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# Search results

156 records were found.

## Is the existence of a softest point in the directed flow excitation function an unambiguous signal for the creation of a quark gluon plasma?

We investigate the claim that a minimum of the excitation function of the in-plane directed flow of nucleons in ultrarelativistic heavy-ion collisions is a ‘smoking gun' signature for the creation of a quark–gluon plasma (QGP). Employing a non-equilibrium transport approach we demonstrate that such a minimum is expected in heavy ion collisions and not related to the formation of a QGP. The minimum has its origin in the interplay between a decreasing scattering angle of the elastic collisions with increasing beam energy, which lowers the in-plane flow, and the onset of particle production which increases the in-plane flow. Thus, the interpretation of this minimum as a ‘smoking gun' signature for the creation of a QGP seems premature.

## Core-corona separation in the UrQMD hybrid model

Comment: 10 pages, 11 figures, version accepted by PRC

## Anisotropic flow in ultra-relativistic heavy ion collisions

A sign reversal of the directed flow parameter $v_1$ in the central rapidity region in Au+Au collisions at $\sqrt s =200$~AGeV is predicted. This anti-flow is shown to be linked to the expansion of the hot matter created. In line with this observation the predicted elliptic flow parameter $v_2$ of various particle species is predicted and linked to the mean free path of these particles.

## Resonance Production in Heavy Ion Collisions - what can we learn from RHIC?

Comment: Proceedings of the 22nd Winter Workshop on Nuclear Dynamics

## Gravitational radiation from elastic particle scattering in models with extra dimensions

Comment: 17 pages

## Longitudinal flow and onset of deconfinement

Comment: Proceedings of the 3rd International Workshop The Critical Point and Onset of Deconfinement, Firenze, Italy

## Non-thermal $p/\pi$ ratio at LHC as a consequence of hadronic final state interactions

Recent LHC data on Pb+Pb reactions at sqrt s_{NN}=2.7 TeV suggests that the p/pi is incompatible with thermal models. We explore several hadron ratios (K/pi, p/pi, Lambda/pi, Xi/pi) within a hydrodynamic model with hadronic after burner, namely UrQMD 3.3, and show that the deviations can be understood as a final state effect. The measured values of the hadron ratios do then allow to gauge the transition energy density from hydrodynamics to the Boltzmann description. We find that the data can be explained with transition energy densities of 840 +- 150 MeV/fm^3.

## Resonances as a possible observable of hot and dense nuclear matter

One of the most fundamental questions in the field of relativistic heavy ion physics is how to reach and explore densities which are needed to cross the chiral and/or the deconfinement phase transition. In this analysis we investigate the information we can gather by analyzing baryonic and mesonic resonances on the hot and dense phase in such nuclear reactions. The decay products of these resonances carry information on the resonances properties at the space time point of their decay. We especially investigate the percentage of reconstructable resonances as a function of density for heavy ion collisions in the energy range between $E_{lab}$ = 30 AGeV and $\sqrt{s}$ = 200 AGeV, the energy domain between the future FAIR facility and the present RHIC collider.

## High $p_T$ resonances as a possibility to explore hot and dense nuclear matter

One of the fundamental objectives of experiments with ultrarelativistic heavy ions is to explore strongly interacting matter at high density and high temperature. In this investigation we study in particular the information which can be obtained by analyzing baryonic and mesonic resonances. The decay products of these resonances carry information on the resonances properties at the space time point of their decay. We especially investigate the percentage of reconstructable resonances as a function of density for heavy ion collisions in the energy range between $E_{lab}$ = 30 AGeV and $\sqrt{s}$ = 200 AGeV, the energy domain between the future FAIR facility and the present RHIC collider.