[1] Goethe Univ Frankfurt, Inst Theoret Phys, D-60325 Frankfurt, Germany
[2] Univ Erlangen Nurnberg, Inst Theoret Phys 2, D-91058 Erlangen, Germany
[3] Gesell Schwerionenforsch mbH, D-64291 Darmstadt, Germany
[4] Oak Ridge Natl Lab, Joint Inst Heavy Ion Res, Oak Ridge, TN 37831 USA