2,451 research outputs found
Quark liberation and coalescence at CERN SPS
The mischievous linear coalescence approach to hadronization of quark matter
is shown to violate strangeness conservation in strong interactions. The
simplest correct quark counting is shown to coincide with the non-linear
algebraic coalescence rehadronization model, ALCOR. The non-linearity of the
ALCOR model is shown to cancel from its simple predictions for the relative
yields of (multi-)strange baryons. We prove, model independently, that quark
degrees of freedom are liberated before hadron formation in 158 AGeV central Pb
+ Pb collisions at CERN SPS.Comment: Latex file, 6 pages, improved text and conclusio
Observing Quark-Gluon Plasma with Strange Hadrons
We review the methods and results obtained in an analysis of the experimental
heavy ion collision research program at nuclear beam energy of 160-200A GeV. We
study strange, and more generally, hadronic particle production experimental
data. We discuss present expectations concerning how these observables will
perform at other collision energies. We also present the dynamical theory of
strangeness production and apply it to show that it agrees with available
experimental results. We describe strange hadron production from the
baryon-poor quark-gluon phase formed at much higher reaction energies, where
the abundance of strange baryons and antibaryons exceeds that of nonstrange
baryons and antibaryons.Comment: 39 journal pages (155kb text), 8 postscript figures, 8 table
Strange Messages: Chemical and Thermal Freeze-out in Nuclear Collisions
Thermal models are commonly used to interpret heavy-ion data on particle
yields and spectra and to extract the conditions of chemical and thermal
freeze-out in heavy-ion collisions. I discuss the usefulness and limitations of
such thermal model analyses and review the experimental and theoretical
evidence for thermalization in nuclear collisions. The crucial role of
correlating strangeness production data with single particle spectra and
two-particle correlation measurements is pointed out. A consistent dynamical
picture for the heavy-ion data from the CERN SPS involves an initial
prehadronic stage with deconfined color and with an appreciable isotropic
pressure component. This requires an early onset of thermalization.Comment: 15 pages, 2 figures, talk given at Strange Quark Matter '98, Padova,
Italy, 20-24 July 1998, to be published in J. Phys. G 25; final version with
updated reference
Clocking hadronization in relativistic heavy ion collisions with balance functions
A novel state of matter has been hypothesized to exist during the early stage
of relativistic heavy ion collisions, with normal hadrons not appearing until
several fm/c after the start of the reaction. To test this hypothesis,
correlations between charges and their associated anticharges are evaluated
with the use of balance functions. It is shown that late-stage hadronization is
characterized by tightly correlated charge/anticharge pairs when measured as a
function of relative rapidity.Comment: 5 pages, 3 figure
TELEMAC model archive: Integrating open–source tools for the management and visualisation of model data
Water Qualit
Strangeness enhancement from strong color fields at RHIC
In ultra-relativistic heavy ion collisions, early stage multiple scatterings
may lead to an increase of the color electric field strength. Consequently,
particle production - especially heavy quark (and di-quark) production - is
greatly enhanced according to the Schwinger mechanism. We test this idea via
the Ultra-relativistic Quantum Molecular Dynamics model (UrQMD) for Au+Au
collisions at the full RHIC energy ( AGeV). Relative to p+p
collisions, a factor of 60, 20 and 7 enhancement respectively, for
(), (), and , () is predicted for a model
with increased color electric field strength
Strange hyperon and antihyperon production from quark and string-rope matter
Hyperon and antihyperon production is investigated using two microscopical
models: {\bf (1)} the fast hadronization of quark matter as given by the ALCOR
model; {\bf (2)} string formation and fragmentation as in the HIJING/B model.
We calculate the particle numbers and momentum distributions for Pb+Pb
collisions at CERN SPS energies in order to compare the two models with each
other and with the available experimental data. We show that these two
theoretical approaches give similar yields for the hyperons, but strongly
differ for antihyperons.Comment: 11 pages, Latex, 3 EPS figures, contribution to the Proceedings of
the 4th International Conference on Strangeness in Quark Matter (SQM'98),
Padova, Italy, 20-24 July 199
- …