[1] Ist Nazl Fis Nucl, Lab Nazl Gran Sasso, I-67010 Assergi, AQ, Italy
[2] Univ Aquila, Dipartimento Sci Fis & Chim, I-67100 Coppito, AQ, Italy
[3] Univ Roma La Sapienza, Dipartimento Fis, I-00185 Rome, Italy
[4] Ist Nazl Fis Nucl, Sez Roma, I-00185 Rome, Italy
[5] DI Mendeleev Univ Chem Technol Russia, Moscow 125047, Russia
[6] Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA
[7] MSP, Inst Nucl Res, UA-3680 Kiev, Ukraine
[8] Univ Genoa, Dipartimento Fis, I-16146 Genoa, Italy
[9] Ist Nazl Fis Nucl, Sez Genova, I-16146 Genoa, Italy
[10] Univ Milano Bicocca, Dipartimento Fis, I-20126 Milan, Italy
[11] Ist Nazl Fis Nucl, Sez Milano Bicocca, I-20126 Milan, Italy