jets better than observables designed by physicists. Our approach builds upon the paradigm that a jet can be treated as an image, with intensity given by the local calorimeter deposits. We supplement this construction by adding color to the images, with red, green and blue intensities given by the transverse momentum in charged particles, transverse momentum in neutral particles, and pixel-level charged particle counts. Overall, the deep networks match or outperform traditional jet variables. We also find that, while various simulations produce different quark and gluon jets, the neural networks are surprisingly insensitive to these differences, similar to traditional observables. This suggests that the networks can extract robust physical information from imperfect simulations.
Meson-baryon interaction in the quark-gluon exchange framework
Hadjimichef, D
1999-01-01
We extend the Fock-Tani formalism to include the meson-baryon interaction. The Fock-Tani formalism is a first principle method which allows the use of field theoretic methods for treating systems of composite particles. An application of this general result can be the $K^{+}N$ system which is now reconized as much more suitable system for the investigation of the short range nature of the hadronic repulsion.
Quantum field kinetics of QCD quark-gluon transport theory for light-cone dominated processes
Kinder-Geiger, Klaus
1996-01-01
A quantum kinetic formalism is developed to study the dynamical interplay of quantum and statistical-kinetic properties of non-equilibrium multi-parton systems produced in high-energy QCD processes. The approach provides the means to follow the quantum dynamics in both space-time and energy-momentum, starting from an arbitrary initial configuration of high-momentum quarks and gluons. Using a generalized functional integral representation and adopting the `closed-time-path' Green function techniques, a self-consistent set of equations of motions is obtained: a Ginzburg-Landau equation for a possible color background field, and Dyson-Schwinger equations for the 2-point functions of the gluon and quark fields. By exploiting the `two-scale nature' of light-cone dominated QCD processes, i.e. the separation between the quantum scale that specifies the range of short-distance quantum fluctuations, and the kinetic scale that characterizes the range of statistical binary inter- actions, the quantum-field equations of ...
Transition between nuclear and quark-gluon descriptions of hadrons and light nuclei.
Holt, R J; Gilman, R
2012-08-01
We provide a perspective on studies aimed at observing the transition between hadronic and quark-gluonic descriptions of reactions involving light nuclei. We begin by summarizing the results for relatively simple reactions such as the pion form factor and the neutral pion transition form factor as well as that for the nucleon and end with exclusive photoreactions in our simplest nuclei. A particular focus will be on reactions involving the deuteron. It is noted that a firm understanding of these issues is essential for unravelling important structure information from processes such as deeply virtual Compton scattering as well as deeply virtual meson production. The connection to exotic phenomena such as color transparency will be discussed. A number of outstanding challenges will require new experiments at modern facilities on the horizon as well as further theoretical developments.
Production of dileptons with intermediate masses in an expanding quark-gluon matter
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
A study of dilepton spectra, in intermediate mass region (IMR), from main background sources, quark phase, and secondary processes in hadronic phase on the basis of a relativistic hydrodynamic model has been carried out. The comparison between these results indicates that in this mass region the contribution from the background sources dominates, and due to the effect of the phase boundary on the evolution of the system the contribution from the quark phase becomes more important than that from secondary processes.
Hard probes (and soft ones) to test the quark-gluon soup
Preuss, Paul
2006-01-01
"We need the hardest probes of all to study the hot, dense state of matter that exists when two heavy nuclei like gold collide with enough energy to temporarily free the quarks and gluons in their constituent protons and neutrons." (3 pages)
Nucleon $g-2$ Structure Function at Large $x$ and Quark-Gluons Correlations
Energy Technology Data Exchange (ETDEWEB)
Zein-Eddine Meziani
2009-12-01
We discuss two recently carried out experiments at Jefferson Lab that measured with precision the spin structure function of the nucleon g2, aiming at the determination of the twist-3 matrix element known as d2 for both the proton and the neutron. This matrix element is related to the average Lorentz color force that a quark experiences just at the instant it is struck. It is also interpreted as a measurement of a linear combination of the electric and magnetic “color polarizability” in the nucleon.
Experimental Studies of Quark-Gluon Structure of Nucleons and Nuclei
Energy Technology Data Exchange (ETDEWEB)
Kyle, Gary
2004-12-17
The NMSU group has a lengthy history in the study of the nucleon structure and in particular its spin structure in terms of its fundamental constituents. This line of research is continuing in our current involvement in experiments at Brookhaven National Lab and the Thomas Jefferson National Accelerator Facility.
Quark-gluon double parton distributions in the light-front dressed quark model
Kasemets, Tomas
2016-01-01
We study parton distributions for two partons, a quark and a gluon, in the light-front dressed quark model, with focus on correlations between the two partons. The model calculation leads to sizable spin-spin and spin-kinematic correlations of interest for studies of double parton scattering (DPS) in high-energy collisions. In particular, we find that the transverse dependence of the double parton distributions (DPDs) does not factorize within the model. The results gives insight to the strengths of correlations in different kinematical regions, which can help in constructing input DPDs in cross section calculations.
Strangeness Production in 19.6 GeV Collisions at the Relativistic Heavy Ion Collider
2010-05-12
the universe. As of now, Quark-Giuon Plasma, QGP , is what scientists be lieve existed at the beginning. QGP is studied through the STAR Experiment at...Labs PHOBOS - One of the other experiments at Brookhaven National Labs QGP – Quark Gluon Plasma RHIC – Relativistic Heavy Ion Collider RICH – Ring...dynamics of the first three milliseconds of the universe. As of now, Quark-Gluon Plasma, QGP , is what scientists believe existed at the beginning. QGP is a
Cookson, C
2000-01-01
CERN has recreated on a small scale, the conditions that would have existed at the very beginning of the universe. The experiment has generated indirect evidence of the existence of quark-gluon plasma (1 page).
Signals of the QGP phase transition - a view from microscopic transport models
Bratkovskaya, E L
2007-01-01
In this contribution the results from various transport models on different observables - considered as possible signals of the phase transition from hadronic matter to the quark-gluon plasma (QGP) - are briefly reviewed.
Energy Technology Data Exchange (ETDEWEB)
Rafelski, Johann [CERN-PH/TH, Geneva 23 (Switzerland); The University of Arizona, Department of Physics, Tucson, Arizona (United States)
2015-09-15
Two phases of hot hadronic matter are described with emphasis put on their distinction. Here the role of strange particles as a characteristic observable of the quark-gluon plasma phase is particularly explored. (orig.)
Recent developments in QGP characterization
Energy Technology Data Exchange (ETDEWEB)
Jeon, Sangyong [Department of Physics, McGill University, Montréal (Canada)
2016-01-22
In recent years, great progress has been made in characterizing quark-gluon plasma (QGP) being created in ultra-relativistic heavy ion collisions. The article briefly reviews QGP characteristics found in hydrodynamic studies of the QGP collective flows.
Dumé, Belle
2003-01-01
"Physicists working at the Relativistic Heavy Ion Collider (RHIC) at the Brookhaven National Laboratory in the US say that they have come closer than ever before to creating a quark-gluon plasma" (0.5 page)
Has CERN made the stuff of the newborn universe?
Taubes, G
1997-01-01
Researchers at CERN report indications that they have recreated quark-gluon plasma in their Super Proton Synchrotron particle accelerator. The evidence involves the disappearance of of J/psi particles in lead-lead collisions.
Two views on the Bjorken scenario for ultra-relativistic heavy-ion collisions
Maire, Antonin
2011-01-01
The sketch describes the Bjorken scenario foreseen for the collision of ultra-relativistic heavy-ions, leading to the creation of strongly-interacting hot and dense deconfined matter, the so-called Quark-Gluon Plasma (QGP).
Rafelski, Johann
2016-11-01
These remarks open the one-day session "50 years of Hagedorn's Temperature and the Statistical Bootstrap Model". These developments set the path at CERN towards the discovery of Quark-Gluon Plasma in the year 2000.
The Chern-Simons diffusion rate in improved holographic QCD
National Research Council Canada - National Science Library
Gürsoy, U; Iatrakis, I; Kiritsis, E; Nitti, F; O’Bannon, A
2013-01-01
... ], with F the YM field strength. The Chern-Simons diffusion rate is a crucial ingredient for many CP-odd phenomena, including the chiral magnetic effect in the quark-gluon plasma. We compute Γ...
Clustering of Color Sources and the Equation of State of the QGP
Directory of Open Access Journals (Sweden)
Srivastava Brijesh K
2014-04-01
Full Text Available Possible phase transition of strongly interacting matter from hadron to a quark-gluon plasma state have in the past received considerable interest. It has been suggested that this problem might be treated by percolation theory. The clustering of color sources with percolation (CSPM is used to determine the equation of state (EOS and the transport coefficient of the Quark-Gluon Plasma (QGP produced in central A-A collisions at RHIC and LHC energies.
Clustering of Color Sources and the Equation of State of the QGP
Srivastava, Brijesh K.
2014-04-01
Possible phase transition of strongly interacting matter from hadron to a quark-gluon plasma state have in the past received considerable interest. It has been suggested that this problem might be treated by percolation theory. The clustering of color sources with percolation (CSPM) is used to determine the equation of state (EOS) and the transport coefficient of the Quark-Gluon Plasma (QGP) produced in central A-A collisions at RHIC and LHC energies.
Summary for theory and general session at the RHIC detector workshop
Energy Technology Data Exchange (ETDEWEB)
Kahana, S.
1985-01-01
The topics summarized include: cascade codes treating the components of nuclei as nucleons; a quark gluon cascade code; a treatment of shocks, detonation, and deflagration; putting finite density on the lattice as well as treating the phase transition at a finite critical temperature for vanishing density; theory for dilepton and photon signals and a treatment of the approach to equilibrium; the hydrodynamic evolution of the quark-gluon plasma; and QCD hydrodynamics. 13 refs., 7 figs.
Equation of state and viscosities from a gravity dual of the gluon plasma
Energy Technology Data Exchange (ETDEWEB)
Yaresko, Roman; Kaempfer, Burkhard [Helmholtz-Zentrum Dresden-Rossendorf (Germany); TU Dresden (Germany)
2014-07-01
Employing new precision data of the equation of state of the SU(3) Yang-Mills theory (gluon plasma) several dilaton potentials are adjusted in a holographic gravity-scalar set-up in the temperature range (1-10)T{sub c}. The relation between the potentials is investigated. The results suggest that the shape of the potentials in the region corresponding to the above temperature interval (parameterized by the horizon position of a black brane embedded in an asymptotically AdS Riemann space) is the same in each case and, in particular, independent of any assumed UV or IR asymptotics. We further observe that the holographically calculated bulk viscosity, based on the AdS/CFT duality, is determined entirely by the equation of state, i.e. is the same for different potentials which fit the lattice data equally well. We find the ratio of bulk viscosity to shear viscosity to be ζ/η ∼ πΔ v{sub s}{sup 2} for Δ v{sub s}{sup 2} < 0.2, where Δ v{sub s}{sup 2} ≡ 1/3 - v{sub s}{sup 2} is the non-conformality measure and v{sub s}{sup 2} is the squared velocity of sound. The inclusion of quark degrees of freedom is discussed to arrive at a dual description (equation of state and transport coefficients) of the quark-gluon plasma in the strong-coupling regime, as relevant for heavy-ion collisions at LHC and RHIC.
