[1] Columbia Univ, Dept Phys, New York, NY USA
[2] INFN, Lab Nazl Gran Sasso, Laquila, Italy
[3] Gran Sasso Sci Inst, Laquila, Italy
[4] Univ Bologna, Dept Phys & Astron, Bologna, Italy
[5] INFN Bologna, Bologna, Italy
[6] Nikhef, Amsterdam, Netherlands
[7] Univ Amsterdam, Amsterdam, Netherlands
[8] Weizmann Inst Sci, Dept Particle Phys & Astrophys, Rehovot, Israel
[9] Univ Calif Los Angeles, Phys & Aston Dept, Los Angeles, CA USA
[10] New York Univ Abu Dhabi, Abu Dhabi, U Arab Emirates
[11] Univ Zurich, Phys Inst, Zurich, Switzerland
[12] Univ Coimbra, Dept Phys, Coimbra, Portugal
[13] Johannes Gutenberg Univ Mainz, Inst Phys & Exzellenzcluster PRISMA, Mainz, Germany
[14] Purdue Univ, Dept Phys & Astron, W Lafayette, IN USA
[15] Rensselaer Polytech Inst, Dept Phys Appl Phys & Astron, Troy, NY USA
[16] Max Planck Inst Kernphys, Heidelberg, Germany
[17] Wilhelms Univ Munster, Inst Kerphys, Munster, Germany
[18] Univ Bern, Albert Einstein Ctr Fundamental Phys, Bern, Switzerland
[19] Univ Nantes, CNRS, In2p3, Ecole Mines Nantes,SUBATECH, Nantes, France
[20] Shanghai Jiao Tong Univ, Dept Phys & Astron, Shanghai, Peoples R China
[21] INFN Torino, Turin, Italy
[22] Osservatorio Astrofis Torino, Turin, Italy
[23] Rice Univ, Dept Phys & Astron, Houston, TX USA
[24] Coimbra Engn Inst, Coimbra, Portugal
[25] Univ Valencia, CSIC, IFIC, Valencia, Spain