Latest documents http://publikationen.stub.uni-frankfurt.de/index/index/ Tue, 12 Jul 2005 10:33:38 +0100 Tue, 12 Jul 2005 10:33:38 +0100 http://publikationen.stub.uni-frankfurt.de/frontdoor/index/index/docId/3110 Noneequilibrium models (three-fluid hydrodynamics and UrQMD) use to discuss the uniqueness of often proposed experimental signatures for quark matter formation in relativistic heavy ion collisions. It is demonstrated that these two models - although they do treat the most interesting early phase of the collisions quite differently(thermalizing QGP vs. coherent color fields with virtual particles) - both yields a reasonable agreement with a large variety of the available heavy ion data. Stefan Scherer; Steffen A. Bass; Marcus Bleicher; Mohamed Belkacem; Larissa V. Bravina; Jörg Brachmann; Adrian Dumitru; Christoph Ernst; Lars Gerland; Markus Hofmann; Ludwig Neise; Manuel Reiter; Sven Soff; Christian Spieles; Henning Weber; Eugene E. Zabrodin; Detlef Zschiesche; Joachim A. Maruhn; Horst Stöcker; Walter Greiner article http://publikationen.stub.uni-frankfurt.de/frontdoor/index/index/docId/3110 Wed, 07 Dec 2005 10:33:38 +0100 http://publikationen.stub.uni-frankfurt.de/frontdoor/index/index/docId/3132 We investigate the hadronic cooling of a quark droplet within a microscopic model. The color flux tube approach is used to describe the hadronization of the quark phase. The model reproduces experimental particle ratios equally well compared to a static thermal hadronic source. Furthermore, the dynamics of the decomposition of a quark-gluon plasma is investigated and time dependent particle ratios are found. Markus Hofmann; Judah M. Eisenberg; Stefan Scherer; Marcus Bleicher; Ludwig Neise; Horst Stöcker; Walter Greiner preprint http://publikationen.stub.uni-frankfurt.de/frontdoor/index/index/docId/3132 Thu, 01 Dec 2005 10:24:26 +0100 http://publikationen.stub.uni-frankfurt.de/frontdoor/index/index/docId/3155 A microscopic model of deconfined matter based on color interactions between semi-classical quarks is studied. A hadronization mechanism is imposed to examine the properties and the disassembly of a thermalized quark plasma and to investigate the possible existence of a phase transition from quark matter to hadron matter. M. Hofmann; Marcus Bleicher; Stefan Scherer; Ludwig Neise; Horst Stöcker; Walter Greiner preprint http://publikationen.stub.uni-frankfurt.de/frontdoor/index/index/docId/3155 Thu, 24 Nov 2005 10:58:21 +0100 http://publikationen.stub.uni-frankfurt.de/frontdoor/index/index/docId/3255 The quark-molecular-dynamics model is used to study microscopically the dynamics of the coloured quark phase and the subsequent hadron formation in relativistic S+Au collisions at the CERN-SPS. Particle spectra and hadron ratios are compared to both data and the results of hadronic transport calculations. The non-equilibrium dynamics of hadronization and the loss of correlation among quarks are studied. Stefan Scherer; Markus Hofmann; Marcus Bleicher; Ludwig Neise; Horst Stöcker; Walter Greiner preprint http://publikationen.stub.uni-frankfurt.de/frontdoor/index/index/docId/3255 Fri, 18 Nov 2005 12:50:11 +0100 http://publikationen.stub.uni-frankfurt.de/frontdoor/index/index/docId/3297 Abstract Geant4 is a toolkit for simulating the passage of particles through matter. It includes a complete range of functionality including tracking, geometry, physics models and hits. The physics processes offered cover a comprehensive range, including electromagnetic, hadronic and optical processes, a large set of long-lived particles, materials and elements, over a wide energy range starting, in some cases, from 250 eV and extending in others to the TeV energy range. It has been designed and constructed to expose the physics models utilised, to handle complex geometries, and to enable its easy adaptation for optimal use in different sets of applications. The toolkit is the result of a worldwide collaboration of physicists and software engineers. It has been created exploiting software engineering and object-oriented technology and implemented in the C++ programming language. It has been used in applications in particle physics, nuclear physics, accelerator design, space engineering and medical physics. PACS: 07.05.Tp; 13; 23 S. Agostinelli; Dennis Dean Dietrich; Walter Greiner; Kerstin Anja Paech; Stefan Scherer; Horst Stöcker; Henning Weber; Detlef Zschiesche; et al.; Geant4 Collaboration article http://publikationen.stub.uni-frankfurt.de/frontdoor/index/index/docId/3297 Wed, 16 Nov 2005 09:44:27 +0100 http://publikationen.stub.uni-frankfurt.de/frontdoor/index/index/docId/3367 Nonequilibrium models (three-fluid hydrodynamics, UrQMD, and quark molecular dynamics) are used to discuss the uniqueness of often proposed experimental signatures for quark matter formation in relativistic heavy ion collisions from the SPS via RHIC to LHC. It is demonstrated that these models - although they do treat the most interesting early phase of the collisions quite differently (thermalizing QGP vs. coherent color fields with virtual particles) -- all yield a reasonable agreement with a large variety of the available heavy ion data. Hadron/hyperon yields, including J/Psi meson production/suppression, strange matter formation, dileptons, and directed flow (bounce-off and squeeze-out) are investigated. Observations of interesting phenomena in dense matter are reported. However, we emphasize the need for systematic future measurements to search for simultaneous irregularities in the excitation functions of several observables in order to come close to pinning the properties of hot, dense QCD matter from data. The role of future experiments with the STAR and ALICE detectors is pointed out. Stefan Scherer; Steffen A. Bass; Mohamed Belkacem; Marcus Bleicher; Jörg Brachmann; Adrian Dumitru; Christoph Ernst; Lars Gerland; Nils Hammon; Markus Hofmann; Jens Konopka; Ludwig Neise; Manuel Reiter; Stefan Schramm; Sven Soff; Christian Spieles; Henning Weber; Detlef Zschiesche; Joachim A. Maruhn; Horst Stöcker; Walter Greiner preprint http://publikationen.stub.uni-frankfurt.de/frontdoor/index/index/docId/3367 Tue, 01 Nov 2005 09:26:33 +0100 http://publikationen.stub.uni-frankfurt.de/frontdoor/index/index/docId/4784 Compelling evidence for the creation of a new form of matter has been claimed to be found in Pb+Pb collisions at SPS. We discuss the uniqueness of often proposed experimental signatures for quark matter formation in relativistic heavy ion collisions. It is demonstrated that so far none of the proposed signals like J/psi meson production/suppression, strangeness enhancement, dileptons, and directed flow unambigiously show that a phase of deconfined matter has been formed in SPS Pb+Pb collisions. We emphasize the need for systematic future measurements to search for simultaneous irregularities in the excitation functions of several observables in order to come close to pinning the properties of hot, dense QCD matter from data. Detlef Zschiesche; Steffen A. Bass; Marcus Bleicher; Jörg Brachmann; Lars Gerland; Kerstin Paech; Stefan Scherer; Sven Soff; Christian Spieles; Henning Weber; Horst Stöcker; Walter Greiner preprint http://publikationen.stub.uni-frankfurt.de/frontdoor/index/index/docId/4784 Thu, 14 Apr 2005 16:28:30 +0200