[1] IST NAZL FIS NUCL, I-80125 NAPLES, ITALY
[2] UNIV BARI, DIPARTIMENTO FIS, I-70126 BARI, ITALY
[3] IST NAZL FIS NUCL, I-70126 BARI, ITALY
[4] UNIV BOLOGNA, DIPARTIMENTO FIS, I-40126 BOLOGNA, ITALY
[5] IST NAZL FIS NUCL, I-40126 BOLOGNA, ITALY
[6] BOSTON UNIV, DEPT PHYS, BOSTON, MA 02215 USA
[7] CALTECH, PASADENA, CA 91125 USA
[8] DREXEL UNIV, DEPT PHYS, PHILADELPHIA, PA 19104 USA
[9] IST NAZL FIS NUCL, LAB NAZL FRASCATI, I-00044 FRASCATI, ITALY
[10] IST NAZL FIS NUCL, LAB NAZL GRAN SASSO, I-67010 ASSERGI LAQUILA, ITALY
[11] INDIANA UNIV, DEPT PHYS, BLOOMINGTON, IN 47405 USA
[12] INDIANA UNIV, DEPT ASTRON, BLOOMINGTON, IN 47405 USA
[13] UNIV AQUILA, DIPARTIMENTO FIS, I-67100 LAQUILA, ITALY
[14] IST NAZL FIS NUCL, I-67100 LAQUILA, ITALY
[15] UNIV LECCE, DIPARTIMENTO FIS, I-73100 LECCE, ITALY
[16] IST NAZL FIS NUCL, I-73100 LECCE, ITALY
[17] UNIV MICHIGAN, DEPT PHYS, ANN ARBOR, MI 48109 USA
[18] IST NAZL FIS NUCL, I-56010 PISA, ITALY
[19] UNIV PISA, DIPARTIMENTO FIS, I-56010 PISA, ITALY
[20] UNIV ROMA LA SAPIENZA, DIPARTIMENTO FIS, I-00185 ROME, ITALY
[21] IST NAZL FIS NUCL, I-00185 ROME, ITALY
[22] TEXAS A&M UNIV, DEPT PHYS, COLLEGE STN, TX 77843 USA
[23] UNIV TURIN, DIPARTIMENTO FIS SPERIMENTALE, I-10125 TURIN, ITALY
[24] IST NAZL FIS NUCL, I-10125 TURIN, ITALY