1. SUPA, School of Physics and Astronomy, University of Edinburgh, Edinburgh, United Kingdom;
2. Department of Physics, Università degli Studi di Napoli Federico II, Napoli, Italy
3. Institute of Nuclear Physics, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
4. Department of Physics, Università degli Studi di Milano, Milano, Italy
5. Istituto Nazionale di Fisica Nucleare Milano, Milano, Italy
6. Institute for Nuclear Research, Hungarian Academy of Sciences, Debrecen, Hungary