[1] Columbia Univ, Dept Phys, New York, NY 10027 USA
[2] Nikhef, Sci Pk, NL-1098XG Amsterdam, Netherlands
[3] Univ Amsterdam, Sci Pk, NL-1098XG Amsterdam, Netherlands
[4] INFN, Lab Nazl Gran Sasso, I-67100 Laquila, Italy
[5] Gran Sasso Sci Inst, I-67100 Laquila, Italy
[6] Univ Bologna, Dept Phys & Astrophys, I-40126 Bologna, Italy
[7] INFN Bologna, I-40126 Bologna, Italy
[8] Johannes Gutenberg Univ Mainz, Inst Phys & Exzellenzcluster PRISMA, D-55099 Mainz, Germany
[9] Univ Coimbra, Dept Phys, LIBPhys, P-3004516 Coimbra, Portugal
[10] New York Univ Abu Dhabi, Abu Dhabi, U Arab Emirates
[11] Univ Zurich, Phys Inst, CH-8057 Zurich, Switzerland
[12] Stockholm Univ, AlbaNova, Dept Phys, Oskar Klein Ctr, S-10691 Stockholm, Sweden
[13] Rensselaer Polytech Inst, Dept Phys Appl Phys & Astron, Troy, NY 12180 USA
[14] Max Planck Inst Kernphys, D-69117 Heidelberg, Germany
[15] Weizmann Inst Sci, Dept Particle Phys & Astrophys, IL-7610001 Rehovot, Israel
[16] Univ Freiburg, Phys Inst, D-79104 Freiburg, Germany
[17] Purdue Univ, Dept Phys & Astron, W Lafayette, IN 47907 USA
[18] Univ Nantes, CNRS, IN2P3, SUBATECH,IMT Atlantique, F-44307 Nantes, France
[19] Univ Calif San Diego, Dept Phys, San Diego, CA 92093 USA
[20] Westfalische Wilhelms Univ Munster, Inst Kernphys, D-48149 Munster, Germany
[21] INFN Torino, I-10125 Turin, Italy
[22] Osserv Astron Torino, I-10125 Turin, Italy
[23] Univ Chicago, Dept Phys, Chicago, IL 60637 USA
[24] Univ Chicago, Kavli Inst Cosmol Phys, Chicago, IL 60637 USA
[25] Rice Univ, Dept Phys & Astron, Houston, TX 77005 USA
[26] Univ Paris 06, Univ Paris Diderot, CNRS, IN2P3,LPNHE, F-75252 Paris, France
[27] Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA
[28] Univ Bern, Albert Einstein Ctr Fundamental Phys, Bern, Switzerland
[29] Coimbra Engn Inst, Coimbra, Portugal