EVIDENCE FOR A NEW STATE OF MATTERQUARK-GLUON PLASMA AT CERN%欧洲核子研究中心发现新物质形态——夸克胶子等离子体存在的证据
Institute of Scientific and Technical Information of China (English)
庄鹏飞
2000-01-01
Important experimental results from CERN heavy ion collisions and their physical interpretation are reviewed.A hot and dense system is formed in the early stages of the collisions,and the energy density reaches the threshold to create quark-gluon plasma(QGP).The experimental phenomena like low-mass dilepton enhancement,J/Ψ suppression and strangeness enhancement can be explained through the formation of QGP.However,the current data are still not enough to prove the existence of QGP.%介绍和评述了欧洲核子研究中心(CERN)的相对论重离子碰撞的重要实验结果及其物理解释.碰撞初期形成了高温高密系统，能量密度达到了产生夸克胶子等离子体(QGP)的阈值.低质量双轻子增长、J/Ψ反常压低和奇异粒子增长等实验现象可以用形成了QGP来解释.但目前的实验还不足以证明已经产生了QGP.
sPHENIX: An Upgrade Concept from the PHENIX Collaboration
Aidala, C; Akiba, Y; Akiba, Y; Akimoto, R; Alexander, J; Aoki, K; Apadula, N; Asano, H; Asano, H; Atomssa, E T; Awes, T C; Azmoun, B; Babintsev, V; Bai, M; Bai, X; Bandara, N; Bannier, B; Barish, K N; Baron, O; Bassalleck, B; Bathe, S; Bathe, S; Baublis, V; Baumann, C; Baumgart, S; Bazilevsky, A; Beaumier, M; Belmont, R; Benjamin, G; Berdnikov, A; Berdnikov, Y; Bing, X; Black, D; Blackburn, J; Blau, D S; Bobrek, M; Bok, J; Bok, J; Boose, S; Boyle, K; Britton, C L; Brooks, M L; Bryslawskyj, J; Buesching, H; Bumazhnov, V; Butler, C; Butsyk, S; Campbell, S; Carollo, A; Chai, J -S; Chen, C -H; Chernichenko, S; Chi, C Y; Chiu, M; Choi, I J; Choi, J B; Choi, S; Chollet, S; Christiansen, P; Chujo, T; Cianciolo, V; Cole, B A; Cronin, N; Crossett, N; D'Orazio, L; Dairaku, S; Dairaku, S; Datta, A; Daugherity, M S; David, G; DeBlasio, K; Debraine, A; Dehmelt, K; Denisov, A; Deshpande, A; Deshpande, A; Desmond, E J; Dietzsch, O; Ding, L; Do, J H; Donadelli, M; Drapier, O; Drees, A; Drees, K A; Durham, J M; Durum, A; Eberle, L; Edwards, S; Efremenko, Y V; Engelmore, T; Enokizono, A; Esumi, S; Eyser, K O; Eyser, K O; Fadem, B; Fields, D E; Finger, M; Finger, M; Fleuret, F; Fokin, S L; Frantz, J E; Franz, A; Frawley, A D; Fukao, Y; Fukao, Y; Fusayasu, T; Gainey, K; Gal, C; Garg, P; Garishvili, A; Garishvili, I; Gastaldi, F; Ge, H; Giannotti, P; Giordarno, F; Glenn, A; Gong, X; Gonin, M; Goto, Y; Goto, Y; de Cassagnac, R Granier; Grau, N; Greene, S V; Perdekamp, M Grosse; Gu, Y; Gunji, T; Guragain, H; Haggerty, J S; Hahn, K I; Hamagaki, H; Han, S Y; Hanks, J; Hashimoto, K; Hashimoto, K; Hayano, R; Hayashi, S; He, X; Hemmick, T K; Hester, T; Hill, J C; Hoefferkamp, M; Hollis, R S; Homma, K; Hong, B; Hori, Y; Hoshino, T; Huang, J; Huang, S; Hutchins, J R; Ichihara, T; Ichihara, T; Ikeda, Y; Imai, K; Imazu, Y; Imrek, J; Inaba, M; Iordanova, A; Isenhower, D; Isinhue, A; Ivanischev, D; Ivanov, V; Jacak, B V; Jeon, S J; Jezghani, M; Jia, J; Jia, J; Jiang, X; Johnson, B M; Joo, K S; Jouan, D; Jumper, D S; Kamin, J; Kanda, S; Kang, B H; Kang, J H; Kang, J S; Kapustinsky, J; Karatsu, K; Karatsu, K; Kawall, D; Kazantsev, A V; Kehayias, H -J; Key, J A; Khachatryan, V; Khandai, P K; Khanzadeev, A; Kijima, K M; Kim, C; Kim, D H; Kim, D J; Kim, E -J; Kim, H J; Kim, K -B; Kim, Y -J; Kim, Y K; Kistenev, E; Klatsky, J; Kleinjan, D; Kline, P; Koblesky, T; Kochenda, L; Kofarago, M; Komatsu, Y; Komkov, B; Koster, J; Kotchetkov, D; Kotov, D; Kravtsov, P; Krizek, F; Kurita, K; Kuriyama, M; Kurosawa, M; Kurosawa, M; Kwon, Y; Lacey, R; Lai, Y S; Lajoie, J G; Lebedev, A; Lee, G H; Lee, J; Lee, K B; Lee, K S; Lee, S H; Lefferts, R; Leitch, M J; Leite, M A L; Leitgab, M; Lewis, B; Li, X; Lim, S H; Lipski, A; Liu, M X; Love, B; Lynch, D; Lynch, M; Maguire, C F; Makdisi, Y I; Makek, M; Makek, M; Manion, A; Manko, V I; Mannel, E; Maruyama, T; Masumoto, S; McCumber, M; McGaughey, P L; McGlinchey, D; McKay, R; McKinney, C; Meles, A; Mendoza, M; Menegasso, R; Meredith, B; Miake, Y; Mibe, T; Mignerey, A C; Milov, A; Mishra, D K; Mitchell, J T; Miyasaka, S; Miyasaka, S; Mizuno, S; Mohanty, A K; Morrison, D P; Moskowitz, M; Motschwiller, S; Moukhanova, T V; Murakami, T; Murakami, T; Murata, J; Murata, J; Mwai, A; Nagae, T; Nagamiya, S; Nagle, J L; Nagy, M I; Nagy, M I; Nakagawa, I; Nakagawa, I; Nakamiya, Y; Nakamura, K R; Nakamura, K R; Nakamura, T; Nakano, K; Nakano, K; Nattrass, C; Nederlof, A; Netrakanti, P K; Nihashi, M; Nihashi, M; Niida, T; Ninomiya, K; Ninomiya, K; Northacker, D; Nouicer, R; Nouicer, R; Novak, T; Novitzky, N; Nukariya, A; Nyanin, A S; O'Brien, E; Ogilvie, C A; Oide, H; Okada, K; Oskarsson, A; Ozawa, K; Ozawa, K; Pak, R; Pancake, C; Pantuev, V; Papavassiliou, V; Park, I H; Park, S; Park, S K; Pate, S F; Patel, L; Peng, J -C; Perepelitsa, D; Perera, G D N; Peressounko, D Yu; Perry, J; Petti, R; Pinkenburg, C; Pisani, R P; Popule, J; Purschke, M L; Qu, H; Radhakrishnan, S; Rak, J; Ravinovich, I; Read, K F; Read, K F; Reynolds, R; Riabov, V; Riabov, Y; Richardson, E; Riveli, N; Roach, D; Rolnick, S D; Rosati, M; Roschin, E; Ryu, M S; Safonov, A; Sahlmueller, B; Saito, N; Sakaguchi, T; Sako, H; Samsonov, V; Sano, M; Sarsour, M; Sato, S; Sawada, S; Schaefer, B; Sedgwick, K; Seele, J; Seidl, R; Seidl, R; Sekiguchi, Y; Sen, A; Seto, R; Sett, P; Shafto, E; Sharma, D; Shaver, A; Shein, I; Shibata, T -A; Shibata, T -A; Shigaki, K; Shimomura, M; Shoji, K; Shukla, P; Sicho, P; Sickles, A; Silva, C L; Silvermyr, D; Singh, B K; Singh, C P; Singh, V; Sippach, F W; Skolnik, M; Solano, S; Soldatov, A; Soltz, R A; Sondheim, W E; Sorensen, S P; Soumya, M; Sourikova, I V; Srivastava, P K; Stankus, P W; Steinberg, P; Stenlund, E; Stepanov, M; Ster, A; Stevens, L; Stoll, S P; Stone, M R; Sugitate, T; Sukhanov, A; Sun, J; Sziklai, J; Takagui, E M; Takahara, A; Taketani, A; Taketani, A; Tanaka, Y; Tanida, K; Tanida, K; Tannenbaum, M J; Tarafdar, S; Taranenko, A; Tate, A
2012-01-01
The PHENIX collaboration presents a concept for a major upgrade to the PHENIX detector at the Relativistic Heavy Ion Collider (RHIC). This upgrade, referred to as sPHENIX, brings exciting new capability to the RHIC program by opening new and important channels for experimental investigation and utilizing fully the luminosity of the recently upgraded RHIC facility. sPHENIX enables a compelling jet physics program that will address fundamental questions about the nature of the strongly coupled quark-gluon plasma discovered experimentally at RHIC to be a perfect fluid. The upgrade concept addresses specific questions whose answers are necessary to advance our understanding of the quark-gluon plasma: (1) How to reconcile the observed strongly coupled quark-gluon plasma with the asymptotically free theory of quarks and gluons? (2) What are the dynamical changes to the quark-gluon plasma in terms of quasiparticles and excitations as a function of temperature? (3) How sharp is the transition of the quark-gluon plasm...
Jets and charged particles in p+Pb and Pb+Pb collisions with the ATLAS Experiment
Spousta, Martin; The ATLAS collaboration
2016-01-01
Jets provide a powerful tool for probing the dynamics of the quark-gluon plasma created in Pb+Pb collisions at the LHC. The modification of high-pT jets as they propagate in the quark-gluon plasma provides insight on structure of the plasma at short-length scale. Such modifications have been observed in a variety of measurements of single jet, dijet, photon-jet and charged-particle fragmentation functions. Recent results of modifications of jets in proton-lead and Pb+Pb collisions will be presented.
