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Register a new userPossible Striking Signals for a Quark-Gluon Plasma at RHIC
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S.J. Lindenbaum
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We believe that one can have serious reservations as to whether heavy ion collisions (e.g. 100 GeV/n Au + 100 GeV/n Au) can lead to Thermal and Chemical equilibrium over large regions (particularly if it is assumed this happens whenever QGP is produced at RHIC-that is if it is produced). It is at present not clear that the collision dynamics and times available will lead to this. An alternate scenario proposed by Van Hove where localized in rapidity bubbles of plasma may well be more probable, and may well occur at least some of the time, and some of the time mainly survive to the final state. If this occurs we have developed a series of event generators to extend and describe these phenomena. A Van Hove type[6,7] spherical bubble at eta=0 is embedded in a resonable event generator in qualitative agreement with Hijing etc[12]. The plasma bubble hadronized at a temperature of 170 Mev according to the model developed by Koch, Muller and Rafelski[21]. The amount of available bubble energy is selected by that in a small central circular cross-section of radius approx 1.3fm or 2.5fm in 100 Gev/n Au+AU, central events The results predict Possible Striking Signals for a QGP. We are also applying these techniques to investigating Kharzeev and Pisarski bubbles of metastable vacua with odd CP.
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We calculate transport coefficients of the quark-gluon plasma (QGP) within the dynamical quasiparticle model (DQPM) by explicitly computing the parton interaction rates as a function of temperature $T$ and baryon chemical potential $mu_B$ on the basis of the DQPM couplings and partonic propagators. The latter are extracted from lattice QCD by matching the equation of state, entropy density and energy density at $mu_B$= 0. For baryon chemical potentials $0 leq mu_B leq 500 MeV$ we employ a scaling Ansatz for the effective coupling which was shown before to lead to thermodynamic consistent results in this range. We compute the ratio of the shear and bulk viscosities to the entropy density, i.e. $eta/s$ and $zeta/s$, the electric conductivity $sigma_0/T$ as well as the baryon diffusion coefficient $kappa_B$ and compare to related approaches from the literature. We find that the ratios $eta/s$ and $zeta/s$ as well as $sigma_0/T$ are in accord with the results from lattice QCD at $mu_B$=0 and only weakly depend on the ratio $T/T_c(mu_B)$ where $T_c(mu_B)$ denotes the critical temperature at finite baryon chemical potential.
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