38 research outputs found

    Chaos Driven by Soft-Hard Mode Coupling in Thermal Yang-Mills Theory

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    We argue on a basis of a simple few mode model of SU(2) Yang-Mills theory that the color off-diagonal coupling of the soft plasmon to hard thermal excitations of the gauge field drives the collective plasma oscillations into chaotic motion despite the presence of the plasmon mass.Comment: 10 pages, REVTeX, revised manuscript, new titl

    Azimuthal asymmetry in transverse energy flow in nuclear collisions at high energies

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    The azimuthal pattern of transverse energy flow in nuclear collisions at RHIC and LHC energies is considered. We show that the probability distribution of the event-by-event azimuthal disbalance in transverse energy flow is essentially sensitive to the presence of the semihard minijet component.Comment: 6 pages, 2 figure

    Possible scenarios for soft and semi-hard components structure in central hadron-hadron collisions in the TeV region

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    Possible scenarios in hh collisions in the TeV regions are discussed in full phase space. It is shown that at such high energies one should expect strong KNO scaling violation and a ln(s) increase of the average charged multiplicity of the semi-hard component, resulting in a huge mini-jet production.Comment: 20 pages, 9 PS figures included, LaTeX2e with AMSmath, epsfi

    Non-abelian plane waves and stochastic regimes for (2+1)-dimensional gauge field models with Chern-Simons term

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    An exact time-dependent solution of field equations for the 3-d gauge field model with a Chern-Simons (CS) topological mass is found. Limiting cases of constant solution and solution with vanishing topological mass are considered. After Lorentz boost, the found solution describes a massive nonlinear non-abelian plane wave. For the more complicate case of gauge fields with CS mass interacting with a Higgs field, the stochastic character of motion is demonstrated.Comment: LaTeX 2.09, 13 pages, 11 eps figure

    Chiral Symmetry in Charmonium - Pion Cross Section

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    We perform a non-perturbative calculation of the J/ΨπJ/\Psi-\pi cross section using a SU(2)×SU(2)SU(2)\times SU(2) effective Lagrangian. Our results differ from those of previous calculations, specially in the description of vertices involving pions.Comment: 6 pages, RevTeX including 2 figures in eps file

    Light propagation in non-trivial QED vacua

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    Within the framework of effective action QED, we derive the light cone condition for homogeneous non-trivial QED vacua in the geometric optics approximation. Our result generalizes the ``unified formula'' suggested by Latorre, Pascual and Tarrach and allows for the calculation of velocity shifts and refractive indices for soft photons travelling through these vacua. Furthermore, we clarify the connection between the light velocity shift and the scale anomaly. This study motivates the introduction of a so-called effective action charge that characterizes the velocity modifying properties of the vacuum. Several applications are given concerning vacuum modifications caused by, e.g., strong fields, Casimir systems and high temperature.Comment: 13 pages, REVTeX, 3 figures, to appear in Phys. Rev.

    Supersymmetry and Integrability in Planar Mechanical Systems

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    We present an N=2-supersymmetric mechanical system whose bosonic sector, with two degrees of freedom, stems from the reduction of an SU(2) Yang-Mills theory with the assumption of spatially homogeneous field configurations and a particular ansatz imposed on the gauge potentials in the dimensional reduction procedure. The Painleve test is adopted to discuss integrability and we focus on the role of supersymmetry and parity invariance in two space dimensions for the attainment of integrable or chaotic models. Our conclusion is that the relationships among the parameters imposed by supersymmetry seem to drastically reduce the number of possibilities for integrable interaction potentials of the mechanical system under consideration.Comment: 20 pages, 3 figure

    B_c Meson Production in Nuclear Collisions at RHIC

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    We study quantitatively the formation and evolution of B_c bound states in a space-time domain of deconfined quarks and gluons (quark-gluon plasma, QGP). At the Relativistic Heavy Ion Collider (RHIC) one expects for the first time that typical central collisions will result in multiple pairs of heavy (in this case charmed) quarks. This provides a new mechanism for the formation of heavy quarkonia which depends on the properties of the deconfined region. We find typical enhancements of about 500 fold for the B_c production yields over expectations from the elementary coherent hadronic B_c-meson production scenario. The final population of bound states may serve as a probe of the plasma phase parameters.Comment: 9 Pages, 11 Postscript Figure

    Superposition effect and clan structure in forward-backward multiplicity correlations

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    The main purpose of this paper is to discuss the link between forward-backward multiplicity correlations properties and the shape of the corresponding final charged particle multiplicity distribution in various classes of events in different collisions. It is shown that the same mechanism which explains the shoulder effect and the H_n vs. n oscillations in charged particle multiplicity distributions, i.e., the weighted superposition of different classes of events with negative binomial properties, reproduces within experimental errors also the forward-backward multiplicity correlation strength in e+e- annihilation at LEP energy and allows interesting predictions for pp collisions in the TeV energy region, to be tested at LHC, for instance with the ALICE detector. We limit ourselves at present to study substructures properties in hadron-hadron collisions and e+e- annihilation; they are examined as ancillary examples in the conviction that their understanding might be relevant also in other more complex cases.Comment: 16 page
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