We report a measurement of the energy spectrum of cosmic rays for energies above 2.5 x 10(18) eV based on 215,030 events recorded with zenith angles below 60 degrees. A key feature of the work is that the estimates of the energies are independent of assumptions about the unknown hadronic physics or of the primary mass composition. The measurement is the most precise made hitherto with the accumulated exposure being so large that the measurements of the flux are dominated by systematic uncertainties except at energies above 5 x 10(19) eV. The principal conclusions are(1) The flattening of the spectrum near 5 x 10(18) eV, the so-called "ankle," is confirmed.(2) The steepening of the spectrum at around 5 x 10(19) eV is confirmed.(3) A new feature has been identified in the spectrum: in the region above the ankle the spectral index gamma of the particle flux (proportional to E-gamma) changes from 2.51 +/- 0.03 (stat) +/- 0.05 (syst) to 3.05 +/- 0.05 (stat) +/- 0.10 (syst) before changing sharply to 5.1 +/- 0.3 (stat) +/- 0.1 (syst) above 5 x 10(19) eV.(4) No evidence for any dependence of the spectrum on declination has been found other than a mild excess from the Southern Hemisphere that is consistent with the anisotropy observed above 8 x 10(18) eV. (The Pierre Auger Collaboration)

Measurement of the cosmic-ray energy spectrum above 2.5×1018  eV using the Pierre Auger Observatory / A. Aab, P. Abreu, M. Aglietta, J. . Albury, I. Allekotte, A. Almela, J. Alvarez Castillo, J. Alvarez-Muñiz, R. Alves Batista, G. . Anastasi, L. Anchordoqui, B. Andrada, S. Andringa, C. Aramo, P. . Araújo Ferreira, H. Asorey, P. Assis, G. Avila, A. . Badescu, A. Bakalova, A. Balaceanu, F. Barbato, R. . Barreira Luz, K. . Becker, J. . Bellido, C. Berat, M. . Bertaina, X. Bertou, P. . Biermann, T. Bister, J. Biteau, A. Blanco, J. Blazek, C. Bleve, M. Boháčová, D. Boncioli, C. Bonifazi, L. Bonneau Arbeletche, N. Borodai, A. . Botti, J. Brack, T. Bretz, F. . Briechle, P. Buchholz, A. Bueno, S. Buitink, M. Buscemi, K. . Caballero-Mora, L. Caccianiga, L. Calcagni, A. Cancio, F. Canfora, I. Caracas, J. . Carceller, R. Caruso, A. Castellina, F. Catalani, G. Cataldi, L. Cazon, M. Cerda, J. . Chinellato, K. Choi, J. Chudoba, L. Chytka, R. . Clay, A. . Cobos Cerutti, R. Colalillo, A. Coleman, M. . Coluccia, R. Conceição, A. Condorelli, G. Consolati, F. Contreras, F. Convenga, C. . Covault, S. Dasso, K. Daumiller, B. . Dawson, J. . Day, R. . de Almeida, J. de Jesús, S. . de Jong, G. De Mauro, J. . . de Mello Neto, I. De Mitri, J. de Oliveira, D. de Oliveira Franco, V. de Souza, E. De Vito, J. Debatin, M. del Río, O. Deligny, H. Dembinski, N. Dhital, C. Di Giulio, A. Di Matteo, M. . Díaz Castro, C. Dobrigkeit, J. . D’Olivo, Q. Dorosti, R. . dos Anjos, M. . Dova, J. Ebr, R. Engel, I. Epicoco, M. Erdmann, C. . Escobar, A. Etchegoyen, H. Falcke, J. Farmer, G. Farrar, A. . Fauth, N. Fazzini, F. Feldbusch, F. Fenu, B. Fick, J. . Figueira, A. Filipčič, T. Fodran, M. . Freire, T. Fujii, A. Fuster, C. Galea, C. Galelli, B. García, A. . Garcia Vegas, H. Gemmeke, F. Gesualdi, A. Gherghel-Lascu, P. . Ghia, U. Giaccari, M. Giammarchi, M. Giller, J. Glombitza, F. Gobbi, F. Gollan, G. Golup, M. Gómez Berisso, P. . Gómez Vitale, J. . Gongora, N. González, I. Goos, D. Góra, A. Gorgi, M. Gottowik, T. . Grubb, F. Guarino, G. . Guedes, E. Guido, S. Hahn, R. Halliday, M. . Hampel, P. Hansen, D. Harari, V. . Harvey, A. Haungs, T. Hebbeker, D. Heck, G. . Hill, C. Hojvat, J. . Hörandel, P. Horvath, M. Hrabovský, T. Huege, J. Hulsman, A. Insolia, P. . Isar, J. . Johnsen, J. Jurysek, A. Kääpä, K. . Kampert, B. Keilhauer, J. Kemp, H. . Klages, M. Kleifges, J. Kleinfeller, M. Köpke, G. Kukec Mezek, B. . Lago, D. Lahurd, R. . Lang, M. . Leigui de Oliveira, V. Lenok, A. Letessier-Selvon, I. Lhenry-Yvon, D. Lo Presti, L. Lopes, R. López, R. Lorek, Q. Luce, A. Lucero, A. Machado Payeras, M. Malacari, G. Mancarella, D. Mandat, B. . Manning, J. Manshanden, P. Mantsch, S. Marafico, A. . Mariazzi, I. . Mariş, G. Marsella, D. Martello, H. Martinez, O. Martínez Bravo, M. Mastrodicasa, H. . Mathes, J. Matthews, G. Matthiae, E. Mayotte, P. . Mazur, G. Medina-Tanco, D. Melo, A. Menshikov, K.-. Merenda, S. Michal, M. . Micheletti, L. Miramonti, D. Mockler, S. Mollerach, F. Montanet, C. Morello, M. Mostafá, A. . Müller, M. . Muller, K. Mulrey, R. Mussa, M. Muzio, W. . Namasaka, L. Nellen, P. . Nguyen, M. Niculescu-Oglinzanu, M. Niechciol, D. Nitz, D. Nosek, V. Novotny, L. Nožka, A. Nucita, L. . Núñez, M. Palatka, J. Pallotta, M. . Panetta, P. Papenbreer, G. Parente, A. Parra, M. Pech, F. Pedreira, J. Pȩkala, R. Pelayo, J. Peña-Rodriguez, J. Perez Armand, M. Perlin, L. Perrone, C. Peters, S. Petrera, T. Pierog, M. Pimenta, V. Pirronello, M. Platino, B. Pont, M. Pothast, P. Privitera, M. Prouza, A. Puyleart, S. Querchfeld, J. Rautenberg, D. Ravignani, M. Reininghaus, J. Ridky, F. Riehn, M. Risse, P. Ristori, V. Rizi, W. Rodrigues de Carvalho, G. Rodriguez Fernandez, J. Rodriguez Rojo, M. . Roncoroni, M. Roth, E. Roulet, A. . Rovero, P. Ruehl, S. . Saffi, A. Saftoiu, F. Salamida, H. Salazar, G. Salina, J. . Sanabria Gomez, F. Sánchez, E. . Santos, E. Santos, F. Sarazin, R. Sarmento, C. Sarmiento-Cano, R. Sato, P. Savina, C. Schäfer, V. Scherini, H. Schieler, M. Schimassek, M. Schimp, F. Schlüter, D. Schmidt, O. Scholten, P. Schovánek, F. . Schröder, S. Schröder, A. Schulz, S. . Sciutto, M. Scornavacche, R. . Shellard, G. Sigl, G. Silli, O. Sima, R. Šmída, P. Sommers, J. . Soriano, J. Souchard, R. Squartini, M. Stadelmaier, D. Stanca, S. Stanič, J. Stasielak, P. Stassi, A. Streich, M. Suárez-Durán, T. Sudholz, T. Suomijärvi, A. . Supanitsky, J. Šupík, Z. Szadkowski, A. Taboada, A. Tapia, C. Timmermans, O. Tkachenko, P. Tobiska, C. . Todero Peixoto, B. Tomé, G. Torralba Elipe, A. Travaini, P. Travnicek, C. Trimarelli, M. Trini, M. Tueros, R. Ulrich, M. Unger, M. Urban, L. Vaclavek, M. Vacula, J. . Valdés Galicia, I. Valiño, L. Valore, A. van Vliet, E. Varela, B. Vargas Cárdenas, A. Vásquez-Ramírez, D. Veberič, C. Ventura, I. . Vergara Quispe, V. Verzi, J. Vicha, L. Villaseñor, J. Vink, S. Vorobiov, H. Wahlberg, A. . Watson, M. Weber, A. Weindl, L. Wiencke, H. Wilczyński, T. Winchen, M. Wirtz, D. Wittkowski, B. Wundheiler, A. Yushkov, O. Zapparrata, E. Zas, D. Zavrtanik, M. Zavrtanik, L. Zehrer, A. Zepeda, M. Ziolkowski, F. Zuccarello, N. Null. - In: PHYSICAL REVIEW D. - ISSN 2470-0010. - 102:6(2020 Sep 16), pp. 062005.1-062005.27. [10.1103/physrevd.102.062005]

