[1] Univ Athens, Dept Phys, GR-15771 Athens, Greece
[2] Univ Bern, Inst Phys, CH-3012 Bern, Switzerland
[3] Univ Bern, Inst Theoret Phys, CH-3012 Bern, Switzerland
[4] CERN, European Org Nucl Res, CH-1211 Geneva, Switzerland
[5] Univ Crete, Dept Phys, Iraklion, Greece
[6] Hellen Open Univ, Sch Sci & Technol, Patras, Greece
[7] Univ Kiel, Inst Expt & Appl Phys, D-24098 Kiel, Germany
[8] Lawrence Berkeley Natl Lab, Berkeley, CA USA
[9] NCSR Demokritos, GR-15310 Athens, Greece
[10] NESTOR Inst Deep Sea Res, Pylos, Greece
[11] Russian Acad Sci, Inst Nucl Res, Moscow, Russia