Mon·Oct 24, 2005Monday·October 24, 2005

1. 01*

   The screening length in hot QCD

   O.Kaczmarek🇩🇪 · F.Zantow🇺🇸

   We discuss the temperature dependence of the screening lengths in quenched and full QCD using the non-perturbative lattice approach. We analyze the temperature dependence of distances which are defined as moments of quark antiquark free energies. These distance scales are supposed to describe the geometric size of partonic clouds which screen static charges in a medium and characterize distances beyond which the quark antiquark free energy is to large extent dominated by medium effects. At asymptotic high temperatures these moments can be related to the inverse Debye mass. In our numeric analysis we find that these moments drop rapidly in the vicinity of the phase transition and indicate distances which are about twice as large as the inverse Debye mass found in earlier studies. Our analysis supports recent findings that indicate that $J/\psi$ will show significant medium modifications only at temperatures well above $T_c$.

   hep-latPoS(2006)·11 citations
2. 02*

   Static quark anti-quark free and internal energy in 2-flavor QCD and bound states in the QGP

   O.Kaczmarek🇩🇪 · F.Zantow🇺🇸

   We present results on heavy quark free energies in 2-flavour QCD. The temperature dependence of the interaction between static quark anti-quark pairs will be analyzed in terms of temperature dependent screening radii, which give a first estimate on the medium modification of (heavy quark) bound states in the quark gluon plasma. Comparing those radii to the (zero temperature) mean squared charge radii of cha rmonium states indicates that the $J/\psi$ may survive the phase transition as a bound state, while ${\chi }_c$ and ${\psi }^{\prime }$ are expected to show significant thermal modifications at temperatures close to the transition. Furthermore we will analyze the relation between heavy quark free energies, entropy contributions and internal energy and discuss their relation to potential models used to analyze the melting of heavy quark bound states above the deconfinement temperature. Results of different groups and various potential models for bound states in the deconfined phase of QCD are compared.

   hep-latPoS(2006)·44 citations
3. 03*

   Could Spin-Charge Separation be the Source of Confinement?

   Antti J. Niemi🇸🇪

   Yang-Mills gauge field with gauge group SU(2) decomposes into a single charge neutral complex vector, and two spinless charged scalar fields. At high energies these constituents are tightly confined into each other by a compact U(1) interaction, and the Yang-Mills Lagrangian describes the dynamics of asymptotically free massless gauge vectors. But in a low energy and finite density environment the interaction between the constituents can become weak, and a spin-charge separation may occur. We suggest that the separation between the spin and charge with the ensuing condensation of the charged scalars takes place when the Yang-Mills theory enters confinement. The confining phase becomes then surprisingly similar to the superconducting phase of a high-$T_c$ superconductor.

   ↳ hep-phcond-mat.str-elhep-lathep-thAIP Conf.Proc.(2006)·5 citations
4. 04*

   A Weibel Instability in the Melting Color Glass Condensate

   Paul Romatschke🇩🇪 · Raju Venugopalan🇺🇸

   Based on hep-ph/0510121, we discuss further the numerical study of classical SU(2) 3+1-D Yang-Mills equations for matter produced in a high energy heavy ion collision. The growth of the amplitude of fluctuations as $\exp (\Gamma \sqrt{g^2\mu \tau })$ (where $g^2\mu$ is a scale arising from the saturation of gluons in the nuclear wavefunction) is shown to be robust over a wide range of initial amplitudes that violate boost invariance. We argue that this growth is due to a non-Abelian Weibel instability, the scale of which is set by a dynamically generated plasmon mass. We find good agreement when we relate $\Gamma$ to the prediction from kinetic theory.

   ↳ hep-phhep-latnucl-thEPJA(2006)·66 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.