Marcus Bleicher

Microscopic models for ultrarelativistic heavy ion collisions

In this paper, the concepts of microscopic transport theory are introduced and the features and shortcomings of the most commonly used ansatzes are discussed. In particular, the Ultrarelativistic Quantum Molecular Dynamics (UrQMD) transport model is described in great detail. Based on the same principles as QMD and RQMD, it incorporates a vastly extended collision term with full baryon-antibaryon symmetry, 55 baryon and 32 meson species. Isospin is explicitly treated for all hadrons. The range of applicability stretches from

Relativistic hadron-hadron collisions in the ultra-relativistic quantum molecular dynamics model

E_{lab} 200

Event-by-event simulation of the three-dimensional hydrodynamic evolution from flux tube initial conditions in ultrarelativistic heavy ion collisions

GeV/nucleon, allowing for a consistent calculation of excitation functions from the intermediate energy domain up to ultrarelativistic energies. The main physics topics under discussion are stopping, particle production and collective flow.

Strangeness dynamics and transverse pressure in relativistic nucleus-nucleus collisions

Hadron-hadron (h-h) collisions at high energies are investigated in the ultra-relativistic quantum molecular dynamics (UrQMD) approach. This microscopic transport model describes the phenomenology of hadronic interactions at low and intermediate energies ( 5 GeV, the excitation of colour strings and their subsequent fragmentation into hadrons dominates the multiple production of particles in the UrQMD model. The model shows a fair overall agreement with a large body of experimental h-h data over a wide range of h-h centre-of-mass energies. Hadronic reaction data with higher precision would be useful to support the use of the UrQMD model for relativistic heavy-ion collisions.

Collective Flow Signals the Quark-Gluon Plasma

We present a sophisticated treatment of the hydrodynamic evolution of ultrarelativistic heavy ion collisions, based on the following features: initial conditions obtained from a flux tube approach, compatible with the string model and the color glass condensate picture; an event-by-event procedure, taking into the account the highly irregular space structure of single events, being experimentally visible via so-called ridge structures in two-particle correlations; the use of an efficient code for solving the hydrodynamic equations in 3 + 1 dimensions, including the conservation of baryon number, strangeness, and electric charge; the employment of a realistic equation of state, compatible with lattice gauge results; the use of a complete hadron resonance table, making our calculations compatible with the results from statistical models; and a hadronic cascade procedure after hadronization from the thermal matter at an early time.

Black hole remnants at the LHC

We investigate hadron production as well as transverse hadron spectra from proton-proton, proton-nucleus and nucleus-nucleus collisions from 2

Evidence for Flow from Hydrodynamic Simulations of

A\cdot

p

GeV to 21.3

-Pb Collisions at 5.02 TeV from

A\cdot

\nu_2

TeV within two independent transport approaches (HSD and UrQMD) that are based on quark, diquark, string and hadronic degrees of freedom. The comparison to experimental data on transverse mass spectra from