Jet measurements in p+Pb and Pb+Pb with the ATLAS Experiment at the LHC
Santos, Helena; The ATLAS collaboration
2016-01-01
Jets provide a powerful tool for probing the dynamics of the quark-gluon plasma created in Pb+Pb collisions at the LHC. The modification of high-pT jets as they propagate in the quark-gluon plasma provides insight on structure of the plasma at short-length scale. Such modifications have been observed in a variety of measurements of single jet, dijet, photon-jet and charged-particle fragmentation functions. Recent results of modifications of jets in proton-lead and Pb+Pb collisions will be presented.
Energy Technology Data Exchange (ETDEWEB)
Guernane, R
2001-01-01
The ALICE experiment performed at the LHC will establish and study the phase transition from hadronic matter to a matter to a state of deconfined partons called Quark Gluon Plasma (QGP). The suppression of heavy flavour resonances (J{phi},{gamma}) is the most promising probe for diagnosing the formation and early stages of the QGP in ultrarelativistic heavy ion collisions. The complete spectrum of heavy quarkonia resonances, i.e. J/{phi}, {phi}', {gamma}, {gamma}' and {phi}' will be measured via their muonic decay in a forward spectrometer with a mass resolution sufficient to separate all states. It is composed of five tracking stations, each consisting of two Cathode Pad Chambers (CPC). In this work, we developed a prototype of CPC having the original feature of parallel charge read out from one segmented cathode. The geometry and operating parameters have been optimized for station 3. The expected multi-hit rate and multi-hit deconvolution have been evaluated with a complete detailed simulation and an efficient method to disentangle close hits has been proposed. The magnetic field effect on the intrinsic spatial resolution of the chambers has also been estimated. The simulated performance of the CPC's is confirmed by beam-test results obtained at CERN with prototypes. The measurement of dimuons is expected to be contaminated by beam-related background. The rate of beam-gas interactions is several orders of magnitude larger than the signal rate for p-p collisions which is the reference for further studies of p-A and A-A collisions. The ALICE Collaboration decided to equip the muon spectrometer with a level 0 trigger counter (V0) in order to validate the dimuon trigger signal in p-p mode. The various steps involved in designing the V0 scintillator hodoscope are presented in this thesis. (author)
Space-Time Geometry of Quark and Strange Quark Matter
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
We study quark and strange quark matter in the context of general relativity. For this purpose, we solve Einstein's field equations for quark and strange quark matter in spherical symmetric space-times. We analyze strange quark matter for the different equations of state (EOS) in the spherical symmetric space-times, thus we are able to obtain the space-time geometries of quark and strange quark matter. Also, we discuss die features of the obtained solutions. The obtained solutions are consistent with the results of Brookhaven Laboratory, i.e. the quark-gluon plasma has a vanishing shear (i.e. quark-gluon plasma is perfect).
Institute of Scientific and Technical Information of China (English)
2001-01-01
One of the aims to research relativistic heavy-ion collisions is to explore the probability of quark-gluon plasma phase transition from normal nuclear matter. Hadron and string cascade model (JPCIAE) ,based on the hypothesis without introducing the quark-gluon plasma (QGP), is employed to study the direct photon and π 0 transverse momentum distributions for central 208Pb+208Pb collisions at 158 AGeV/c; The theoretical results of transverse momentum distribution for both the direct photon and the π0 particle are lower than the data of WA98 experiment. Having considered the fact that the
Soft Gluon Radiation off Heavy Quarks beyond Eikonal Approximation
Directory of Open Access Journals (Sweden)
Trambak Bhattacharyya
2016-01-01
Full Text Available We calculate the soft gluon radiation spectrum off heavy quarks (HQs interacting with light quarks (LQs beyond small angle scattering (eikonality approximation and thus generalize the dead-cone formula of heavy quarks extensively used in the literatures of Quark-Gluon Plasma (QGP phenomenology to the large scattering angle regime which may be important in the energy loss of energetic heavy quarks in the deconfined Quark-Gluon Plasma medium. In the proper limits, we reproduce all the relevant existing formulae for the gluon radiation distribution off energetic quarks, heavy or light, used in the QGP phenomenology.
Introduction to high-energy heavy-ion collisions
Wong, Cheuk-Yin
1994-01-01
Written primarily for researchers and graduate students who are new in this emerging field, this book develops the necessary tools so that readers can follow the latest advances in this subject. Readers are first guided to examine the basic informations on nucleon-nucleon collisions and the use of the nucleus as an arena to study the interaction of one nucleon with another. A good survey of the relation between nucleon-nucleon and nucleus-nucleus collisions provides the proper comparison to study phenomena involving the more exotic quark-gluon plasma. Properties of the quark-gluon plasma and s
Photons from Quark and Hadron Phases in Au+Au Collisions
Institute of Scientific and Technical Information of China (English)
LONG Jia-Li; HE Ze-Jun; MA Yu-Gang; GUAN Na-Na
2008-01-01
Based on a relativistic hydrodynamic model describing the evolution of the chemically equilibrating quark-gluon plasma system with finite baryon density in a 3+l-dimensional spacetime, we compute photons from the quark phase, hadronic phase and initial non-thermal contributions. It is found that due to the effects of the initial quark chemical potential, chemical equilibration and rapid expansion of the system, the photon yield of the quark-gluon plasma is strongly suppressed, and photons from hadronic matter and initial non-thermal contributions almost reproduce experimental data.
Photons in a partonic transport approach
Energy Technology Data Exchange (ETDEWEB)
Greif, Moritz; Senzel, Florian; Greiner, Carsten [Goethe Universitaet Frankfurt, Max-von-Laue-Str. 1 60438 Frankfurt am Main (Germany)
2015-07-01
Partonic transport approaches have proved to be valuable tools in describing the quark-gluon plasma, created in heavy-ion collisions. In this work, first steps towards a dynamical understanding of photonproduction in expanding heavy-ion collisions are presented. Several photon production processes are included in the partonic cascade BAMPS (Boltzmann Approach to Multi-Parton Scatterings). BAMPS provides a microscopic tool to study expanding fireballs, employing a stochastic method to solve the relativistic 3+1d Boltzmann equation. Subsequently, photon spectra can be investigated, and in particular, the influence of the quark-gluon plasma phase for the elliptic flow of photons is studied.
Sadeghi, Jafar
2012-01-01
In this review article we consider a special case of D=5, $\\mathcal{N}=2$ supergravity called the STU model. We apply the gauge/gravity correspondence to the STU model to gain insight into properties of the quark-gluon plasma. Given that the quark-gluon plasma is in reality described by QCD, therefore we call our study STU/QCD correspondence. First, we investigate the thermodynamics and hydrodynamics of the STU background. Then we use dual picture of the theory, which is type IIB string theory, to obtain the drag force and jet-quenching parameter of an external probe quark.
Charge fluctuations in a final state with QGP
Fialkowski, K.; Wit, R. de
2001-01-01
Charge fluctuations as a possible signal of quark - gluon plasma (QGP) were recently suggested. A short summary of comments presented on this subject is given and supplemented by a discussion of the coexistence of pions produced "directly" and through a QGP phase. Such a coexistence may obscure the expected plasma signal similarly to the effects considered in the comments mentioned above.
J/ψ Dissociation in QGP via Multi-gluon Absorption
Institute of Scientific and Technical Information of China (English)
DING Yi-Bing; LI Xue-Qian; ZHANG Feng
2003-01-01
We propose that the suppression of J/ψ production in relativistic heavy ion collisions may be explained by that J/ψ dissociates via absorbing multi-gluons in the environment of quark-gluon-plasma (QGP) where abundance of gluons is expected.
J／Φ Dissociation in QGP via Multi-gluon Absorption
Institute of Scientific and Technical Information of China (English)
DINGYi-Bing; LIXue-Qian; ZHANGFeng
2003-01-01
We propose that the suppression of J/Φ production in relativistic heavy ion collisions may be explained by that J/Φ dissociates via absorbing multi-gluons in the environment of quark-gluon-plasma (QGP) where abundance of gluons is expected.
Recent relativistic heavy ion collider results on photon, dilepton and heavy quark
Indian Academy of Sciences (India)
Frédéric Fleuret
2009-01-01
We present here a review of the recent results obtained by the RHIC experiments in the framework of QCD under extreme conditions of high temperature or large baryon density, the so-called quark gluon plasma. We focus on a specific category of observables: the electromagnetic probes which cover a large spectrum of experimental studies.
Dynamical fermions in lattice quantum chromodynamics
Energy Technology Data Exchange (ETDEWEB)
Szabo, Kalman
2007-07-01
The thesis presentS results in Quantum Chromo Dynamics (QCD) with dynamical lattice fermions. The topological susceptibilty in QCD is determined, the calculations are carried out with dynamical overlap fermions. The most important properties of the quark-gluon plasma phase of QCD are studied, for which dynamical staggered fermions are used. (orig.)
Directory of Open Access Journals (Sweden)
Rafelski Johann
2016-01-01
Full Text Available These remarks open the one-day session “50 years of Hagedorn’s Temperature and the Statistical Bootstrap Model”. These developments set the path at CERN towards the discovery of Quark-Gluon Plasma in the year 2000.
't Hooft, Gerardus; Llewellyn Smith, Christopher Hubert; Brüning, Oliver Sim; Collier, Paul; Stapnes, Steinar; Ellis, Jonathan Richard; Braun-Munzinger, Peter; Stachel, Johanna; Lederman, Leon Max
2007-01-01
Several articles about the LHC: The Making of the standard model; high-energy colliders and the rise of the standard model; How the LHC came to be; Building a behemoth; Detector challenges at the LHC; Beyond the standard model with the LHC; The quest for the quark-gluon plasma; The God particle et al. (42 pages
Collective perspective on advances in Dyson-Schwinger Equation QCD
Bashir, Adnan; Cloet, Ian C; El-Bennich, Bruno; Liu, Yu-xin; Roberts, Craig D; Tandy, Peter C
2012-01-01
We survey contemporary studies of hadrons and strongly interacting quarks using QCD's Dyson-Schwinger equations, addressing: aspects of confinement and dynamical chiral symmetry breaking; the hadron spectrum; hadron elastic and transition form factors, from small- to large-Q^2; parton distribution functions; the physics of hadrons containing one or more heavy quarks; and properties of the quark gluon plasma.
Deconfinement phase transition in a finite volume in the presence of massive particles
Energy Technology Data Exchange (ETDEWEB)
Ait El Djoudi, A.; Ghenam, L. [Laboratoire de Physique des Particules et Physique Statistique, Ecole Normale Superieure - Kouba, B.P. 92, 16050, Vieux Kouba, Algiers (Algeria)
2012-06-27
We study the QCD deconfinement phase transition from a hadronic gas to a Quark-Gluon Plasma, in the presence of massive particles. Especially, the influence of some parameters as the finite volume, finite mass, flavors number N{sub f} on the transition point and on the order of the transition is investigated.
