Measurement of the depth of maximum of extensive air showers above 10{18} eV.
Phys Rev Lett 104:9 (2010) 091101
Authors:
J Abraham, P Abreu, M Aglietta, EJ Ahn, D Allard, I Allekotte, J Allen, J Alvarez-Muñiz, M Ambrosio, L Anchordoqui, S Andringa, T Anticić, A Anzalone, C Aramo, E Arganda, K Arisaka, F Arqueros, H Asorey, P Assis, J Aublin, M Ave, G Avila, T Bäcker, D Badagnani, M Balzer, KB Barber, AF Barbosa, SLC Barroso, B Baughman, P Bauleo, JJ Beatty, BR Becker, KH Becker, A Bellétoile, JA Bellido, S Benzvi, C Berat, T Bergmann, X Bertou, PL Biermann, P Billoir, O Blanch-Bigas, F Blanco, M Blanco, C Bleve, H Blümer, M Bohácová, D Boncioli, C Bonifazi, R Bonino, N Borodai, J Brack, P Brogueira, WC Brown, R Bruijn, P Buchholz, A Bueno, RE Burton, NG Busca, KS Caballero-Mora, L Caramete, R Caruso, A Castellina, O Catalano, G Cataldi, L Cazon, R Cester, J Chauvin, A Chiavassa, JA Chinellato, A Chou, J Chudoba, RW Clay, E Colombo, MR Coluccia, R Conceição, F Contreras, H Cook, MJ Cooper, J Coppens, A Cordier, U Cotti, S Coutu, CE Covault, A Creusot, A Criss, J Cronin, A Curutiu, S Dagoret-Campagne, R Dallier, K Daumiller, BR Dawson, RM de Almeida, M De Domenico, C De Donato, SJ de Jong, G De La Vega, WJM de Mello Junior, JRT de Mello Neto, I De Mitri, V de Souza, KD de Vries, G Decerprit, L Del Peral, O Deligny, A Della Selva, C Delle Fratte, H Dembinski, C Di Giulio, JC Diaz, ML Díaz Castro, PN Diep, C Dobrigkeit, JC D'Olivo, PN Dong, A Dorofeev, JC Dos Anjos, MT Dova, D D'Urso, I Dutan, MA Duvernois, J Ebr, R Engel, M Erdmann, CO Escobar, A Etchegoyen, P Facal San Luis, H Falcke, G Farrar, AC Fauth, N Fazzini, A Ferrero, B Fick, A Filevich, A Filipcic, I Fleck, S Fliescher, CE Fracchiolla, ED Fraenkel, U Fröhlich, W Fulgione, RF Gamarra, S Gambetta, B García, D García Gámez, D Garcia-Pinto, X Garrido, G Gelmini, H Gemmeke, PL Ghia, U Giaccari, M Giller, H Glass, LM Goggin, MS Gold, G Golup, F Gomez Albarracin, M Gómez Berisso, P Gonçalves, D Gonzalez, JG Gonzalez, D Góra, A Gorgi, P Gouffon, SR Gozzini, E Grashorn, S Grebe, M Grigat, AF Grillo, Y Guardincerri, F Guarino, GP Guedes, JD Hague, V Halenka, P Hansen, D Harari, S Harmsma, JL Harton, A Haungs, T Hebbeker, D Heck, AE Herve, C Hojvat, VC Holmes, P Homola, JR Hörandel, A Horneffer, M Hrabovský, T Huege, M Hussain, M Iarlori, A Insolia, F Ionita, A Italiano, S Jiraskova, K Kadija, M Kaducak, KH Kampert, T Karova, P Kasper, B Kégl, B Keilhauer, A Keivani, J Kelley, E Kemp, RM Kieckhafer, HO Klages, M Kleifges, J Kleinfeller, R Knapik, J Knapp, D-H Koang, A Krieger, O Krömer, D Kruppke-Hansen, F Kuehn, D Kuempel, K Kulbartz, N Kunka, A Kusenko, G La Rosa, C Lachaud, BL Lago, P Lautridou, MSAB Leão, D Lebrun, P Lebrun, J Lee, MA Leigui de Oliveira, A Lemiere, A Letessier-Selvon, I Lhenry-Yvon, R López, A Lopez Agüera, K Louedec, J Lozano Bahilo, A Lucero, M Ludwig, H Lyberis, MC Maccarone, C Macolino, S Maldera, D Mandat, P Mantsch, AG Mariazzi, V Marin, IC Maris, HR Marquez Falcon, G Marsella, D Martello, O Martínez Bravo, HJ Mathes, J Matthews, JAJ Matthews, G Matthiae, D Maurizio, PO Mazur, M McEwen, G Medina-Tanco, M Melissas, D Melo, E Menichetti, A Menshikov, C