1. Institute of Particle and Nuclear Physics, Charles University, V.Holešovičkách 2, CZ-18000 Praha 8, Czech Republic
2. Dipartimento di Scienze Fisiche, Universitá di Napoli “Federico II”, Italy
3. Istituto Nazionale di Fisica Nucleare, Monte S Angelo, Via Cinthia, 1-80126 Napoli, Italy
4. Departament de Física, Universitat de les Illes Balears, E-07122 Palma de Mallorca, Spain
5. Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, 141980 Dubna, Russia