The Nonlinear Spatial Damping Rate in QGP
Jiarong, L
1998-01-01
The derivative expansion method has been used to solve the semiclassical kinetic equations of quark-gluon plasma (QGP). The nonlinear spatial damping rate, the imaginary part of the wave vector, for the longitudinal secondary color waves in the long wavelength limit has been calculated numerically.
Xin, W; Xin, Wang; Jiarong, Li
2000-01-01
Within the real-time formalism (RTF) of thermal field theory,we apply the hard thermal loop (HTL) resummation technique to calculating effective two-loop thermodynamic potential in quark-gluon plasma (QGP) and its renormalization. The result with collective effects is obtained, which is valid for an arbitrary number of quark flavors with masses.
The quarkonium saga in heavy ion collisions
Tserruya, Itzhak
2013-01-01
J/psi suppression was proposed more than 25 years ago as an unambiguous signature for the formation of the Quark Gluon Plasma in relativistic heavy ion collisions. After intensive efforts, both experimental and theoretical, the quarkonium saga remains exciting, producing surprising results and not fully understood. This talk focuses on recent results on quarkonium production at RHIC and the LHC.
BRIEF REPORT: The colour relaxation equation
Xiaofei, Zhang; Jiarong, Li
1996-03-01
Colour diffusion in quark - gluon plasma (QGP) is investigated from the transport equations of QGP. The pure non-Abelian collision term describing the colour diffusion in QGP is obtained, the expression for colour relaxation time is derived and the physical picture of the colour diffusion in QGP is shown.
Heavy Quarks and Heavy Quarkonia as Tests of Thermalization
Nagle, J L
2006-01-01
We present here a brief summary of new results on heavy quarks and heavy quarkonia from the PHENIX experiment as presented at the "Quark Gluon Plasma Thermalization" Workshop in Vienna, Austria in August 2005, directly following the International Quark Matter Conference in Hungary.
Two problems in thermal field theory
Indian Academy of Sciences (India)
François Gelis
2000-07-01
In this talk, I review recent progress made in two areas of thermal ﬁeld theory. In particular, I discuss various approaches for the calculation of the quark gluon plasma thermodynamical properties, and the problem of its photon production rate.
Inhomogeneous Thermalization in Strongly Coupled Field Theories
Balasubramanian, V.; Bernamonti, A.; de Boer, J.; Carps, B.; Franti, L.; Galli, F.; Keski-Vakkuri, E.; Müller, B.; Schäfer, A.
2013-01-01
To describe theoretically the creation and evolution of the quark-gluon plasma, one typically employs three ingredients: a model for the initial state, nonhydrodynamic early time evolution, and hydrodynamics. In this Letter we study the nonhydrodynamic early time evolution using the AdS/CFT
Anisotropic Flow and flow fluctuations at the Large Hadron Collider
Zhou, Y.
2016-01-01
One of the fundamental questions in the phenomenology of Quantum Chromodynamics (QCD) is what the properties of matter are at the extreme densities and temperatures where quarks and gluons are in a new state of matter, the so-called Quark Gluon Plasma (QGP). Collisions of high-energy heavy-ions at t
Two-particle azimuthal correlation in d+Au and p+p collision at sqrt{s_NN}=200 GeV in STAR
Benedosso, F.
2008-01-01
The goal of high--energy heavy--ion physics is the full characterization of the quark--gluon plasma (QGP), which is a phase of strongly interacting matter where quarks and gluons are no longer confined in the nucleons and can move freely over longer distances. Such a phase probably existed shortly a
Hadronic resonance production in d+Au collisions at √sNN = 200 GeV at RHIC
van Leeuwen, M.; Abelev, B.I.; Bai, Y.; Benedosso, F.; Botje, M.A.J.; Braidot, E; Mischke, A.; Peitzmann, T.; Russcher, M.J.; Snellings, R.J.M.
2008-01-01
Quantum chromodynamics (QCD) predicts that hadronic matter at high temperatures and/or high densities undergoes a phase transition to a system of deconfined partonic matter, the Quark Gluon Plasma (QGP) [1]. Matter under such extreme conditions can be studied in the laboratory by colliding nuclei at
Heavy-Ion Physics in a Nutshell
Directory of Open Access Journals (Sweden)
Hirano Tetsufumi
2013-05-01
Full Text Available The physics of quark gluon plasma (QGP and heavy ion collisions at the collider energies is briefly reviewed. We first discuss about the discovery of a nearly perfect fluidity of the QGP. We also highlights recent topics on responses of the QGP to initial deformation and propagation of a jet.
A Colored Particle Acceleration by Fluctuations in QGP
Xiaoping, Zheng; Jiarong, Li
1997-01-01
We discuss the energy variation of a parton passing through a quark-gluon plasma(QGP) taking into account nonlinear polarization effect. We find the parton can be accelerated by fluctuations in QGP, which gives us a new physical insight about the response of QGP to such external the current.
Has matter's mother paid a call?
Weiss, P
2003-01-01
"..Stunning results .. are prompting a growing chorus of physicists to say that it's time to declare success in a decades-long quest to make quark-gluon plasma - an extremely hot, dense soup of matter that contains loose fundamental particles known as quarks and gluons" (1 page).
Production of Direct Photons in Lead-Lead Collisions
Pijll, E.C. van der
2007-01-01
This thesis discusses one of the probes of a Quark Gluon Plasma (QGP): direct photon emission. The QGP is a state of matter that is hypothesized to exist at high baryon densities and high temperature. These circumstances are only available for experiments in heavy-ion collisions, and even there the
Path length dependence of jet quenching measured with ALICE at the LHC
Bertens, R.A.
2016-01-01
Jets are used to probe the quark-gluon plasma (QGP) that is created in heavy-ion collisions, by using the fact that medium-induced parton energy loss from elastic and radiative interactions between partons and the QGP lead to a modification of the measured jet spectrum. The dependence of the energy
Heavy-flavour meson production at RHIC
Mischke, A.
2010-01-01
Collisions of heavy atomic nuclei at very high beam energies allow to create and study hot QCD matter under laboratory-controlled conditions. Measurements at the SPS and RHIC facilities have yielded compelling evidence for the formation of this novel state of matter, the so-called Quark-Gluon Plasma
Modelling and measurement of jet quenching in relativistic heavy-ion collisions at the LHC
Verweij, M.
2013-01-01
In relativistic collisions between nuclei, the creation of a strongly interacting medium, called the Quark Gluon Plasma (QGP), is expected. It is expected that such a medium also existed in the early universe just after the Big Bang. The phase transition of interest is where the dense medium of free
Energy Density and Production Ratios of Baryon from QGP with Diquarks
Institute of Scientific and Technical Information of China (English)
MA Zhong-Biao; GAO Chong-Shou
2005-01-01
@@ At a very high temperature, the quark matter is a hot and dense matter under the colour deconfinement condition,and quarks can coalescent diquarks. Energy density of this system is figured out. A way to calculate baryon ratios produced from quark gluon plasma with diquarks in relativistic heavy ion collisions is presented.
Jet-like heavy-flavour particle correlations in proton-proton and lead-lead collisions in ALICE
Thomas, D.
2014-01-01
Ultra-relativistic heavy ion collisions facilitate the creation of high temperature and pressure that is sufficient to produce the Quark Gluon Plasma (QGP), which is a deconfined state of matter where quarks and gluons interact with each other. At the Large Hadron Collider (LHC), lead ions are accel
Pseudorapidity Dependence of Anisotropic Azimuthal Flow with the ALICE Detector
DEFF Research Database (Denmark)
Hansen, Alexander Colliander
In ultra-relativistic heavy-ion collisions a new state of matter known as the strongly interacting quark-gluon plasma (sQGP) is produced. A key observable in the study of the sQGP is anisotropic azimuthal ow. The anisotropies are described by ow harmonics, vn. In this thesis, bias arising from non...
Meson Screening Masses in Thermal QCD
Directory of Open Access Journals (Sweden)
Czerski Piotr
2012-12-01
Full Text Available The quark-gluon plasma (QGP excitations, corresponding to the scalar and pseudoscalar meson quantum numbers, for different temperatures are calculated. Analysis is performed in the Hard Thermal Loop (HTL Approximation and leads to a better understanding of the excitations of QGP in the deconfined phase and is also of relevance for lattice studies.
Temperature dependence of bag pressure from quasiparticle model
Prasad, N.; Singh, C. P.
2001-03-01
A quasiparticle model with effective thermal gluon and quark masses is used to derive a temperature /T- and baryon chemical potential /μ-dependent bag constant /B(μ,T). Consequences of such a bag constant are obtained on the equation of state (EOS) for a deconfined quark-gluon plasma (QGP).
Calivà, A.|info:eu-repo/dai/nl/411885812
2017-01-01
In ordinary matter, quarks and gluons are confined inside hadrons by the strong interaction. At extreme conditions of temperature and energy density, a new state of matter is formed, called quark-gluon plasma (QGP). This is made of deconfined quasi-free quarks and gluons. Based on the current
(Nuclear theory: Annual report)
Energy Technology Data Exchange (ETDEWEB)
Iachello, F.; Alhassid, Y.; Kusnezov, D.
1991-01-01
This report discusses topics on : nuclear structure models; algebraic models of hadronic structure; nuclear reactions; hot rotating nuclei; chaos in nuclei; signatures of the quark-gluon plasma; hadronic spectroscopy; octupole collectivity in nuclei; finite-temperature methods for the many-body problem; and classical limit of algebraic hamiltonians. (LSP)
[Nuclear theory: Annual report
Energy Technology Data Exchange (ETDEWEB)
Iachello, F.; Alhassid, Y.; Kusnezov, D.
1991-12-31
This report discusses topics on : nuclear structure models; algebraic models of hadronic structure; nuclear reactions; hot rotating nuclei; chaos in nuclei; signatures of the quark-gluon plasma; hadronic spectroscopy; octupole collectivity in nuclei; finite-temperature methods for the many-body problem; and classical limit of algebraic hamiltonians. (LSP)
Lambda Polarization in Lead-Lead Collisions
Schillings, Eelco
2003-01-01
In this thesis the production and polarization of Lambda particles produced in Pb-Pb collisions at a beam energy of 158 GeV/c per nucleon are studied. In these collisions nuclear matter is compressed and heated and under these conditions it is possible that a quark-gluon plasma (QGP) is created. In
Spatial anisotropy： a method to study anisotropic flow in heavy ion collisions
Institute of Scientific and Technical Information of China (English)
CUI Xiang-Li; LU Yan; WANG Xiao-Lian; PENG Ru
2011-01-01
We introduce a method to study anisotropic flow parameter v n as a collective probe to Quark Gluon Plasma in relativistic heavy ion collisions. The emphasis is put on the use of the Fourier expansion of initial spatial azimuthal distributions of participa
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
A study of Mach shocks generated by fast partonic jets propagating through the quark-gluon plasma (QGP) is reviewed briefly. We predict a significant deformation of Mach shocks in central Au+Au collisions at RHIC and LHC energies compared to those created by a jet propagation through a static medium.Moreover, a new hydrodynamical study of jet energy loss is presented.
