Quarkonia Correlators Above Deconfinement

We study the quarkonia correlators above deconfinement using the potential model with screened temperature-dependent potentials. We find that while the qualitative features of the spectral functions, such as the survival of the 1S state, can be reproduced by potential models, the temperature dependence of the correlators disagree with the recent lattice data.Comment: 21 pages, 26 eps figure

Identification of Piecewise Linear Models of Complex Dynamical Systems

The paper addresses the realization and identification problem or a subclass of piecewise-affine hybrid systems. The paper provides necessary and sufficient conditions for existence of a realization, a characterization of minimality, and an identification algorithm for this subclass of hybrid systems. The considered system class and the identification problem are motivated by applications in systems biology

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

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

S-Wave Quarkonia in Potential Models

We discuss S-wave quarkonia correlators and spectral function using the Wong-potential, and show that these do not agree with the lattice results.Comment: based on talk presented at Strangeness in Quark Matter, UCLA, March 26-31, 200

QCD thermodynamics from 3d adjoint Higgs model

The screening masses of hot SU(N) gauge theory, defined as poles of the corresponding propagators are studied in 3d adjoint Higgs model, considered as an effective theory of QCD, using coupled gap equations and lattice Monte-Carlo simulations (for N=2). Using so-called lambda gauges non-perturbative evidence for gauge independence of the pole masses within this class of gauges is given. A possible application of the screening masses for the resummation of the free energy is discussed.Comment: Talk given at the 5th International Workshop on Thermal Field Theory and their Applications, Regensburg (Germany), August 1998, corrected typo

Quarkonium in Hot Medium

I review recent progress in studying quarkonium properties in hot medium as well as possible consequences for quarkonium production in heavy ion collisions.Comment: Invited talk at SQM 2009, Buzios, Brazil, Sep. 27 -Oct. 2 2009, LaTeX, 8 pages,3 figures; typos corrected, references adde

Excited hadrons as a signal for quark-gluon plasma formation

At the quark-hadron transition, when quarks get confined to hadrons, certain orbitally excited states, namely those which have excitation energies above the respective $L = 0$ states of the same order as the transition temperature $T_c$, may form easily because of thermal velocities of quarks at the transition temperature. We propose that the ratio of multiplicities of such excited states to the respective $L = 0$ states can serve as an almost model independent signal for the quark-gluon plasma formation in relativistic heavy-ion collisions. For example, the ratio $R^*$ of multiplicities of $D_{SJ}^{*\pm}(2317)(J^P = 0^+)$ and $D_S^{*\pm}(2112)(J^P = 1^-)$ when plotted with respect to the center of mass energy of the collision $\sqrt{s}$ (or vs. centrality/number of participants), should show a jump at the value of $\sqrt{s}$ beyond which the QGP formation occurs. This should happen irrespective of the shape of the overall plot of $R^*$ vs. $\sqrt{s}$. Recent data from RHIC on $\Lambda^*/\Lambda$ vs. N$_{part}$ for large values of N$_{part}$ may be indicative of such a behavior, though there are large error bars. We give a list of several other such candidate hadronic states.Comment: 19 pages, RevTex, no figures, minor change

Realization Theory of Hybrid Systems

The thesis address the realization problem for hybrid control systems. It develops realization theory for a number of classes of hybrid systems.Schuppen, J.H. van [Promotor