Observation of the suppression of the flux of cosmic rays above 4 x 10 (19) eV.
Phys Rev Lett 101:6 (2008) 061101
Authors:
J Abraham, P Abreu, M Aglietta, C Aguirre, D Allard, I Allekotte, J Allen, P Allison, J Alvarez-Muñiz, M Ambrosio, L Anchordoqui, S Andringa, A Anzalone, C Aramo, S Argirò, K Arisaka, E Armengaud, F Arneodo, F Arqueros, T Asch, H Asorey, P Assis, BS Atulugama, J Aublin, M Ave, G Avila, T Bäcker, D Badagnani, AF Barbosa, D Barnhill, SLC Barroso, B Baughman, P Bauleo, JJ Beatty, T Beau, BR Becker, KH Becker, JA Bellido, S Benzvi, C Berat, T Bergmann, P Bernardini, X Bertou, PL Biermann, P Billoir, O Blanch-Bigas, F Blanco, P Blasi, C Bleve, H Blümer, M Bohácová, C Bonifazi, R Bonino, J Brack, P Brogueira, WC Brown, P Buchholz, A Bueno, RE Burton, NG Busca, KS Caballero-Mora, B Cai, DV Camin, L Caramete, R Caruso, W Carvalho, A Castellina, O Catalano, G Cataldi, L Cazon, R Cester, J Chauvin, A Chiavassa, JA Chinellato, A Chou, J Chudoba, J Chye, PDJ Clark, RW Clay, E Colombo, R Conceição, B Connolly, F Contreras, J Coppens, A Cordier, U Cotti, S Coutu, CE Covault, A Creusot, A Criss, J Cronin, A Curutiu, S Dagoret-Campagne, K Daumiller, BR Dawson, RM de Almeida, C De Donato, SJ de Jong, G De La Vega, WJM de Mello Junior, JRT de Mello Neto, I De Mitri, V de Souza, L Del Peral, O Deligny, A Della Selva, C Delle Fratte, H Dembinski, C Di Giulio, JC Diaz, PN Diep, C Dobrigkeit, JC D'Olivo, PN Dong, D Dornic, A Dorofeev, JC Dos Anjos, MT Dova, D D'Urso, I Dutan, MA Duvernois, R Engel, L Epele, M Erdmann, CO Escobar, A Etchegoyen, P Facal San Luis, H Falcke, G Farrar, AC Fauth, N Fazzini, F Ferrer, A Ferrero, B Fick, A Filevich, A Filipcic, I Fleck, CE Fracchiolla, W Fulgione, B García, D García Gámez, D Garcia-Pinto, X Garrido, H Geenen, G Gelmini, H Gemmeke, PL Ghia, M Giller, H Glass, MS Gold, G Golup, F Gomez Albarracin, M Gómez Berisso, P Gonçalves, M Gonçalves do Amaral, D Gonzalez, JG Gonzalez, M González, D Góra, A Gorgi, P Gouffon, V Grassi, AF Grillo, C Grunfeld, Y Guardincerri, F Guarino, GP Guedes, J Gutiérrez, JD Hague, V Halenka, JC Hamilton, P Hansen, D Harari, S Harmsma, JL Harton, A Haungs, T Hauschildt, MD Healy, T Hebbeker, G Hebrero, D Heck, C Hojvat, VC Holmes, P Homola, JR Hörandel, A Horneffer, M Hrabovský, T Huege, M Hussain, M Iarlori, A Insolia, F Ionita, A Italiano, M Kaducak, KH Kampert, T Karova, P Kasper, B Kégl, B Keilhauer, E Kemp, RM Kieckhafer, HO Klages, M Kleifges, J Kleinfeller, R Knapik, J Knapp, D-H Koang, A Krieger, O Krömer, D Kuempel, N Kunka, A Kusenko, G La Rosa, C Lachaud, BL Lago, D Lebrun, P Lebrun, J Lee, MA Leigui de Oliveira, A Letessier-Selvon, M Leuthold, I Lhenry-Yvon, R López, A Lopez Agüera, J Lozano Bahilo, A Lucero, R Luna García, MC Maccarone, C Macolino, S Maldera, G Mancarella, ME Manceñido, D Mandat, P Mantsch, AG Mariazzi, IC Maris, HR Marquez Falcon, D Martello, J Martínez, O Martínez Bravo, HJ Mathes, J Matthews, JAJ Matthews, G Matthiae, D Maurizio, PO Mazur, T McCauley, M McEwen, RR McNeil, MC