791 research outputs found

    Freezeout of resonances and nuclear fragments at RHIC

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    We quantify the conditions at which ``composites'', the resonances and bound states d,He3d,He^3 are produced at RHIC. Using Hubble-like model for late stages, one can analytically solve the rate equations and also calculate the relevant optical depth factors. We calculate also the modification of ρ\rho masse and width, and predict a radiacal shape change of σ\sigma.Comment: 6 pages, proccedings of 19th Winter Workshop on Nuclear Dynamics, Breckenridge, Colorado, February 200

    QCD phases at high density and instantons

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    The talk is an introduction into diquark condensation phenomena which occur in QCD at high energy density. They are driven by instantons and instanton-antiinstanton pairs (or ``molecules''), which generate attraction in some qq channels. A number of phases is possible, with or without restoration of chiral symmetry: the work is not finished and we do not yet know which take place in real QCD. We also emphasize that specific diquark correlations play a significant role in baryon structure, in particular making that of a nucleon very different of a Δ\Delta (or other member of a decuplet). This ``small NcN_c'' scenario based on comparison to QCD with two colors is contrasted with the ``large NcN_c'' one.Comment: invited talk at "QCD at finite baryon density", Bielefeld, 199

    Anisotropy of photon production: Initial eccentricity or magnetic field

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    Recent measurements of the azimuthal anisotropy of direct photons in heavy-ion collisions at the energies of RHIC show that it is of the same order as the hadronic one. This finding appears to contradict the expected dominance of photon production from a quark-gluon plasma at an early stage of a heavy-ion collision. A possible explanation of the strong azimuthal anisotropy of the photons, given recently, is based on the presence of a large magnetic field in the early phase of a collision. In this letter, we propose a method to experimentally measure the degree to which a magnetic field in heavy-ion collisions is responsible for the observed anisotropy of photon production. The experimental test proposed in this letter may potentially change our understanding of the non-equilibrium stage and possible thermalization in heavy-ion collisions.Comment: 4 pages, 3 figures; version accepted for publication: discussions extended, MC calculations adde

    Strongly Coupled Quark-Gluon Plasma: The Status Report

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    RHIC data have shown robust collective flows, strong jet and charm quenching, and charm flow. Recently ``conical flows'' from damped jets were seen. Non-Abelian classical strongly coupled plasmas were introduced and studied via molecular dynamics, with first results for its transport (diffusion and viscosity) reported. Quantum-mechanical studies reveal the survival for T>TcT>T_c of the lowest binary states, including colored ones, and also of some manybody ones such as baryons. ``Polymeric chains'' qˉ.g.g...q\bar q.g.g... q are also bound in some range of TT, perhaps the progenitors of the QCD strings. AdS/CFT applications advanced to a completely new level of detail: they now include studies of thermal heavy quark motion, jet quenching and even conical flow. Confinement is however still beyond simply strong coupling: its de-facto inclusion the so called AdS/QCD approach is so far added as a model, while true understanding may probably only come from further insights into the monopole dynamics.Comment: It is brief review of the field, in 14 pages, written for proceedings of Continuous Advances in QCD, April 2006. As the progress is very rapid, it includes several new papers which appeared between April and August. The version 2 has more references and few statements get clarified bette
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