Direct photon measurement in proton-proton and deuteron-gold collisions
Russcher, M.J.
2008-01-01
The primary goal of heavy ion physics is the study of the Quark Gluon Plasma (QGP). In this exotic state of matter, the quarks and gluons, which make up ordinary hadronic matter, decouple and behave as free particles. The QGP exists at extremely high temperatures and baryon densities, for example, i
RELATIVISTIC HEAVY ION PHYSICS: A THEORETICAL OVERVIEW.
Energy Technology Data Exchange (ETDEWEB)
KHARZEEV,D.
2004-03-28
This is a mini-review of recent theoretical work in the field of relativistic heavy ion physics. The following topics are discussed initial conditions and the Color Glass Condensate; approach to thermalization and the hydrodynamic evolution; hard probes and the properties of the Quark-Gluon Plasma. Some of the unsolved problems and potentially promising directions for future research are listed as well.
1996-01-01
This is an image of an actual lead ion collision taken from tracking detectors on the NA49 experiment, part of the heavy ion project at CERN. These collisions produce a very complicated array of hadrons as the heavy ions break up. It is hoped that one of these collisions will eventually create a new state of matter known as quark-gluon plasma.
2003-01-01
Fitted with new state-of-the-art silicon detectors, NA60 is prepared to study the phase transition from confined hadronic matter to a deconfined (free) quark-gluon plasma, a state of matter which probably existed an instant after the Big Bang.
Energy Technology Data Exchange (ETDEWEB)
Chapman, S.
1992-11-01
The goal in this thesis is thus twofold: The first is to investigate the feasibility of using heavy ion collisions to create conditions in the laboratory which are ripe for the formation of a quark-gluon plasma. The second is to develop a technique for studying some of the many non-perturbative features of this novel phase of matter.
D-meson production in p-Pb collisions at root S-NN=5.02 TeV and in pp collisions at root S=7 TeV
Adam, J.; Adamova, D.; Aggarwal, M. M.; Rinella, G. Aglieri; Agnello, M.; Agrawal, N.; Ahammed, Z.; Ahn, S. U.; Aiola, S.; Akindinov, A.; Alam, S. N.; Albuquerque, D. S. D.; Aleksandrov, D.; Alessandro, B.; Alexandre, D.; Molina, R. Alfaro; Alici, A.; Alkin, A.; Alme, J.; Alt, T.; Altinpinar, S.; Altsybeev, I.; Prado, C. Alves Garcia; Andrei, C.; Andronic, A.; Anguelov, V.; Anticic, T.; Antinori, F.; Antonioli, P.; Aphecetche, L.; Appelshaeuser, H.; Arcelli, S.; Arnaldi, R.; Arnold, O. W.; Arsene, I. C.; Arslandok, M.; Audurier, B.; Augustinus, A.; Averbeck, R.; Azmi, M. D.; Badala, A.; Baek, Y. W.; Bagnasco, S.; Bailhache, R.; Bala, R.; Balasubramanian, S.; Baldisseri, A.; Baral, R. C.; Barbano, A. M.; Barbera, R.; Barile, F.; Barnafoldi, G. G.; Barnby, L. S.; Barret, V.; Bartalini, P.; Barth, K.; Bartke, J.; Bartsch, E.; Basile, M.; Bastid, N.; Bathen, B.; Batigne, G.; Camejo, A. Batista; Batyunya, B.; Batzing, P. C.; Bearden, I. G.; Beck, H.; Bedda, C.; Behera, N. K.; Belikov, I.; Bellini, F.; Bello Martinez, H.; Bellwied, R.; Belmont, R.; Belmont-Moreno, E.; Beltran, L. G. E.; Belyaev, V.; Bencedi, G.; Beole, S.; Berceanu, I.; Bercuci, A.; Berdnikov, Y.; Berenyi, D.; Bertens, R. A.; Berzano, D.; Betev, L.; Bhasin, A.; Bhat, I. R.; Bhati, A. K.; Bhattacharjee, B.; Bhom, J.; Bianchi, L.; Bianchi, N.; Bianchin, C.; Bielcik, J.; Bielcikova, J.; Bilandzic, A.; Biro, G.; Biswas, R.; Biswas, S.; Blair, J. T.; Blau, D.; Blume, C.; Bock, F.; Bogdanov, A.; Boggild, H.; Boldizsar, L.; Bombara, M.; Bonora, M.; Book, J.; Borel, H.; Borissov, A.; Borri, M.; Bossu, F.; Botta, E.; Bourjau, C.; Braun-Munzinger, P.; Bregant, M.; Breitner, T.; Broker, T. A.; Browning, T. A.; Broz, M.; Brucken, E. J.; Bruna, E.; Bruno, G. E.; Budnikov, D.; Buesching, H.; Bufalino, S.; Buncic, P.; Busch, O.; Buthelezi, Z.; Butt, J. B.; Buxton, J. T.; Cabala, J.; Caffarri, D.; Cai, X.; Caines, H.; Diaz, L. Calero; Caliva, A.; Calvo Villar, E.; Camerini, P.; Carena, F.; Carena, W.; Carnesecchi, F.; Castellanos, J. Castillo; Castro, A. J.; Casula, E. A. R.; Ceballos Sanchez, C.; Cepila, J.; Cerello, P.; Cerkala, J.; Chang, B.; Chapeland, S.; Chartier, M.; Charvet, J. L.; Chattopadhyay, S.; Chattopadhyay, S.; Chauvin, A.; Chelnokov, V.; Cherney, M.; Cheshkov, C.; Cheynis, B.; Barroso, V. Chibante; Chinellato, D. D.; Cho, S.; Chochula, P.; Choi, K.; Choudhury, S.; Christakoglou, P.; Christensen, C. H.; Christiansen, P.; Chujo, T.; Cicalo, C.; Cifarelli, L.; Cindolo, F.; Cleymans, J.; Colamaria, F.; Colella, D.; Collu, A.; Colocci, M.; Balbastre, G. Conesa; del Valle, Z. Conesa; Connors, M. E.; Contreras, J. G.; Cormier, T. M.; Morales, Y. Corrales; Cortes Maldonado, I.; Cortese, P.; Cosentino, M. R.; Costa, F.; Crkovska, J.; Crochet, P.; Albino, R. Cruz; Cuautle, E.; Cunqueiro, L.; Dahms, T.; Dainese, A.; Danisch, M. C.; Danu, A.; Das, I.; Das, S.; Dash, A.; Dash, S.; De, S.; De Caro, A.; de Cataldo, G.; de Conti, C.; de Cuveland, J.; De Falco, A.; De Gruttola, D.; De Marco, N.; De Pasquale, S.; De Souza, R. D.; Deisting, A.; Deloff, A.; Denes, E.; Deplano, C.; Dhankher, P.; Di Bari, D.; Di Mauro, A.; Di Nezza, P.; Di Ruzza, B.; Corchero, M. A. Diaz; Dietel, T.; Dillenseger, P.; Divia, R.; Djuvsland, O.; Dobrin, A.; Gimenez, D. Domenicis; Doenigus, B.; Dordic, O.; Drozhzhova, T.; Dubey, A. K.; Ducroux, L.; Dupieux, P.; Ehlers, R. J.; Elia, D.; Endress, E.; Engel, H.; Epple, E.; Erazmus, B.; Erdemir, I.; Erhardt, F.; Espagnon, B.; Estienne, M.; Esumi, S.; Eum, J.; Evans, D.; Evdokimov, S.; Eyyubova, G.; Fabbietti, L.; Fabris, D.; Faivre, J.; Fantoni, A.; Fasel, M.; Feldkamp, L.; Feliciello, A.; Feofilov, G.; Ferencei, J.; Fernandez Tellez, A.; Ferreiro, E. G.; Ferretti, A.; Festanti, A.; Feuillard, V. J. G.; Figiel, J.; Figueredo, M. A. S.; Filchagin, S.; Finogeev, D.; Fionda, F. M.; Fiore, E. M.; Fleck, M. G.; Floris, M.; Foertsch, S.; Foka, P.; Fokin, S.; Fragiacomo, E.; Francescon, A.; Francisco, A.; Frankenfeld, U.; Fronze, G. G.; Fuchs, U.; Furget, C.; Furs, A.; Girard, M. Fusco; Gaardhoje, J. J.; Gagliardi, M.; Gago, A. M.; Gajdosova, K.; Gallio, M.; Galvan, C. D.; Gangadharan, D. R.; Ganoti, P.; Gao, C.; Garabatos, C.; Garcia-Solis, E.; Gargiulo, C.; Gasik, P.; Gauger, E. F.; Germain, M.; Gheata, M.; Gianotti, P.; Giubellino, P.; Giubilato, P.; Gladysz-Dziadus, E.; Glaessel, P.; Coral, D. M. Gomez; Ramirez, A. Gomez; Gonzalez, A. S.; Gonzalez, V.; Gonzalez-Zamora, P.; Gorbunov, S.; Gorlich, L.; Gotovac, S.; Grabski, V.; Grachov, O. A.; Graczykowski, L. K.; Graham, K. L.; Grelli, A.; Grigoras, A.; Grigoras, C.; Grigoriev, V.; Grigoryan, A.; Grigoryan, S.; Grinyov, B.; Grion, N.; Gronefeld, J. M.; Grosa, F.; Grosse-Oetringhaus, J. F.; Grosso, R.; Gruber, L.; Guber, F.; Guernane, R.; Guerzoni, B.
2016-01-01
Background: In the context of the investigation of the quark gluon plasma produced in heavy-ion collisions, hadrons containing heavy (charm or beauty) quarks play a special role for the characterization of the hot and dense medium created in the interaction. The measurement of the production of
Connecting QGP-Heavy Ion Physics to the Early Universe
Rafelski, Johann
2013-01-01
We discuss properties and evolution of quark-gluon plasma in the early Universe and compare to laboratory heavy ion experiments. We describe how matter and antimatter emerged from a primordial soup of quarks and gluons. We focus our discussion on similarities and differences between the early Universe and the laboratory experiments.
Connecting QGP-Heavy Ion Physics to the Early Universe
Rafelski, Johann
2013-10-01
We discuss properties and evolution of quark-gluon plasma in the early Universe and compare to laboratory heavy ion experiments. We describe how matter and antimatter emerged from a primordial soup of quarks and gluons. We focus our discussion on similarities and differences between the early Universe and the laboratory experiments.
Connecting QGP-Heavy Ion Physics to the Early Universe
Energy Technology Data Exchange (ETDEWEB)
Rafelski, Johann
2013-10-15
We discuss properties and evolution of quark-gluon plasma in the early Universe and compare to laboratory heavy ion experiments. We describe how matter and antimatter emerged from a primordial soup of quarks and gluons. We focus our discussion on similarities and differences between the early Universe and the laboratory experiments.