Medina, G Medina-Tanco, D Melo, E Menichetti, A Menschikov, C Meurer, R Meyhandan, MI Micheletti, G Miele, W Miller, S Mollerach, M Monasor, D Monnier Ragaigne, F Montanet, B Morales, C Morello, JC Moreno, C Morris, M Mostafá, MA Muller, R Mussa, G Navarra, JL Navarro, S Navas, P Necesal, L Nellen, C Newman-Holmes, D Newton, PT Nhung, N Nierstenhoefer, D Nitz, D Nosek, L Nozka, J Oehlschläger, T Ohnuki, A Olinto, VM Olmos-Gilbaja, M Ortiz, F Ortolani, S Ostapchenko, L Otero, N Pacheco, D Pakk Selmi-Dei, M Palatka, J Pallotta, G Parente, E Parizot, S Parlati, S Pastor, M Patel, T Paul, V Pavlidou, K Payet, M Pech, J Pekala, R Pelayo, IM Pepe, L Perrone, R Pesce, S Petrera, P Petrinca, Y Petrov, A Pichel, R Piegaia, T Pierog, M Pimenta, T Pinto, V Pirronello, O Pisanti, M Platino, J Pochon, P Privitera, M Prouza, EJ Quel, J Rautenberg, A Redondo, S Reucroft, B Revenu, FAS Rezende, J Ridky, S Riggi, M Risse, C Rivière, V Rizi, M Roberts, C Robledo, G Rodriguez, J Rodriguez Martino, J Rodriguez Rojo, I Rodriguez-Cabo, MD Rodríguez-Frías, G Ros, J Rosado, M Roth, B Rouillé-d'Orfeuil, E Roulet, AC Rovero, F Salamida, H Salazar, G Salina, F Sánchez, M Santander, CE Santo, EM Santos, F Sarazin, S Sarkar, R Sato, V Scherini, H Schieler, A Schmidt, F Schmidt, T Schmidt, O Scholten, P Schovánek, F Schroeder, S Schulte, F Schüssler, SJ Sciutto, M Scuderi, A Segreto, D Semikoz, M Settimo, RC Shellard, I Sidelnik, BB Siffert, G Sigl, N Smetniansky De Grande, A Smiałkowski, R Smída, AGK Smith, BE Smith, GR Snow, P Sokolsky, P Sommers, J Sorokin, H Spinka, R Squartini, E Strazzeri, A Stutz, F Suarez, T Suomijärvi, AD Supanitsky, MS Sutherland, J Swain, Z Szadkowski, J Takahashi, A Tamashiro, A Tamburro, T Tarutina, O Taşcău, R Tcaciuc, NT Thao, D Thomas, R Ticona, J Tiffenberg, C Timmermans, W Tkaczyk, CJ Todero Peixoto, B Tomé, A Tonachini, I Torres, P Travnicek, A Tripathi, G Tristram, D Tscherniakhovski, V Tuci, M Tueros, V Tunnicliffe, R Ulrich, M Unger, M Urban, JF Valdés Galicia, I Valiño, L Valore, AM van den Berg, V van Elewyck, RA Vázquez, D Veberic, A Veiga, A Velarde, T Venters, V Verzi, M Videla, L Villaseñor, S Vorobiov, L Voyvodic, H Wahlberg, P Wahrlich, O Wainberg, P Walker, D Warner, AA Watson, S Westerhoff, G Wieczorek, L Wiencke, B Wilczyńska, H Wilczyński, C Wileman, MG Winnick, H Wu, B Wundheiler, T Yamamoto, P Younk, E Zas, D Zavrtanik, M Zavrtanik, I Zaw, A Zepeda, M Ziolkowski, Pierre Auger Collaboration
Abstract:
The energy spectrum of cosmic rays above 2.5 x 10;{18} eV, derived from 20,000 events recorded at the Pierre Auger Observatory, is described. The spectral index gamma of the particle flux, J proportional, variantE;{-gamma}, at energies between 4 x 10;{18} eV and 4 x 10;{19} eV is 2.69+/-0.02(stat)+/-0.06(syst), steepening to 4.2+/-0.4(stat)+/-0.06(syst) at higher energies. The hypothesis of a single power law is rejected with a significance greater than 6 standard deviations. The data are consistent with the prediction by Greisen and by Zatsepin and Kuz'min.
