[1] McGill Univ, Dept Phys, Montreal, PQ H3A 2T8, Canada
[2] Stockholm Univ, Oskar Klein Ctr Cosmoparticle Phys, SE-10691 Stockholm, Sweden
[3] Stockholm Univ, Dept Phys, SE-10691 Stockholm, Sweden
[4] Univ Wisconsin, Dept Phys, Madison, WI 53706 USA
[5] Univ Wisconsin, Wisconsin IceCube Particle Astrophys Ctr, Madison, WI 53706 USA
[6] Univ Ghent, Dept Phys & Astron, B-9000 Ghent, Belgium
[7] DESY, D-15735 Zeuthen, Germany
[8] Univ Canterbury, Dept Phys & Astron, Christchurch 1, New Zealand
[9] Univ Geneva, Dept Phys Nucl & Corpusculaire, CH-1211 Geneva, Switzerland
[10] Humboldt Univ, Inst Phys, D-12489 Berlin, Germany
[11] Univ Delaware, Bartol Res Inst, Newark, DE 19716 USA
[12] Univ Delaware, Dept Phys & Astron, Newark, DE 19716 USA
[13] S Dakota Sch Mines & Technol, Dept Phys, Rapid City, SD 57701 USA
[14] Univ Calif Irvine, Dept Phys & Astron, Irvine, CA 92697 USA
[15] Johannes Gutenberg Univ Mainz, Inst Phys, D-55099 Mainz, Germany
[16] Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA
[17] Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA
[18] Ohio State Univ, Dept Phys, Columbus, OH 43210 USA
[19] Ohio State Univ, Ctr Cosmol & Astroparticle Phys, Columbus, OH 43210 USA
[20] Ohio State Univ, Dept Astron, Columbus, OH 43210 USA
[21] Univ Libre Bruxelles, Fac Sci, B-1050 Brussels, Belgium
[22] Ruhr Univ Bochum, Fak Phys & Astron, D-44780 Bochum, Germany
[23] Univ Wuppertal, Dept Phys, D-42119 Wuppertal, Germany
[24] Penn State Univ, Dept Phys, University Pk, PA 16802 USA
[25] Univ Maryland, Dept Phys, College Pk, MD 20742 USA
[26] Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA
[27] Rhein Westfal TH Aachen, Inst Phys 3, D-52056 Aachen, Germany
[28] Vrije Univ Brussel, Dienst ELEM, B-1050 Brussels, Belgium
[29] Univ Bonn, Inst Phys, D-53115 Bonn, Germany
[30] Uppsala Univ, Dept Phys & Astron, S-75120 Uppsala, Sweden
[31] Ecole Polytech Fed Lausanne, High Energy Phys Lab, CH-1015 Lausanne, Switzerland
[32] Georgia Inst Technol, Sch Phys, Atlanta, GA 30332 USA
[33] Georgia Inst Technol, Ctr Relativist Astrophys, Atlanta, GA 30332 USA
[34] TU Dortmund Univ, Dept Phys, D-44221 Dortmund, Germany
[35] Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA
[36] Southern Univ, Dept Phys, Baton Rouge, LA 70813 USA
[37] Univ Wisconsin, Dept Astron, Madison, WI 53706 USA
[38] Univ Alberta, Dept Phys, Edmonton, AB T6G 2G7, Canada
[39] Tech Univ Munich, D-85748 Garching, Germany
[40] Univ Adelaide, Sch Chem & Phys, Adelaide, SA 5005, Australia
[41] Los Alamos Natl Lab, Los Alamos, NM 87545 USA
[42] Chiba Univ, Dept Phys, Chiba 2638522, Japan
[43] Clark Atlanta Univ, CTSPS, Atlanta, GA 30314 USA
[44] SUNY Stony Brook, Dept Phys & Astron, Stony Brook, NY 11794 USA
[45] Univ Mons, B-7000 Mons, Belgium
[46] Univ Alabama, Dept Phys & Astron, Tuscaloosa, AL 35487 USA
[47] Univ Wisconsin, Dept Phys, River Falls, WI 54022 USA
[48] Univ Bari, Dipartmento Fis, Sez INFN, I-70126 Bari, Italy
[49] Univ Alaska Anchorage, Dept Phys & Astron, Anchorage, AK 99508 USA
[50] Univ Oxford, Dept Phys, Oxford OX1 3NP, England