The ALICE experiment at the CERN LHC
Aamodt, K.; de Haas, A.P.; Grebenyuk, O.; Ivan, C.G.; Kamermans, R.; Mischke, A.; Nooren, G.J.L.; Oskamp, C.J.; Peitzmann, T.; Simili, E.; van den Brink, A.; van Eijndhoven, N.J.A.M.; Yuting, B.
2008-01-01
ALICE (A Large Ion Collider Experiment) is a general-purpose, heavy-ion detector at the CERN LHC which focuses on QCD, the strong-interaction sector of the Standard Model. It is designed to address the physics of strongly interacting matter and the quark-gluon plasma at extreme values of energy dens
Krzewicki, M
2013-01-01
In relativistic heavy-ion collisions a dense and hot medium is created. It is thought to be the quark-gluon plasma (QGP), a state of matter in which the quarks and gluons, normally confined in hadrons, are (quasi-) free. The QGP is believed to have existed in the first few microseconds after the Big
ALICE brochure (Spanish version)
Lefevre, C
2008-01-01
ALICE is one of the four big experiments for the LHC, the most powerful particle accelerator in the world, which will start up in 2008. ALICE will study the quark-gluon plasma, a state of matter that probably existed in the first moments of the universe.
Lattice QCD Results at Finite Temperature and Density
Fodor, Z
2003-01-01
Recent lattice results on QCD at finite temperatures and densities are reviewed. Two new and independent techniques give compatible results for physical quantities. The phase line separating the hadronic and quark-gluon plasma phases, the critical endpoint and the equation of state are discussed.
ALICE brochure (Polish version)
Lefevre, C
2008-01-01
ALICE is one of the four big experiments for the LHC, the most powerful particle accelerator in the world, which will start up in 2008. ALICE will study the quark-gluon plasma, a state of matter that probably existed in the first moments of the universe.
Theoretical Concepts for Ultra-Relativistic Heavy Ion Collisions
McLerran, Larry
2009-01-01
Various forms of matter may be produced in ultra-relativistic heavy ion collisions. These are the Quark Gluon Plasma, the Color Glass Condensate, the Glasma and Quarkyonic Matter. A novel effect that may be associated with topological charge fluctuations is the Chiral Magnetic Effect. I explain these concepts and explain how they may be seen in ultra-relativistic heavy ion collisions.
Cold Nuclear Matter Effects on Open and Hidden Heavy Flavor Production at the LHC
Vogt, R
2015-01-01
We discuss a number of cold nuclear matter effects that can modify open heavy flavor and quarkonium production in proton-nucleus collisions and could thus also affect their production in nucleus-nucleus collisions, in addition to hot quark-gluon plasma production. We show some results for $p+$Pb collisions at sqrt s = 5 TeV at the LHC.
ALICE brochure (French version)
Lefevre, C
2012-01-01
ALICE is one of the four big experiments for the LHC, the most powerful particle accelerator in the world, which started up in 2008. ALICE will study the quark-gluon plasma, a state of matter that probably existed in the first moments of the universe.
ALICE brochure (French version)
Lefevre, Christiane
2011-01-01
ALICE is one of the four big experiments for the LHC, the most powerful particle accelerator in the world, which started up in 2008. ALICE will study the quark-gluon plasma, a state of matter that probably existed in the first moments of the universe.
ALICE brochure (English version)
Marcastel, Fabienne
2014-01-01
ALICE is one of the four big experiments for the LHC, the most powerful particle accelerator in the world, which started up in 2008. ALICE studies the quark-gluon plasma, a state of matter that probably existed in the first moments of the universe.
ALICE brochure (German version)
Lefevre, C
2012-01-01
ALICE is one of the four big experiments for the LHC, the most powerful particle accelerator in the world, which started up in 2008. ALICE will study the quark-gluon plasma, a state of matter that probably existed in the first moments of the universe.
Cheynis, B
2013-01-01
ALICE is the only experiment at CERN specifically designed to study the Quark-Gluon Plasma, the hot and dense matter which is created in ultra relativistic heavy-ion collisions. - VZERO-A (CINVESTAV-UNAM Mexico): 2.8 328 cm away from Interaction Point - VZERO-C (IPN Lyon): -3.6 88 cm away from Interaction Point
ALICE brochure (English version)
Lefevre, C
2012-01-01
ALICE is one of the four big experiments for the LHC, the most powerful particle accelerator in the world, which started up in 2008. ALICE will study the quark-gluon plasma, a state of matter that probably existed in the first moments of the universe.
Evaporation/Hadronization Correspondence
Allahbakhshi, Davood
2016-01-01
A holographic duality is proposed between black hole evaporation in the bulk and hadronization (confinement) in dual field theory. Information paradox is discussed in this duality. We also propose that the recently introduced semi black brane solution is holographically dual to a mixed plasma of quarks, gluons and hadrons in global equilibrium.
Spinodal decomposition: An alternate mechanism of phase conversion
Indian Academy of Sciences (India)
P Shukla; A K Mohanty
2003-05-01
The scenario of homogeneous nucleation is investigated for a ﬁrst-order quark–hadron phase transition in a rapidly expanding background of quark gluon plasma. It is found that signiﬁcant supercooling is possible before hadronization begins. This study also suggests that spinodal decomposition competes with nucleation and may provide an alternative mechanism for phase conversion.
ALICE brochure (Norwegian version)
Lefevre, C
2009-01-01
ALICE is one of the four big experiments for the LHC, the most powerful particle accelerator in the world, which will start up in 2008. ALICE will study the quark-gluon plasma, a state of matter that probably existed in the first moments of the universe.
Lattice implementation of Abelian gauge theories with Chern-Simons number and an axion field arXiv
Figueroa, Daniel G.
Real time evolution of classical gauge fields is relevant for a number of applications in particle physics and cosmology, ranging from the early Universe to dynamics of quark-gluon plasma. We present a lattice formulation of the interaction between a $shift$-symmetric field and some $U(1)$ gauge sector, $a(x)\\tilde{F}_{\\mu\
Directory of Open Access Journals (Sweden)
Barnaföldi G.G.
2011-04-01
Full Text Available Resonance production and decay into pion pairs is simulated in a non-extensive quark matter with multi-particle interactions. Final state pion spectra are found to take the form of the Tsallis distribution, in accordance with measurements. It has also been shown that, if a large number of particles with these multi-particle interactions are constrained to a constant energy hyper-surface in phase space, the one-particle distribution is the Tsallis distribution.
qq(q)→qq(q) Reaction in Quark-Gluon Matter%夸克胶子物质内的qq(q)→qq(q)反应
Institute of Scientific and Technical Information of China (English)
马成程; 许晓明
2007-01-01
夸克胶子物质内的从夸克-夸克-反夸克到夸克-夸克-反夸克的散射过程会影响夸克物质和反夸克物质的热平衡化,其散射振幅是研究热平衡化的一个基础.依据微扰QCD理论,编制Fortran程序,推导了α4s阶的各个qq(q)→qq(q)散射费曼图的振幅平方和不同费曼图间的干涉项.
Clustering of Color Sources and the Equation of State of the QGP
Srivastava, Brijesh K
2012-01-01
Possible phase transition of strongly interacting matter from hadron to a quark-gluon plasma state have in the past received c onsiderable interest. It has been suggested that this problem might be treated by percolation theory. The clustering of color sources with percolation (CSPM) is used to determine the equation of state (EOS) and the transport coefficient of the Quark-Gl uon Plasma (QGP) produced in central A-A collisions at RHIC and LHC energies.
Indian Academy of Sciences (India)
Subrata Pal
2015-05-01
We review the transport models that are widely used to study the properties of the quark-gluon plasma formed in relativistic heavy-ion collisions at RHIC and LHC. We show that transport model analysis of two important and complementary observables, the anisotropic flow of bulk hadrons and suppression of hadron yields at high transverse momentum, provide exciting new information on the properties of the plasma formed.
PROCEEDINGS OF RIKIN BNL RESEARCH CENTER WORKSHOP - VOLUME 79
Energy Technology Data Exchange (ETDEWEB)
SAMIOS,N.
2006-02-16
Since the earliest days of ultra-relativistic heavy ion physics, there has been interest in strange particle production. Originally, an anomalously large strangeness production was believed to be a signature of the Quark Gluon Plasma. Now the flavor composition of the plasma as reflected in the ratios of abundances of strange and non-strange particles is believed by advocates to tell us the temperature and baryon number density of the Quark Gluon Plasma at decoupling. In addition, there are arguments that suggest that the abundances of strange particles might at intermediate energy or at non-central rapidity, signal the existence of a critical end point of phase transitions in the baryon number chemical potential temperature plane. The purpose of this workshop is to assess the current theoretical and experimental understanding of strangeness production for ultra-relativistic heavy ion collisions.
Longitudinal thermalization via the chromo-Weibel instability
Attems, Maximilian; Strickland, Michael
2013-01-01
Non-Abelian plasma instabilities play an important role in the non-equilibrium dynamics of a weakly coupled quark-gluon plasma. Using the discretized hard loop framework we calculate the time evolution of soft gluonic fields in a longitudinally free streaming background. Extrapolating our results to energies probed in relativistic heavy-ion collisions we find a pressure anisotropy that persists for a few fm/c. However, the chromofields quickly develop a Boltzmann longitudi- nal energy spectrum, suggesting fast longitudinal thermalization of the quark gluon plasma even though it remains momentum-space anisotropic. In this proceedings contribution we review our recent numerical results, present new results for the scaling of the isotropization time with the initial current fluctuation amplitude, and present tests of the gauge invariance of the extracted longitudinal spectra.
Energy Technology Data Exchange (ETDEWEB)
Horton, W. [Univ. of Texas, Austin, TX (United States). Inst. for Fusion Studies; Hu, G. [Globalstar LP, San Jose, CA (United States)
1998-07-01
The origin of plasma turbulence from currents and spatial gradients in plasmas is described and shown to lead to the dominant transport mechanism in many plasma regimes. A wide variety of turbulent transport mechanism exists in plasmas. In this survey the authors summarize some of the universally observed plasma transport rates.
Ganeev, Rashid A
2014-01-01
Preface; Why plasma harmonics? A very brief introduction Early stage of plasma harmonic studies - hopes and frustrations New developments in plasma harmonics studies: first successes Improvements of plasma harmonics; Theoretical basics of plasma harmonics; Basics of HHG Harmonic generation in fullerenes using few-cycle pulsesVarious approaches for description of observed peculiarities of resonant enhancement of a single harmonic in laser plasmaTwo-colour pump resonance-induced enhancement of odd and even harmonics from a tin plasmaCalculations of single harmonic generation from Mn plasma;Low-o
ARBOR, Nicolas
The strong interaction theory, Quantum Chromodynamic (QCD), predicts a new phase of nuclear matter at very high temperature and/or very high density. This state, which should have been the state of the Univers some microseconds after the Big Bang, is composed of deconfined quarks and gluons known as the quark-gluon plasma (QGP). The measurement of its composition and properties is a challenge for the nuclear physics of the 21st century and should lead to a better understanding of the fundamental symetries and mechanisms related to the quarks confinement inside hadrons and the strong interaction generally. The Large Hadron Collider (LHC) accelerator at CERN (European Organization for Nuclear Research) allows to reach the thermodynamic conditions required to create the quark-gluon plasma using ultra-relativistic heavy ion collisions (Pb). The ALICE experiment (A Large Ion Collider Experiment) allows to access several probes to characterize the QGP through particles reconstruction and. Among these probes, hi...
