QGP Formation and Strange Antibaryons

We analyze current experimental results and explore, as function of the collision energy and stopping in relativistic nuclear collisions, the production yields of strange antibaryons, assuming formation of a deconfined thermal QGP-fireball which undergoes a sudden hadronisation.Comment: Replaced by the published version. 11 pages, 3 figure

Strange Antibaryons from QGP

We study as function of the collision energy and stopping the thermal conditions reached in a quark-gluon plasma fireball formed in a relativistic heavy ion collision. We explore strange particle yields for the current round of Pb-Pb and Au-Au experiments.Comment: 4 pages, LaTeX, 3 postscript figures, Presented at Quark Matter 1995, Montere

Hot hadronic matter and strange anti-baryons

We demonstrate that both quark-gluon plasma (QGP) and hadronic gas (HG) models of the central fireball created in S -> W collisions at 200 GeV A are possible sources of the recently observed strange (anti-) baryons. From the theoretical point of view, the HG interpretation we attempt remains more obscure because of the high fireball temperature required. The thermal properties of the fireball as determined by the particle ratios, are natural for the QGP state. We show that the total particle multiplicity emerging from the central rapidity region allows to distinguish between the two scenarios.Comment: 10 pages, LaTeX, 1 postscript figure

Centrality dependence of strangeness and (anti)hyperon production at BNL RHIC

We evaluate strangeness produced in Au--Au interactions at $\sqrt{s_{\rm NN}}=200$ GeV, as function of reaction participant number $A$, and obtain the relative strange quark content at hadronization. Strange baryon and antibaryon rapidity density yields are studied, relative to, and as function of, participant number, and produced hadron yields.Comment: 4 pages including 4 figures, v2 text improvmen

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

Measurement of the Lorentz-FitzGerald Body Contraction

A complete foundational discussion of acceleration in context of Special Relativity is presented. Acceleration allows the measurement of a Lorentz-FitzGerald body contraction created. It is argued that in the back scattering of a probing laser beam from a relativistic flying electron cloud mirror generated by an ultra-intense laser pulse, a first measurement of a Lorentz-FitzGerald body contraction is feasible.Comment: 4 pages Letter, submitted to EPJA, dedicated to memory of Walter Greine

Strangeness and Quark--Gluon Plasma

I review the foundational motivation which led us to the ultra relativistic heavy ion collision research at SPS, RHIC and now LHC: the quantum vacuum structure; the deconfined nature of quark-gluon plasma (QGP) phase filling the Universe for the first 30$\mu$s after the big-bang; the origin of stable matter mass; and of the origin of flavor. The special role of strangeness enhancement and strange antibaryon signature is highlighted. It is shown how hadron production can be used to determine the properties of QGP, and how the threshold energy for QGP formation is determined.Comment: Jubilee Lecture at SQM2011 in Krakow, Poland to appear in Acta Physica Polonica

Strange Particle Abundance in QGP Formed in 200 GeV A Nuclear Collisions

We investigate here the relative abundance of strange particles produced in nuclear collisions at the SPS energies (9 GeV A in CM frame) assuming that the central reaction fireball consists of quark-gluon plasma. We show that the total strangeness yield in S-S, S-Ag and S-W reactions is compatible with this picture.Comment: 11 pages, LaTeX, 3 postscript figures, Phys. Lett. B 323 (1994) 39