1. Department of Physics and Joint Institute of Nuclear Astrophysics, University of Notre Dame, Notre Dame, Indiana 46556;
2. Karlsruhe Institute of Technology, Campus North, D-76021 Karlsruhe, Germany;
3. GSI Helmholtzzentrum für Schwerionenforschung GmbH, D-64291 Darmstadt, Germany; Technical University of Darmstadt, D-64289 Darmstadt, Germany; and Frankfurt Institute for Advanced Studies, D-60438 Frankfurt, Germany;