1,759 research outputs found

    Matter formed at the BNL relativistic heavy ion collider

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    We suggest that the "new form of matter" found just above TcT_c by RHIC is made up of tightly bound quark-antiquark pairs, essentially 32 chirally restored (more precisely, nearly massless) mesons of the quantum numbers of π\pi, σ\sigma, ρ\rho and a1a_1. Taking the results of lattice gauge simulations (LGS) for the color Coulomb potential from the work of the Bielefeld group and feeding this into a relativistic two-body code, after modifying the heavy-quark lattice results so as to include the velocity-velocity interaction, all ground-state eigenvalues of the 32 mesons go to zero at TcT_c just as they do from below TcT_c as predicted by the vector manifestation (VM in short) of hidden local symmetry. This could explain the rapid rise in entropy up to TcT_c found in LGS calculations. We argue that how the dynamics work can be understood from the behavior of the hard and soft glue.Comment: Final versio

    Query Expansion Using PRF-CBD Approach for Documents Retrieval

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    Heavy Quarkonia and Quark Drip Lines in Quark-Gluon Plasma

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    Using the potential model and thermodynamical quantities obtained in lattice gauge calculations, we determine the spontaneous dissociation temperatures of color-singlet quarkonia and the `quark drip lines' which separate the region of bound QQˉQ\bar Q states from the unbound region. The dissociation temperatures of J/ψJ/\psi and χb\chi_b in quenched QCD are found to be 1.62TcT_c and 1.18Tc1.18T_c respectively, in good agreement with spectral function analyses. The dissociation temperature of J/ψJ/\psi in full QCD with 2 flavors is found to be 1.42TcT_c. For possible bound quarkonium states with light quarks, the characteristics of the quark drip lines severely limit the stable region close to the phase transition temperature. Bound color-singlet quarkonia with light quarks may exist very near the phase transition temperature if their effective quark mass is of the order of 300-400 MeV and higher.Comment: 8 pages, 2 figures, in LaTex, invited talk presented at the International Conference on Strangeness in Quark Matter, UCLA, March 26-31, 200

    Chiral transition and deconfinement transition in QCD with the highly improved staggered quark (HISQ) action

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    We report preliminary results on the chiral and deconfinement aspects of the QCD transition at finite temperature using the Highly Improved Staggered Quark (HISQ) action on lattices with temporal extent of N_{\tau}=6 and 8. The chiral aspects of the transition are studied in terms of quark condensates and the disconnected chiral susceptibility. We study the deconfinement transition in terms of the strange quark number susceptibility and the renormalized Polyakov loop. We made continuum estimates for some quantities and find reasonably good agreement between our results and the recent continuum extrapolated results obtained with the stout staggered quark action.Comment: Talk presented by P. Petreczky at workshop Dense Matter 2010, April 6-9, Stellenbosch, South Africa, to be published in the proceeding

    Ergonomic and work safety evaluation criteria of process excellence in the foundry industry

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    The article presents a concept of criteria assessment called the “process excellence” for ergonomics and work safety in enterprises of the foundry industry as well as points to the possibility of its application

    Classical Strongly Coupled QGP I: The Model and Molecular Dynamics Simulations

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    We propose a model for the description of strongly interacting quarks and gluon quasiparticles at T=(13)TcT=(1-3)T_c, as a classical and nonrelativistic colored Coulomb gas. The sign and strength of the inter-particle interactions are fixed by the scalar product of their classical {\it color vectors} subject to Wong's equations. The model displays a number of phases as the Coulomb coupling is increased ranging from a gas, to a liquid, to a crystal with antiferromagnetic-like color ordering. We analyze the model using Molecular Dynamics (MD) simulations and discuss the density-density correlator in real time. We extract pertinent decorrelation times, diffusion and viscosity constants for all phases. The classical results when extrapolated to the sQGP suggest that the phase is liquid-like, with a diffusion constant D0.1/TD\approx 0.1/T and a bulk viscosity to entropy density ratio η/s1/3\eta/s\approx 1/3.Comment: 11 pages, 14 figure

    Magnetoelectricity at room temperature in Bi0.9-xTbxLa0.1FeO3 system

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    Magnetoelectric compounds with the general formula, Bi0.9-xRxLa0.1FeO3 (R =Gd, Tb, Dy, etc.), have been synthesized. These show the coexistence of ferroelectricity and magnetism, possess high dielectric constant and exhibit magnetoelectric coupling at room temperature. Such materials may be of great significance in basic as well as applied research.Comment: 11 pages of text and figure

    Heavy Quark Free Energies and Screening in SU(2) Gauge Theory

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    We investigate the singlet, triplet and colour average heavy quark free energies in SU(2) pure gauge theory at various temperatures T. We focus on the long distance behaviour of the free energies, studying in particular the temperature dependence of the string tension and the screening masses. The results are qualitatively similar to the SU(3) scenario, except near the critical temperature Tc of the deconfining transition. Finally we test a recently proposed method to renormalize the Polyakov loop.Comment: 5 pages, 4 figures, contribution to the Proceedings of SEWM 2002 (Heidelberg

    Critical Behavior of J/psi across the Phase Transition from QCD sum rules

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    We study behavior of J/psi in hot gluonic matter using QCD sum rules. Taking into account temperature dependences of the gluon condensates extracted from lattice thermodynamics for the pure SU(3) system, we find that the mass and width of J/psi exhibit rapid change across the critical temperature.Comment: 5 pages, 3 figures. Poster contribution for Quark Matter 2008. To be published in the proceeding
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