On Effective Degrees of Freedom in the Early Universe
Husdal, Lars
2016-01-01
We explore the effective degrees of freedom in the early Universe, from before the electroweak scale at a few femtoseconds after the Big Bang, until the last positrons disappeared a few minutes later. We first look at the established concepts of effective degrees of freedom for energy density, pressure and entropy density, and introduce effective degrees of freedom for number density as well. We discuss what happens with particle species as their temperature cools down from relativistic to semi- and non-relativistic temperatures, and then annihilates completely. This will affect the pressure as well as the entropy per particle. We also look at the transition from a quark-gluon plasma to a hadron gas. Using a list a known hadrons, we use a "cross-over" temperature of 214 MeV where the effective degrees of freedom for a quark-gluon plasma equals that of a hadron gas.
Indian Academy of Sciences (India)
Dinesh Kumar Srivastava
2001-08-01
The production of single photons in Pb+Pb collisions at the CERN SPS as measured by the WA98 experiment is analysed. A quark gluon plasma is assumed to be formed initially, which expands, cools, hadronizes, and undergoes freeze-out. A rich hadronic equation of state is used and the transverse expansion of the interacting system is taken into account. The recent estimates of photon production in quark-matter (at two loop level) along with the dominant reactions in the hadronic matter leading to photons are used. About half of the radiated photons are seen to have a thermal origin. The same treatment and the initial conditions provide a very good description to hadronic spectra measured by several groups and the intermediate mass dileptons measured by the NA50 experiment, lending a strong support to the conclusion that quark gluon plasma has been formed in these collisions. Predictions for RHIC and LHC energies are also given.
Recent progress in anisotropic hydrodynamics
Strickland, Michael
2016-01-01
The quark-gluon plasma created in a relativistic heavy-ion collisions possesses a sizable pressure anisotropy in the local rest frame at very early times after the initial nuclear impact and this anisotropy only slowly relaxes as the system evolves. In a kinetic theory picture, this translates into the existence of sizable momentum-space anisotropies in the underlying partonic distribution functions, . In such cases, it is better to reorganize the hydrodynamical expansion by taking into account momentum-space anisotropies at leading-order in the expansion instead of as a perturbative correction to an isotropic distribution. The resulting anisotropic hydrodynamics framework has been shown to more accurately describe the dynamics of rapidly expanding systems such as the quark-gluon plasma. In this proceedings contribution, I review the basic ideas of anisotropic hydrodynamics, recent progress, and present a few preliminary phenomenological predictions for identified particle spectra and elliptic flow.
Anisotropic hydrodynamics -- basic concepts
Florkowski, Wojciech; Ryblewski, Radoslaw; Strickland, Michael
2013-01-01
Due to the rapid longitudinal expansion of the quark-gluon plasma created in relativistic heavy ion collisions, potentially large local rest frame momentum-space anisotropies are generated. The magnitude of these momentum-space anisotropies can be so large as to violate the central assumption of canonical viscous hydrodynamical treatments which linearize around an isotropic background. In order to better describe the early-time dynamics of the quark gluon plasma, one can consider instead expanding around a locally anisotropic background which results in a dynamical framework called anisotropic hydrodynamics. In this proceedings contribution we review the basic concepts of the anisotropic hydrodynamics framework presenting viewpoints from both the phenomenological and microscopic points of view.
On Effective Degrees of Freedom in the Early Universe
Directory of Open Access Journals (Sweden)
Lars Husdal
2016-12-01
Full Text Available We explore the effective degrees of freedom in the early Universe, from before the electroweak scale at a few femtoseconds after the Big Bang until the last positrons disappeared a few minutes later. We look at the established concepts of effective degrees of freedom for energy density, pressure, and entropy density, and introduce effective degrees of freedom for number density as well. We discuss what happens with particle species as their temperature cools down from relativistic to semi- and non-relativistic temperatures, and then annihilates completely. This will affect the pressure and the entropy per particle. We also look at the transition from a quark-gluon plasma to a hadron gas. Using a list a known hadrons, we use a “cross-over” temperature of 214 MeV, where the effective degrees of freedom for a quark-gluon plasma equals that of a hadron gas.
Seltsamkeitsproduktion in ultrarelativistischen p+p-Kollisionen bei 158 GeV
Billmeier, Anja
Die Rekonstruktion der zeitlichen Evolution des Universums sowie der Komposition stellarer Objekte setzt die genaue Kenntnis des Verhaltens von Kernmaterie unter extremen Bedingungen voraus. Experimentell ist in ultrarelativistischen Schwerionenkollisionen die Erzeugung eines Zustandes hochdichter stark wechselwirkender Kernmaterie denkbar, in dem der Einschluss von Quarks und Gluonen in Hadronen aufgehoben ist (Quark-Gluon- Plasma). Ein solcher ¨Ubergang von hadronischer Materie in eine partonische Phase wird in der fr¨uhen Anfangsphase des Universums sowie im Innern von Neutronensternen vermutet. Die Formation eines Quark-Gluon-Plasmas soll dabei mit Hilfe geeigneter Obersvablen des gemessenen Endzustandes nachgewiesen werden. Das NA49-Experiment am CERN-SPS erlaubt die Messung einer Vielzahl hadronischer Observablen in hochenergetischen Kollisionen verschiedener Stoßsysteme und Einschussenergien. Eine relative Erh¨ohung der Produktion seltsamer Hadronen in Schwerionenreaktionen im Vergleich zu elementa...
Thermodynamics of lattice QCD with two light quark flavours on A 16{sup 3} x 8 lattice II.
Energy Technology Data Exchange (ETDEWEB)
Gottlieb, S.; Heller, U. M.; Kennedy, A. D.; Kim, S.; Kogut, J. B.; Liu, C.; Renken, R. L.; Sinclair, D. K.; Sugar, R. L.; Toussaint, D.; Wang, K. C.; High Energy Physics; Indiana Univ.; Florida State Univ.; Seoul National Univ.; Univ. of Illinois; Morgan Stanley & Co. Inc.; Univ. of Central Florida; Univ. of California; Univ. of Arizona; China Graduate School of Theology
1997-01-01
We have extended our earlier simulations of the high-temperature behavior of lattice QCD with two light flavors of staggered quarks on a 16{sup 3}x8 lattice to a lower quark mass (m{sub q}=0.00625). The transition from hadronic matter to a quark-gluon plasma is observed at 6/g{sup 2}=5.49(2) corresponding to a temperature of {Tc}{approx}140 MeV. We present measurements of observables which probe the nature of the quark-gluon plasma and serve to distinguish it from hadronic matter. Although the transition is quite abrupt, we have seen no indications that it is first order.
Thermodynamics of lattice QCD with two light quarks on a 16{sup 3}{times}8 lattice. II
Energy Technology Data Exchange (ETDEWEB)
Gottlieb, S. [Department of Physics, Indiana University, Bloomington, Indiana 47405 (United States); Heller, U.M.; Kennedy, A.D. [SCRI, The Florida State University, Tallahassee, Florida 32306-4052 (United States); Kim, S. [Center for Theoretical Physics, Seoul National University, Seoul (Korea); Kogut, J.B. [Department of Physics, University of Illinois, 1110 West Green Street, Urbana, Illinois 61801 (United States); Liu, C. [Morgan Stanley and Co. Inc., 1585 Broadway, New York, New York 10036 (United States); Renken, R.L. [Department of Physics, University of Central Florida, Orlando, Florida 32816 (United States); Sinclair, D.K. [HEP Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States); Sugar, R.L. [Department of Physics, University of California, Santa Barbara, California 93106 (United States); Toussaint, D. [Department of Physics, University of Arizona, Tucson, Arizona 85721 (United States); Wang, K.C. [China Graduate School of Theology, 5 Devon Rd, Kowloon Tong, Kowloon (Hong Kong)
1997-06-01
We have extended our earlier simulations of the high-temperature behavior of lattice QCD with two light flavors of staggered quarks on a 16{sup 3}{times}8 lattice to a lower quark mass (m{sub q}=0.00625). The transition from hadronic matter to a quark-gluon plasma is observed at 6/g{sup 2}=5.49(2) corresponding to a temperature of T{sub c}{approx}140 MeV. We present measurements of observables which probe the nature of the quark-gluon plasma and serve to distinguish it from hadronic matter. Although the transition is quite abrupt, we have seen no indications that it is first order. {copyright} {ital 1997} {ital The American Physical Society}
Heavy-flavor production and medium properties in high-energy nuclear collisions. What next?
