[1] Univ Bari, Dipartimento Fis, I-70126 Bari, Italy
[2] Ist Nazl Fis Nucl, I-70126 Bari, Italy
[3] Ist Nazl Fis Nucl, Lab Nazl Frascati, I-00044 Frascati, Roma, Italy
[4] Ist Nazl Fis Nucl, I-20133 Milan, Italy
[5] Univ Bologna, Dipartimento Fis, I-40126 Bologna, Italy
[6] Ist Nazl Fis Nucl, I-40126 Bologna, Italy
[7] Univ Lecce, Dipartimento Fis, I-73100 Lecce, Italy
[8] Ist Nazl Fis Nucl, I-73100 Lecce, Italy
[9] Indiana Univ, Dept Phys, Bloomington, IN 47405 USA
[10] Indiana Univ, Dept Astron, Bloomington, IN 47405 USA
[11] Univ Rome Tre, Dipartimento Fis, I-00146 Rome, Italy
[12] Ist Nazl Fis Nucl, Sez Roma Tre, I-00146 Rome, Italy
[13] Univ Aquila, Dipartimento Fis, I-67100 Laquila, Italy
[14] Ist Nazl Fis Nucl, I-67100 Laquila, Italy
[15] CNR, Ist IASF, I-40129 Bologna, Italy
[16] Univ Michigan, Dept Phys, Ann Arbor, MI 48109 USA
[17] Penn State Univ, Dept Phys, University Pk, PA 16802 USA
[18] Univ Mohamed I, Fac Sci, LPTP, Oujda, Morocco
[19] Univ Trieste, I-34100 Trieste, Italy
[20] Ist Nazl Fis Nucl, I-34100 Trieste, Italy
[21] Boston Univ, Dept Phys, Boston, MA 02215 USA
[22] Univ Minnesota, Duluth Phys Dept, Duluth, MN 55812 USA
[23] Univ Rome, Dipartimento Energet, I-00185 Rome, Italy
[24] MIT, Dept Phys, Cambridge, MA 02139 USA
[25] Intervideo Inc, Torrance, CA 90505 USA
[26] Univ Roma La Sapienza, Dipartimento Fis, I-00185 Rome, Italy
[27] Ist Nazl Fis Nucl, I-00185 Rome, Italy
[28] Univ Calabria, Dipartimento Fis, I-87036 Arcavacata Di Rende, Cosenza, Italy
[29] Drexel Univ, Dept Phys, Philadelphia, PA 19104 USA
[30] Macalester Coll, Dept Phys & Astron, St Paul, MN 55105 USA
[31] Univ Turin, Dipartimento Fis Sperimentale, I-10125 Turin, Italy
[32] Ist Nazl Fis Nucl, I-10125 Turin, Italy
[33] Inst Space Sci, Bucharest 76900, Romania
[34] Univ Basilicata, I-85100 Potenza, Italy
[35] Univ Piemonte Orientale, Dipartimento Sci & Tecnol Avanzate, I-15100 Alessandria, Italy
[36] Texas A&M Univ, Dept Phys, College Stn, TX 77843 USA
[37] Resonance Photon, Markham, ON, Canada
[38] Univ Naples, Dipartimento Fis, I-80125 Naples, Italy
[39] Ist Nazl Fis Nucl, I-80125 Naples, Italy
[40] Ist Nazl Fis Nucl, Lab Nazl Gran Sasso, I-67010 Assergi, Aquila, Italy
[41] Univ Pisa, Dipartimento Fis, I-56010 Pisa, Italy
[42] Ist Nazl Fis Nucl, I-56010 Pisa, Italy
[43] CALTECH, Pasadena, CA 91125 USA