[1] INFN, BOLOGNA, ITALY
[2] INFN, COSENZA, ITALY
[3] INFN, ELOISATRON PROJECT, ERICE, ITALY
[4] UNIV CALABRIA, DEPT PHYS, COSENZA, ITALY
[5] PNPI GATCHINA, ST PETERSBURG, RUSSIA
[6] WORLD LAB, LAUSANNE, SWITZERLAND
[7] CERN, CH-1211 GENEVA 23, SWITZERLAND
[8] UNIV BOLOGNA, DEPT PHYS, I-40126 BOLOGNA, ITALY
[9] UNIV PISA, DEPT PHYS, I-56100 PISA, ITALY