摘要:

I review Klaus Kinder-Geiger’s contributions to the physics of relativistic heavy ion collisions, in particular, the Parton Cascade Model. Klaus developed this model in order to provide a QCD–based description of nucleus-nucleus reactions at high energies such as they will soon become available at the Brookhaven Relativistic Heavy Ion Collider. The PCM describes the collision dynamics within the early and dense phase of the reaction in terms of the relativistic, probabilistic transport of perturbative excitations (partons) of the QCD vacuum. I will present an overview of the current state of the numerical implementations of this model, as well as its predictions for nuclear collisions at RHIC and LHC. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.59571

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

A schematic two-level model consisting of a “collective” bosonic state and an “elementary” meson is constructed that provides interpolation from a hadronic description (a la Rapp/Wambach) to B/R scaling for the description of properties of vector mesons in dense medium. The development is based on a close analogy to the degenerate schematic model of Brown for giant resonances in nuclei. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.59570

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

Recent developments linking non-perturbative quantum gauge theories in Minkowski space to classical gravity theories in anti-de-Sitter space are reviewed at a simple level. It is suggested how these spectacular advances may be extended to discuss the quark-gluon phase transition in terms of black holes in anti-de-Sitter space, with possible relevance to heavy-ion collisions. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.59572

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

We show that the distributions of outgoing protons and charged hadrons in high energy proton-nucleus collisions are described rather well by a linear extrapolation from proton-proton collisions. The only adjustable parameter required is the shift in rapidity of a produced charged meson when it encounters a target nucleon. Its fitted value is 0.16. Next, we apply this linear extrapolation to precisely measured Drell-Yan cross sections for 800 GeV protons incident on a variety of nuclear targets which exhibit a deviation from linear scaling in the atomic numberA. We show that this deviation can be accounted for by energy degradation of the proton as it passes through the nucleus if account is taken of the time delay of particle production due to quantum coherence. We infer an average proper coherence time of0.4±0.1&hthinsp;fm/c,corresponding to a coherence path length of8±2&hthinsp;fmin the rest frame of the nucleus. Finally, we apply the linear extrapolation to measuredJ/&psgr;production cross sections for 200 and 450 GeV/c protons incident on a variety of nuclear targets. Our analysis takes into account energy loss of the beam proton, the time delay of particle production due to quantum coherence, and absorption of theJ/&psgr;on nucleons. The best representation is obtained for a coherence time of 0.5 fm/c, which is consistent with Drell-Yan production, and an absorption cross section of 3.6 mb, which is consistent with the value deduced from photoproduction of theJ/&psgr;on nuclear targets. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.59575

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

We report on work done in collaboration with Klaus Kinder-Geiger and John Ellis which aims at connecting the space-time structure of event generator simulations with observable output. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.59573

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

A method for determining the presence of partonic scattering through two-particle correlations is developed and applied to models which have jets and mini-jets in them. We only consider the correlation of mid-rapidity particles because they will be easily measured in large numbers at RHIC. The level of two-particle correlations will be a direct measure of how dense a system is made in Au-Au collisions at RHIC. The STAR TPC will be ideal for making these measurements in the first year of running. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.59574

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

I discuss the initial conditions for a parton cascade. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.59567

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

We study the importance of the partonic phase produced in relativistic heavy ion collision by comparing the parton cascade model and the hadronic cascade model. Hadron yield, baryon stopping and transverse momentum distribution are calculated with JAM and discussions are given comparing with VNI. Both of these models give good description of experimental data. We also discuss the strangeness production mechanism and the directed transverse flow. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.59568

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

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, includingJ/&PSgr;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. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.59576

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

We briefly recall the tremendous strides in the studies of the parton cascade model made by Klaus Geiger. Next, we argue that photons may provide confirmation of several of these ideas. Thus we know that, copious internetted partonic cascades may develop in the wake of relativistic collisions of nuclei at CERN SPS and BNL RHIC energies, We use the parton cascade model to estimate the emission of single photons generated from such cascades due to the branching of quarksq→q&ggr;,scattering of quarks and gluons, and annihilation of quarks. The formation of a hot and dense partonic matter is shown to be preceded by an intense radiation of photons from the QED branching of quarks. This is similar to the QCD branchingq→qgwhich along with the gluon multiplication(g→gg)which is known to play a crucial role in the formation of the dense partonic plasma. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.59569

出版商:AIP    

年代:1999

数据来源: AIP