OPUS 4 | Search

Elliptic flow analysis at RHIC with the Lee-Yang Zeroes method in a relativistic transport approach (2006)

Xianglei Zhu Marcus Bleicher Horst Stöcker

The Lee-Yang zeroes method is applied to study elliptic flow (v_2) in Au+Au collisions at sqrt s =200 A GeV, with the UrQMD model. In this transport approach, the true event plane is known and both the nonflow effects and event-by-event v_2 fluctuations exist. Although the low resolutions prohibit the application of the method for most central and peripheral collisions, the integral and differential elliptic flow from the Lee-Yang zeroes method agrees with the exact v_2 values very well for semi-central collisions.

DD correlations as a sensitive probe for thermalization in high-energy nuclear collisions (2006)

Xianglei Zhu Marcus Bleicher Shengli Huang Kai Oliver Schweda Horst Stöcker Hermine K. Wöhri Nu Xu Pengfei Zhuang

We propose to measure correlations of heavy-flavor hadrons to address the status of thermalization at the partonic stage of light quarks and gluons in high-energy nuclear collisions, shown on the example of azimuthal correlations of D-Dbar pairs. We show that hadronic interactions at the late stage can not disturb these correlations significantly. Thus, a decrease or the complete absence of these initial correlations indicates frequent interactions of heavy-flavor quarks in the partonic stage. Therefore, early thermalization of light quarks is likely to be reached. PACS numbers: 25.75.-q

Gravitational radiation from elastic particle scattering in models with extra dimensions (2005)

Benjamin Koch Marcus Bleicher

In this paper we derive a formula for the energy loss due to elastic N to N particle scattering in models with extra dimensions that are compactified on a radius R. In contrast to a previous derivation we also calculate additional terms that are suppressed by factors of frequency over compactification radius. In the limit of a large compactification radius R those terms vanish and the standard result for the non compactified case is recovered.

Transport model analysis of femtoscopy data at RHIC energies (2006)

Qingfeng Li Marcus Bleicher Horst Stöcker

The pion source as seen through HBT correlations at RHIC energies is investigated within the UrQMD approach. We find that the calculated transverse momentum, centrality, and system size dependence of the Pratt-HBT radii R_L and R_S are reasonably well in line with experimental data. The predicted R_O values in central heavy ion collisions are larger as compared to experimental data. The corresponding quantity sqrt R_O^2-R_S^2 of the pion emission source is somewhat larger than experimental estimates.

Gravitational radiation from ultra high energy cosmic rays in models with large extra dimensions (2006)

Benjamin Koch Hans-Joachim Drescher Marcus Bleicher

The effects of classical gravitational radiation in models with large extra dimensions are investigated for ultra high energy cosmic rays (CRs). The cross sections are implemented into a simulation package (SENECA) for high energy hadron induced CR air showers. We predict that gravitational radiation from quasi-elastic scattering could be observed at incident CR energies above 10^9 GeV for a setting with more than two extra dimensions. It is further shown that this gravitational energy loss can alter the energy reconstruction for CR energies E_CR > 5 10^9 GeV.

No black holes at IceCube (2006)

Ulrich Harbach Marcus Bleicher

We discuss modifications of the neutrino-nucleon cross section due to a minimal length scale. It is shown that the enhancement of the nu-N cross section due to new physics is suppressed. Especially the potential observation rate of micro black holes at neutrino telescopes is strongly reduced.

The origin of transverse flow at the SPS (1998)

Marcus Bleicher Christian Spieles Christoph Ernst Lars Gerland Sven Soff Horst Stöcker Walter Greiner Steffen A. Bass

We study the transverse expansion in central Pb+Pb collisions at the CERN SPS. Strong collective motion of hadrons can be created. This flow is mainly due to meson baryon rescattering. It allows to study the angular distribution of intermediate mass meson baryon interactions.

Antibaryons in massive heavy ion reactions : importance of potentials (1995)

Christian Spieles Marcus Bleicher André Jahns Raffaele Mattiello Heinz Sorge Horst Stöcker Walter Greiner

In the framework of RQMD we investigate antiproton observables in massive heavy ion collisions at AGS energies and compare to preliminary results of the E878 collaboration. We focus here on the considerable influence of the real part of an antinucleon nucleus optical potential on the ¯p momentum spectra. Pacs-numbers: 14.20 Dh, 25.70.-z

Phasespace Correlations of Antideuterons in Heavy Ion Collisions (1995)

Marcus Bleicher Christian Spieles André Jahns Raffaele Mattiello Heinz Sorge Horst Stöcker Walter Greiner

In the framework of the relativistic quantum molecular dynamics approach (RQMD) we investigate antideuteron (d) observables in Au+Au collisions at 10.7 AGeV. The impact parameter dependence of the formation ratios d/p2 and d/p2 is calculated. In central collisions, the antideuteron formation ratio is predicted to be two orders of magnitude lower than the deuteron formation ratio. The d yield in central Au+Au collisions is one order of magnitude lower than in Si+Al collisions. In semicentral collisions di erent configuration space distributions of p s and d s lead to a large squeeze out e ect for antideuterons, which is not predicted for the p s.

Hypermatter : properties and formation in relativistic nuclear collisions (1995)

Lars Gerland Christian Spieles Marcus Bleicher Panajotis Papazoglou Jörg Brachmann Adrian Dumitru Horst Stöcker Walter Greiner Jürgen Schaffner Carsten Greiner

The extension of the Periodic System into hitherto unexplored domains - anti- matter and hypermatter - is discussed. Starting from an analysis of hyperon and single hypernuclear properties we investigate the structure of multi-hyperon objects (MEMOs) using an extended relativistic meson field theory. These are contrasted with multi-strange quark states (strangelets). Their production mechanism is stud- ied for relativistic collisions of heavy ions from present day experiments at AGS and SPS to future opportunities at RHIC and LHC. It is pointed out that abso- lutely stable hypermatter is unlikely to be produced in heavy ion collisions. New attention should be focused on short lived metastable hyperclusters ( / 10 10s) and on intensity interferometry of multi-strange-baryon correlations.

Refine

Author

Year of publication

Document Type

Language

Keywords

Institute

124 search hits