1. Dipartimento di Scienze Fisiche, Università di Napoli Federico II, Via Cintia, I-80126, Napoli, Italy
2. Istituto Nazionale di Fisica Nucleare Monte S. Angelo, Via Cintia, I-80126, Napoli, Italy
3. Institute of Particle and Nuclear Physics, Charles University, V.Holešovičkách 2, CZ-18000 Praha 8, Czech Republic
4. Institute for Nuclear Research and Nuclear Energy, 1784 Sofia, Bulgaria
5. BLTP, Joint Institute for Nuclear Research 141980, Dubna, Moscow Region, Russia