Meurer, S Micanović, MI Micheletti, W Miller, L Miramonti, S Mollerach, M Monasor, D Monnier Ragaigne, F Montanet, B Morales, C Morello, E Moreno, JC Moreno, C Morris, M Mostafá, S Mueller, MA Muller, R Mussa, G Navarra, JL Navarro, S Navas, P Necesal, L Nellen, PT Nhung, N Nierstenhoefer, D Nitz, D Nosek, L Nozka, M Nyklicek, J Oehlschläger, A Olinto, P Oliva, VM Olmos-Gilbaja, M Ortiz, N Pacheco, D Pakk Selmi-Dei, M Palatka, J Pallotta, N Palmieri, G Parente, E Parizot, S Parlati, A Parra, J Parrisius, RD Parsons, S Pastor, T Paul, V Pavlidou, K Payet, M Pech, J Pekala, R Pelayo, IM Pepe, L Perrone, R Pesce, E Petermann, S Petrera, P Petrinca, A Petrolini, Y Petrov, J Petrovic, C Pfendner, R Piegaia, T Pierog, M Pimenta, V Pirronello, M Platino, VH Ponce, M Pontz, P Privitera, M Prouza, EJ Quel, J Rautenberg, O Ravel, D Ravignani, A Redondo, B Revenu, FAS Rezende, J Ridky, S Riggi, M Risse, P Ristori, C Rivière, V Rizi, C Robledo, G Rodriguez, J Rodriguez Martino, J Rodriguez Rojo, I Rodriguez-Cabo, MD Rodríguez-Frías, G Ros, J Rosado, T Rossler, M Roth, B Rouillé-d'Orfeuil, E Roulet, AC Rovero, F Salamida, H Salazar, G Salina, F Sánchez, M Santander, CE Santo, E Santos, EM Santos, F Sarazin, S Sarkar, R Sato, N Scharf, V Scherini, H Schieler, P Schiffer, A Schmidt, F Schmidt, T Schmidt, O Scholten, H Schoorlemmer, J Schovancova, P Schovánek, F Schroeder, S Schulte, F Schüssler, D Schuster, SJ Sciutto, M Scuderi, A Segreto, D Semikoz, M Settimo, A Shadkam, RC Shellard, I Sidelnik, BB Siffert, G Sigl, A Smiałkowski, R Smída, GR Snow, P Sommers, J Sorokin, H Spinka, R Squartini, J Stasielak, M Stephan, E Strazzeri, A Stutz, F Suarez, T Suomijärvi, AD Supanitsky, T Susa, MS Sutherland, J Swain, Z Szadkowski, A Tamashiro, A Tamburro, A Tapia, T Tarutina, O Taşcău, R Tcaciuc, D Tcherniakhovski, D Tegolo, NT Thao, D Thomas, J Tiffenberg, C Timmermans, W Tkaczyk, CJ Todero Peixoto, B Tomé, A Tonachini, P Travnicek, DB Tridapalli, G Tristram, E Trovato, M Tueros, R Ulrich, M Unger, M Urban, JF Valdés Galicia, I Valiño, L Valore, AM van den Berg, JR Vázquez, RA Vázquez, D Veberic, T Venters, V Verzi, M Videla, L Villaseñor, S Vorobiov, L Voyvodic, H Wahlberg, P Wahrlich, O Wainberg, D Warner, AA Watson, S Westerhoff, BJ Whelan, G Wieczorek, L Wiencke, B Wilczyńska, H Wilczyński, C Williams, T Winchen, MG Winnick, B Wundheiler, T Yamamoto, P Younk, G Yuan, A Yushkov, E Zas, D Zavrtanik, M Zavrtanik, I Zaw, A Zepeda, M Ziolkowski, Pierre Auger Collaboration
Abstract:
We describe the measurement of the depth of maximum, X{max}, of the longitudinal development of air showers induced by cosmic rays. Almost 4000 events above 10;{18} eV observed by the fluorescence detector of the Pierre Auger Observatory in coincidence with at least one surface detector station are selected for the analysis. The average shower maximum was found to evolve with energy at a rate of (106{-21}{+35}) g/cm{2}/decade below 10{18.24+/-0.05} eV, and (24+/-3) g/cm{2}/decade above this energy. The measured shower-to-shower fluctuations decrease from about 55 to 26 g/cm{2}. The interpretation of these results in terms of the cosmic ray mass composition is briefly discussed.
