UrQMD-2.3 - Changes and Comparisons
  The new version of the Ultra-relativistic Quantum Molecular Dynamics model (UrQMD-2.3) is presented. The Ultra-relativistic Quantum Molecular Dynamics model (UrQMD) is a microscopic many body approach to pp, pA and AA interactions at relativistic energies. The major updates and changes are explained and a comparison to the previous version (UrQMD-1.3p1) in the context of the available data is performed. The plots and numerical data tables for hadron (i.e. $\pi$, K, p, $\bar{p}$, $\Lambda$, $\bar{\Lambda}$, $\Xi$, $\bar{\Xi}$, $\Omega$, $\bar{\Omega}$) multiplicities, and mean transverse mass momenta, $<m_T > -m_0$ excitation functions, transverse mass spectra and rapidity distributions in pp and central Au+Au/Pb+Pb reactions from $E_{\rm lab}=2A $GeV to $\sqrt{s}_{\rm NN}=200$ GeV are provided in this paper. The source code of UrQMD-2.3 is available at http://www.th.physik.uni-frankfurt.de/~urqmd 
Hannah Petersen, Marcus Bleicher, Steffen A. Bass and Horst St\"ocker