Energy Technology Data Exchange (ETDEWEB)
Aarts, G.; Allton, C. [Swansea University, Swansea (United Kingdom); Aichelin, J.; Gossiaux, P.B.; Nahrgang, M. [Universite de Nantes, SUBATECH, Ecole des Mines de Nantes, Nantes (France); Arnaldi, R.; Scomparin, E. [INFN, Sezione di Torino, Torino (Italy); Bass, S.A. [Duke University, Durham, NC (United States); Bedda, C.; Grelli, A.; Trzeciak, B.; Doremalen, L. van; Vermunt, L.; Vigolo, S. [Utrecht University, Institute for Subatomic Physics, Utrecht (Netherlands); Brambilla, N. [Technische Universitaet Muenchen, Physik-Department and Excellence Cluster Universe, Garching (Germany); Technische Universitaet Muenchen, Institute for Advanced Study, Munich (Germany); Bratkovskaya, E. [GSI Helmholtzzentrum fuer Schwerionenforschung, Research Division and ExtreMe Matter Institute EMMI, Darmstadt (Germany); Frankfurt University, Institute for Theoretical Physics, Frankfurt am Main (Germany); Braun-Munzinger, P. [GSI Helmholtzzentrum fuer Schwerionenforschung, Research Division and ExtreMe Matter Institute EMMI, Darmstadt (Germany); Ruprecht-Karls-Universitaet Heidelberg, Physikalisches Institut, Heidelberg (Germany); Bruno, G.E. [Dipartimento di Fisica and INFN, Bari (Italy); European Organization for Nuclear Research, Geneva (Switzerland); Dahms, T. [Technische Universitaet Muenchen, Physik-Department and Excellence Cluster Universe, Garching (Germany); Das, S.K. [University of Catania, Catania (Italy); Dembinski, H.; Schmelling, M. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Djordjevic, M. [University of Belgrade, Institute of Physics, Belgrade (Serbia); Ferreiro, E. [Universidad de Santiago de Compostela, Santiago de Compostela (Spain); Frawley, A. [Florida State University, Tallahassee, FL (United States); Granier de Cassagnac, R.; Jo, M.; Nguyen, M. [Ecole Polytechnique, Laboratoire Leprince-Ringuet, Palaiseau (France); He, M. [Nanjing University of Science and Technology, Department of Applied Physics, Nanjing (China); Horowitz, W.A. [University of Cape Town, Department of Physics, Rondebosch (South Africa); Innocenti, G.M. [Massachusetts Institute of Technology, Cambridge, MA (United States); Kaczmarek, O. [Key Laboratory of Quark and Lepton Physics (MOE) and Institute of Particle Physics, Central China Normal University, Wuhan (China); University of Bielefeld, Bielefeld (Germany); Kuijer, P.G. [National Institute for Subatomic Physics, Amsterdam (Netherlands); Laine, M. [University of Bern, AEC, Institute for Theoretical Physics, Bern (Switzerland); Lombardo, M.P. [INFN - Laboratori Nazionali di Frascati, Frascati (Italy); Mischke, A. [Utrecht University, Institute for Subatomic Physics, Utrecht (Netherlands); National Institute for Subatomic Physics, Amsterdam (Netherlands); Munhoz, M.G.; Suaide, A.A.P. [Universidade de Sao Paulo (USP), Sao Paulo (Brazil); Oliveira da Silva, A.C.; Zanoli, H.J.C. [Utrecht University, Institute for Subatomic Physics, Utrecht (Netherlands); Universidade de Sao Paulo (USP), Sao Paulo (Brazil); Petreczky, P. [Brookhaven National Laboratory, Upton, NY (United States); Rothkopf, A. [Ruprecht-Karls-Universitaet Heidelberg, Institute for Theoretical Physics, Heidelberg (Germany); Song, T. [Frankfurt University, Institute for Theoretical Physics, Frankfurt am Main (Germany); Stachel, J. [Ruprecht-Karls-Universitaet Heidelberg, Physikalisches Institut, Heidelberg (Germany); Tolos, L. [Frankfurt Institute for Advanced Studies (FIAS), Frankfurt (Germany); Institut de Ciencies de l' Espai (IEEC-CSIC), Bellaterra (Spain); Uras, A. [Domaine Scientifique de la Doua, Institute of Nuclear Physics, Villeurbanne Cedex (France); Xu, N. [Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Ye, Z. [University of Illinois, Chicago, IL (United States); Zhuang, P. [Tsinghua University, Beijng Shi (China)
2017-05-15
Open and hidden heavy-flavor physics in high-energy nuclear collisions are entering a new and exciting stage towards reaching a clearer understanding of the new experimental results with the possibility to link them directly to the advancement in lattice Quantum Chromo-Dynamics (QCD). Recent results from experiments and theoretical developments regarding open and hidden heavy-flavor dynamics have been debated at the Lorentz Workshop Tomography of the Quark-Gluon Plasma with Heavy Quarks, which was held in October 2016 in Leiden, The Netherlands. In this contribution, we summarize identified common understandings and developed strategies for the upcoming five years, which aim at achieving a profound knowledge of the dynamical properties of the quark-gluon plasma. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Fleck, Martin [Heidelberg University (Germany); Collaboration: ALICE-Collaboration
2015-07-01
Heavy quarks (charm and beauty), only produced in the initial hard scattering processes, constitute an important way to probe features of the Quark-Gluon Plasma. However, suppression effects that are seen in Pb-Pb collisions in comparison to p-p results can be regarded as a property of the Quark-Gluon Plasma after non-QGP nuclear effects in the study of proton-nucleus collisions have been quantified. For this purpose the ALICE TPC and TRD were used to measure semi-leptonic decays of heavy-flavoured hadrons, where especially the TRD electron identification capability contributes to the results. The procedure of the analysis of p-Pb LHC data of 2013 is explained and first results are shown.
Srivastava, Dinesh K; Mustafa, Munshi G
2016-01-01
We emphasize that a knowledge of energy and entropy densities of quark gluon plasma - a thermalized de-confined matter, formed in relativistic heavy ion collisions fixes the formation temperature and the product of gluon fugacity and formation time uniquely, {\\em provided} we know the relative fugacities of quarks and gluons. This also provides that a smaller formation time would imply larger fugacities for partons. Next we explore the limits of chemical equilibration of partons during the initial stages in relativistic collision of heavy nuclei. The experimentally measured rapidity densities of transverse energy and charged particle multiplicity at RHIC and LHC energies are used to estimate the energy and number densities with the assumption of formation of a thermally equilibrated quark gluon plasma which may be chemically equilibrated to the same or differing extents for quarks and gluons. The estimates are found to be very sensitive to the correction factor used for the Bj\\"{o}rken energy density for iden...
Strangeness at high temperatures: from hadrons to quarks.
Bazavov, A; Ding, H-T; Hegde, P; Kaczmarek, O; Karsch, F; Laermann, E; Maezawa, Y; Mukherjee, Swagato; Ohno, H; Petreczky, P; Schmidt, C; Sharma, S; Soeldner, W; Wagner, M
2013-08-23
Appropriate combinations of up to fourth order cumulants of net strangeness fluctuations and their correlations with net baryon number and electric charge fluctuations, obtained from lattice QCD calculations, have been used to probe the strangeness carrying degrees of freedom at high temperatures. For temperatures up to the chiral crossover, separate contributions of strange mesons and baryons can be well described by an uncorrelated gas of hadrons. Such a description breaks down in the chiral crossover region, suggesting that the deconfinement of strangeness takes place at the chiral crossover. On the other hand, the strangeness carrying degrees of freedom inside the quark gluon plasma can be described by a weakly interacting gas of quarks only for temperatures larger than twice the chiral crossover temperature. In the intermediate temperature window, these observables show considerably richer structures, indicative of the strongly interacting nature of the quark gluon plasma.
Strangeness at high temperatures: from hadrons to quarks
Bazavov, A; Hegde, P; Kaczmarek, O; Karsch, F; Laermann, E; Maezawa, Y; Mukherjee, Swagato; Ohno, H; Petreczky, P; Schmidt, C; Sharma, S; Soeldner, W; Wagner, M
2013-01-01
Appropriate combinations of up to fourth order cumulants of net strangeness fluctuations and their correlations with net baryon number and electric charge fluctuations, obtained from lattice QCD calculations, have been used to probe the strangeness carrying degrees of freedom at high temperatures. For temperatures up to the chiral crossover separate contributions of strange mesons and baryons can be well described by an uncorrelated gas of hadrons. Such a description breaks down in the chiral crossover region, suggesting that the deconfinement of strangeness takes place at the chiral crossover. On the other hand, the strangeness carrying degrees of freedom inside the quark gluon plasma can be described by a weakly interacting gas of quarks only for temperatures larger than twice the chiral crossover temperature. In the intermediate temperature window these observables show considerably richer structures, indicative of the strongly interacting nature of the quark gluon plasma.
Kinetic evolution of the glasma and thermalization in heavy ion collisions
Huang, Xu-Guang
2014-01-01
In relativistic heavy ion collisions, a highly occupied gluonic matter is created shortly after initial impact, which is in a non-thermal state and often referred to as the Glasma. Successful phenomenology suggests that the glasma evolves rather quickly toward the thermal quark-gluon plasma and a hydrodynamic behavior emerges at very early time $\\sim \\hat{o}(1)$ fm/c. Exactly how such "apparent thermalization" occurs and connects the initial conditions to the hydrodynamic onset, remains a significant challenge for theory as well as phenomenology. We briefly review various ideas and recent progress in understanding the approach of the glasma to the thermalized quark-gluon plasma, with an emphasis on the kinetic theory description for the evolution of such far-from-equilibrium and highly overpopulated, thus weakly-coupled yet strongly interacting glasma.
Bulk viscosity-driven suppression of shear viscosity effects on the flow harmonics at RHIC
Noronha-Hostler, J; Grassi, F
2014-01-01
The interplay between shear and bulk viscosities on the flow harmonics, $v_n$'s, at RHIC is investigated using the newly developed relativistic 2+1 hydrodynamical code v-USPhydro that includes bulk and shear viscosity effects both in the hydrodynamic evolution and also at freeze-out. While shear viscosity is known to attenuate the flow harmonics, we find that the inclusion of bulk viscosity decreases the shear viscosity-induced suppression of the flow harmonics bringing them closer to their values in ideal hydrodynamical calculations. Depending on the value of the bulk viscosity to entropy density ratio, $\\zeta/s$, in the quark-gluon plasma, the bulk viscosity-driven suppression of shear viscosity effects on the flow harmonics may require a re-evaluation of the previous estimates of the shear viscosity to entropy density ratio, $\\eta/s$, of the quark-gluon plasma previously extracted by comparing hydrodynamic calculations to heavy ion data.
6th Conference and Workshop on Strong and Electroweak Matter
Kainulainen, Kimmo; Kajantie, Keijo; Rummukainen, Kari; Strong and Electroweak Matter 2004; SEWM 2004
2004-01-01
This volume presents an authoritative review of the physics of strongly and electroweakly interacting elementary particle matter in extreme conditions that prevailed in the very early Universe, and which are being recreated in high energy physics laboratories today. Exciting, high-quality experimental results from RHIC collider at Brookhaven, collected since summer 2000, suggest that strongly interacting quark-gluon plasma has indeed been produced. The study of these phenomena will form an important part of theoretical particle and nuclear physics for years to come. Based on the discussions of more than a hundred experts at the Strong and Electroweak Matter 2004 Meeting, this volume contains an up-to-date overview of present ideas on QCD matter: quark-gluon plasma in heavy ion collisions, phase structure, kinetics, thermalization and transport properties. Also discussed are topics related to the cosmology of the early Universe, dark matter, inflation and creation of particle-antiparticle asymmetries. Both an...
Massively parallel simulations of relativistic fluid dynamics on graphics processing units with CUDA
Bazow, Dennis; Strickland, Michael
2016-01-01
Relativistic fluid dynamics is a major component in dynamical simulations of the quark-gluon plasma created in relativistic heavy-ion collisions. Simulations of the full three-dimensional dissipative dynamics of the quark-gluon plasma with fluctuating initial conditions are computationally expensive and typically require some degree of parallelization. In this paper, we present a GPU implementation of the Kurganov-Tadmor algorithm which solves the 3+1d relativistic viscous hydrodynamics equations including the effects of both bulk and shear viscosities. We demonstrate that the resulting CUDA-based GPU code is approximately two orders of magnitude faster than the corresponding serial implementation of the Kurganov-Tadmor algorithm. We validate the code using (semi-)analytic tests such as the relativistic shock-tube and Gubser flow.