Competition of Heavy Quark Radiative and Collisional Energy Loss in Deconfined Matter

We extend our recently advanced model on collisional energy loss of heavy quarks in a quark gluon plasma (QGP) by including radiative energy loss. We discuss the approach and present first preliminary results. We show that present data on nuclear modification factor of non photonic single electrons hardly permit to distinguish between those 2 energy loss mechanisms.Comment: 8 pages, extended to 11 pages for v2; accepted for publication in Journal of Physics

Tomography of the Quark Gluon Plasma by Heavy Quarks

Using the recently published model \cite{Gossiaux:2008jv,goss2} for the collisional energy loss of heavy quarks in a Quark Gluon Plasma (QGP), based on perturbative QCD (pQCD), we study the centrality dependence of $R_{AA}$ and $R_{AA}(p_T^{min})$, %= \frac{dN_{AA}/dp_T}{ dN_{pp}/dp_T}$ measured by the Phenix collaboration, and compare our model with other approaches based on pQCD and on Anti de Sitter/ Conformal Field Theory (AdS/CFT)Comment: proceedings for SQM0

Clusters and Hypernuclei Production within PHQM+FRIGA Model

We present a new results on the dynamical modelling of cluster formation with the new combined PHQMD+FRIGA model at Nuclotron and NICA energies. The FRIGA clusterisation algorithm, which can be applied to the n-body transport approaches, is based on the simulated annealing technique to obtain the most bound configuration of fragments and nucleons. The PHQMD+FRIGA model is able to predict isotope yields as well as hyper-nucleus production

System Size Dependence of Particle Production at the SPS

Recent results on the system size dependence of net-baryon and hyperon production as measured at the CERN SPS are discussed. The observed Npart dependences of yields, but also of dynamical properties, such as average transverse momenta, can be described in the context of the core corona approach. Other observables, such as antiproton yields and net-protons at forward rapidities, do not follow the predictions of this model. Possible implications for a search for a critical point in the QCD phase diagram are discussed. Event-by-event fluctuations of the relative core to corona source contributions might influence fluctuation observables (e.g. multiplicity fluctuations). The magnitude of this effect is investigated.Comment: 10 pages, 4 figurs. Proceedings of the 6th International Workshop on Critical Point and Onset of Deconfinement in Dubna, Aug. 201

Cluster formation near midrapidity -- can the mechanism be identified experimentally?

The formation of weakly bound clusters in the hot and dense environment at midrapidity is one of the surprising phenomena observed experimentally in heavy-ion collisions from a low center of mass energy of $\sqrt{s}$ =2.5 GeV up to a ultra-relativistic energy of $\sqrt{s}$ =5 TeV. Three approaches have been advanced to describe the cluster formation: coalescence at kinetic freeze-out, cluster formation during the entire heavy-ion collision by potential interaction between nucleons and deuteron production by hadronic reactions. We identify experimental observables, which can discriminate these production mechanisms for deuterons.Comment: typos correcte

FRIGA, A New Approach To Identify Isotopes and Hypernuclei In N-Body Transport Models

We present a new algorithm to identify fragments in computer simulations of relativistic heavy ion collisions. It is based on the simulated annealing technique and can be applied to n-body transport models like the Quantum Molecular Dynamics. This new approach is able to predict isotope yields as well as hyper-nucleus production. In order to illustrate its predicting power, we confront this new method to experimental data, and show the sensitivity on the parameters which govern the cluster formation

Influence of the in-medium pion dispersion relation in heavy ion collisions

We investigate the influence of medium corrections to the pion dispersion relation on the pion dynamics in intermediate energy heavy ion collisions. To do so a pion potential is extracted from the in-medium dispersion relation and used in QMD calculations and thus we take care of both, real and imaginary part of the pion optical potential. The potentials are determined from different sources, i.e. from the $\Delta$--hole model and from phenomenological approaches. Depending on the strength of the potential a reduction of the anti-correlation of pion and nucleon flow in non-central collisions is observed as well as an enhancement of the high energetic yield in transverse pion spectra. A comparison to experiments, in particular to $p_t$-spectra for the reaction Ca+Ca at 1 GeV/nucleon and the pion in-plane flow in Ne+Pb collisions at 800 MeV/nucleon, generally favours a weak potential.Comment: 25 pages, using REVTeX, 6 postscript figures; replaced by published versio

Microcanonical Treatment of Hadronizing the Quark-Gluon Plasma

We recently introduced a completely new way to study ultrarelativistic nuclear scattering by providing a link between the string model approach and a statistical description. A key issue is the microcanonical treatment of hadronizing individual quark matter droplets. In this paper we describe in detail the hadronization of these droplets according to n-body phase space, by using methods of statistical physics, i.e. constructing Markov chains of hadron configurations.Comment: Complete paper enclosed as postscript file (uuencoded