Strangeness enhancement and Energy dependence in Heavy Ion Collisions

The canonical statistical model analysis of strange and multistrange hadron production in central A-A relative to p-p/p-A collisions is presented over the energy range from $\sqrt s=8.73$ GeV up to $\sqrt s =130$ GeV. It is shown that the relative enhancement of strange particle yields from p-p/p-A to A-A collisions substantially increases with decreasing collision energy. It is largest at $\sqrt s= 8.7$ GeV, where the enhancement of $\Omega,\Xi$ and $\Lambda$ is of the order of 100, 20 and 3, respectively. In terms of the model these results are due to the canonical suppression of particle thermal phase space at lower energies, which increases with the strangeness content of the particle and with decreasing size of the collision fireball. The comparison of the model with existing data on energy dependence of the kaon/pion ratio is also discussed

The canonical effect in statistical models for relativistic heavy ion collisions

Enforcing exact conservation laws instead of average ones in statistical thermal models for relativistic heavy ion reactions gives raise to so called canonical effect, which can be used to explain some enhancement effects when going from elementary (e.g. pp) or small (pA) systems towards large AA systems. We review the recently developed method for computation of canonical statistical thermodynamics, and give an insight when this is needed in analysis of experimental data.Comment: 4 pages, 3 figures. Talk given in Strangeness in Quark Matter, Frankfurt am Main 2001. Submitted to J. Phys. G: Nucl. Part. Phy

Group projection method in statistical systems

We discuss an application of group theoretical methods to the formulation of the thermodynamics of systems constrained by the conservation laws described by a semi--simple compact Lie group. A general projection method that allows to construct a partition function for a given irreducible representation of the Lie group is outlined. Applications of the method in Lattice Gauge Theory (LGT) for non--zero baryon number and in the phenomenological description of particle production in ultrarelativistic heavy ion collisions are also indicated.Comment: Invited talk presented at the XXIV International Colloquium on Group Theoritical Methods in Physic

Heavy ion collisions and lattice QCD at finite baryon density

We discuss a relation between the QCD thermodynamics obtained from a statistical analysis of particle production in heavy ion collisions at SPS and RHIC energies and recent LGT results at finite chemical potential. We show that basic thermodynamic properties obtained from the phenomenological statistical operator of a hadron resonance gas that describes particle yields in heavy ion collisions are consistent with recent LGT results. We argue that for $T\leq T_c$ the equation of state derived from Monte--Carlo simulations of two quark--flavor QCD at finite chemical potential can be well described by a hadron resonance gas when using the same set of approximations as used in LGT calculations. We examine the influence of a finite quark mass on the position of the deconfinement transition in temperature and chemical potential plane.Comment: To appear in the proceedings of 17in International Conference on Ultra Relativistic Nucleus-Nucleus Collisions (Quark Matter 2004), Oakland, California, 11-17 Jan 200

One Loop Effects in Various Dimensions and D-Branes

We calculate some one loop corrections to the effective action of theories in $d$ dimensions that arise on the dimensional reduction of a Weyl fermion in $D$ dimensions. The terms that we are interested in are of a topological nature. Special attention is given to the effective actions of the super Yang Mills theories that arise on dimensional reduction of the N=1 theory in six dimensions or on the dimensional reduction of the N=1 theory in ten dimensions. In the latter case we suggest an interpretation of the quantum effect as a coupling of the gauge field on the brane to a relative background gauge field.Comment: 18 pages, LaTe

Conservation Laws and Particle Production in Heavy Ion Collisions

We discuss the role of the conservation laws related with U(1) internal symmetry group in the statistical model description of particle productions in ultrarelativistic heavy ion collisions. We derive and show the differences in particle multiplicities in the canonical and the grand canonical formulation of quantum number conservation. The time evolution and the approach to chemical equilibrium in the above ensembles is discussed in terms of kinetic master equation. The application of the statistical model to the description of (multi)strange particle yields at GSI/SIS and the SPS energies is also presented.Comment: Invited talk at International Symposium on Hadron and Nuclei, Seoul, Korea, 20-22 Feb 200

The statistical model in Pb-Pb collisions at the LHC

We briefly review the predictions of the thermal model for hadron production in comparison to latest data from RHIC and extrapolate the calculations to LHC energy. Our main emphasis is to confront the model predictions with the recently released data from ALICE at the LHC. This comparison reveals an apparent anomaly for protons and anti-protons which we discuss briefly. We also demonstrate that our statistical hadronization predictions for J/$\psi$ production agree very well with the most recent LHC data, lending support to the picture in which there is complete charmonium melting in the quark-gluon plasma (QGP) followed by statistical generation of J/$\psi$ mesons at the phase boundary.Comment: 4 pages, 3 figures, proceedings of QM201