Hadronic correlations above the chiral/deconfinement transition

The statistical bootstrap model is critically revised in order to include a medium-dependent resonance width in it. We show that a thermodynamic model with a vanishing width below the Hagedorn temperature T_H and a Hagedorn spectrum-like width above T_H may not only eliminate the divergence of the thermodynamic functions above T_H, but also gives a satisfactory description the lattice quantum chromodynamics (QCD) data on the energy density above the chiral/deconfinement transition as the main result of this contribution. This model allows to explain the absence of heavy resonance contributions in the fit of the experimentally measured particle ratios at SPS and RHIC energies.Comment: 9 pages, 2 figures, contribution to proceedings of NAPP 2003, Dubrovnik, Croatia, 26-31 May, 200

Nonlocality effects on spin-one pairing patterns in two-flavor color superconducting quark matter and compact stars applications

We study the influence of nonlocality in the interaction on two spin one pairing patterns of two-flavor quark matter: the anisotropic blue color paring besides the usual two color superconducting matter (2SCb), in which red and green colors are paired, and the color spin locking phase (CSL). The effect of nonlocality on the gaps is rather large and the pairings exhibit a strong dependence on the form factor of the interaction, especially in the low density region. The application of these small spin-one condensates for compact stars is analyzed: the early onset of quark matter in the nonlocal models may help to stabilize hybrid star configurations. While the anisotropic blue quark pairing does not survive a big asymmetry in flavor space as imposed by the charge neutrality condition, the CSL phase as a flavor independent pairing can be realized as neutral matter in compact star cores. However, smooth form factors and the missmatch between the flavor chemical potential in neutral matter make the effective gaps of the order of magnitude $\simeq 10$ keV, and a more systematic analysis is needed to decide whether such small gaps could be consistent with the cooling phenomenology.Comment: 18 pages, 7 figures, corrected version with revised parameterizatio

Mott effect at the chiral phase transition and anomalous J/Psi suppression

We investigate the in-medium modification of the charmonium break-up processes due to the Mott effect for light (pi) and open-charm (D, D*) mesons at the chiral/deconfinement phase transition. A model calculation for the process J/Psi + pi -> D + \bar D* + h.c. is presented which demonstrates that the Mott effect for the D-mesons leads to a threshold effect in the thermal averaged break-up cross section. This effect is suggested as an explanation of the phenomenon of anomalous J/Psi suppression in the CERN NA50 experiment.Comment: 9 pages, 3 figures; final version to appear in Phys. Lett.

Color neutrality effects in the phase diagram of the PNJL model

The phase diagram of a two-flavor Polyakov loop Nambu-Jona-Lasinio model is analyzed imposing the constraint of color charge neutrality. Main effects of this constraint are a shrinking of the chiral symmetry breaking (chiSB) domain in the T-mu plane, a shift of the critical point to lower temperatures and a coexistence of chiSB and two-flavor superconducting phases. The effects can be understood in view of the presence of a nonvanishing color chemical potential mu_8, which is necessary to compensate the color charge density rho_8 induced by the nonvanishing Polyakov-loop mean field phi_3.Comment: 8 pages, 4 figures, figures added, minor text modification

Accessibility of color superconducting quark matter phases in heavy-ion collisions

We discuss a hybrid equation of state (EoS) that fulfills constraints for mass-radius relationships and cooling of compact stars. The quark matter EoS is obtained from a Polyakov-loop Nambu--Jona-Lasinio (PNJL) model with color superconductivity, and the hadronic one from a relativistic mean-field (RMF) model with density-dependent couplings (DD-RMF). For the construction of the phase transition regions we employ here for simplicity a Maxwell construction. We present the phase diagram for symmetric matter which exhibits two remarkable features: (1) a "nose"-like structure of the hadronic-to-quark matter phase border with an increase of the critical density at temperatures below T ~ 150 MeV and (2) a high critical temperature for the border of the two-flavor color superconducting (2SC) phase, T_c > 160 MeV. We show the trajectories of heavy-ion collisions in the plane of excitation energy vs. baryon density calculated using the UrQMD code and conjecture that for incident energies of 4 ... 8 A GeV as provided, e.g., by the Nuclotron-M at JINR Dubna or by lowest energies at the future heavy-ion collision experiments CBM@FAIR and NICA@JINR, the color superconducting quark matter phase becomes accessible.Comment: 5 pages, 1 figure, Poster presented at the XXVI. Max Born Symposium "Three Days of Strong Interactions", Wroclaw (Poland), July 9-11, 200

Heavy flavor kinetics at the hadronization transition

We investigate the in-medium modification of the charmonium breakup processes due to the Mott effect for light (pi, rho) and open-charm (D, D*) quark-antiquark bound states at the chiral/deconfinement phase transition. The Mott effect for the D-mesons effectively reduces the threshold for charmonium breakup cross sections, which is suggested as an explanation of the anomalous J/psi suppression phenomenon in the NA50 experiment. Further implications of finite-temperature mesonic correlations for the hadronization of heavy flavors in heavy-ion collisions are discussed.Comment: 4 pages, 2 figures, Contribution to SQM2001 Conference, submitted to J. Phys.

Conformal relativity versus Brans-Dicke and superstring theories

Conformal relativity theory which is also known as Hoyle-Narlikar theory has recently been given some new interest. It is an extended relativity theory which is invariant with respect to conformal transformations of the metric. In this paper we show how conformal relativity is related to the Brans-Dicke theory and to the low-energy-effective superstring theory. We show that conformal relativity action is equaivalent to a transformed Brans-Dicke action for Brans-Dicke parameter $\omega = -3/2$ in contrast to a reduced (graviton-dilaton) low-energy-effective superstring action which corresponds to a Brans-Dicke action with Brans-Dicke parameter $\omega = -1$. In fact, Brans-Dicke parameter $\omega =-3/2$ gives a border between a standard scalar field evolution and a ghost. We also present basic cosmological solutions of conformal relativity in both Einstein and string frames. The Eintein limit for flat conformal cosmology solutions is unique and it is flat Minkowski space. This requires the scalar field/mass evolution instead of the scale factor evolution in order to explain cosmological redshift. It is interesting that like in ekpyrotic/cyclic models, a possible transition through a singularity in conformal cosmology in the string frame takes place in the weak coupling regime.Comment: REVTEX4, 12 pages, an improved version, references adde