Non-equilibrium Hadrochemistry in QGP Hadronization

This survey offers an introductory tutorial for students of any age of the currently thriving field of hadrochemistry. We discuss the different chemical potentials, how the hadronic phase space is described and how one evaluates the abundance of hadrons at time of hadronization. We show that a rather accurate description of experimental data arises and we present results of fits to hadron yields at SPS and RHIC. We show that introduction of chemical non-equilibrium originating in a sudden hadronization of a QGP is favored strongly at SPS and is presently also emerging at RHIC. The low chemical freeze-out temperatures are consistent with the picture of single freeze-out scenario (chemical and thermal freeze-out coincide).Comment: To appear in the proceedings of Pan American Advanced Studies Institute on New States of Matter in Hadronic Interactions (PASI 2002), Campos do Jordao, Brazil, 7-18 Jan 2002; American Institute of Physics 2002 *v2 Contains UPDATED RHIC-130 chemical freeze-out analysis

Strangeness and Statistical QCD

We discuss properties of statistical QCD relevant in Fermi phase space model analysis of strange hadron production experimental data. We argue that the analysis results interpreted using established statistical QCD properties are demonstrating formation of the color deconfined state of matter in relativistic heavy ion collisions at highest CERN-SPS energies and at BNL-RHIC, comprising deconfined matter composed of nearly massless quarks and gluons, in statistical equilibrium.Comment: 22 pages, including 7 figures, 3 tables, to appear in Nuclear Physics Proceedings Supplement: STATISTICAL QCD, held at Bielefeld August 200

Strangeness and Statistical Hadronization: How to Study Quark-Gluon Plasma

Statistical hadronization is presented as mechanism for (strange) particle production from a deconfined quark--gluon plasma (QGP) fireball. We first consider hadronic resonance production at RHIC as a test of the model. We present in detail how the hadrochemistry determines particle multiplicities and in case of sudden hadronization allows investigation of QGP properties. A comparative study of strange hadron production at SPS and RHIC is presented. The energy dependence of physical observables shows regularities and a potential discontinuity in the low RHIC range, when comparing these different energy domains. Considering the energy scan program at CERN-SPS we show that the K^+/\pi^+ discontinuity is a baryon density effect.Comment: 35 pages, 15 figures, presented at the Cracow School of Theoretical Physics, Zakopane, May 30 - June 8, 200

Strangeness and thresholds of phase changes in relativistic heavy ion collisions

We discuss how the dynamics of the evolving hot fireball of quark--gluon matter impacts phase transition between the deconfined and confined state of matter. The rapid expansion of the fireball of deconfined matter created in heavy ion collisions facilitates formation of an over-saturated strange quark phase space. The related excess abundance of strangeness is compensating the suppression of this semi-heavy quark yield by its quark mass. In addition, the dynamical expansion of colored quanta pushes against the vacuum structure, with a resulting supercooling of the transition temperature. We address the status of the search for the phase boundary as function of reaction energy and collision centrality and show evidence for a change in reaction mechanism at sufficiently low energies. The phase diagram derived from the study of hadron production conditions shows two boundaries, one corresponding to the expected transition between confined and deconfined matter, with a downward temperature shift, and the other a high quark density hadronization which appears to involve heavy effective quarks, at relatively large temperatures.Comment: 10 Pages, presented at Workshop on Light-Cone QCD and Nonperturbative Hadron Physics 2005 (LC2005), Cairns, July 2005, to appear in proceeding

Probing Dense Matter with Strange Hadrons

Analysis of hadron production experimental data allows to understand the properties of the dense matter fireball produced in relativistic heavy ion collisions. We interpret the analysis results and argue that color deconfined state has been formed at highest CERN-SPS energies and at BNL-RHIC.Comment: 12 pages incl 1 figure, 3 table