Measurement of the cosmic-ray energy spectrum above 2.5×1018  eV using the Pierre Auger Observatory

L. Caccianiga;C. Galelli;L. Miramonti;V. Scherini;
2020

Abstract

We report a measurement of the energy spectrum of cosmic rays for energies above 2.5 x 10(18) eV based on 215,030 events recorded with zenith angles below 60 degrees. A key feature of the work is that the estimates of the energies are independent of assumptions about the unknown hadronic physics or of the primary mass composition. The measurement is the most precise made hitherto with the accumulated exposure being so large that the measurements of the flux are dominated by systematic uncertainties except at energies above 5 x 10(19) eV. The principal conclusions are(1) The flattening of the spectrum near 5 x 10(18) eV, the so-called "ankle," is confirmed.(2) The steepening of the spectrum at around 5 x 10(19) eV is confirmed.(3) A new feature has been identified in the spectrum: in the region above the ankle the spectral index gamma of the particle flux (proportional to E-gamma) changes from 2.51 +/- 0.03 (stat) +/- 0.05 (syst) to 3.05 +/- 0.05 (stat) +/- 0.10 (syst) before changing sharply to 5.1 +/- 0.3 (stat) +/- 0.1 (syst) above 5 x 10(19) eV.(4) No evidence for any dependence of the spectrum on declination has been found other than a mild excess from the Southern Hemisphere that is consistent with the anisotropy observed above 8 x 10(18) eV. (The Pierre Auger Collaboration)
Settore FIS/01 - Fisica Sperimentale
Settore FIS/04 - Fisica Nucleare e Subnucleare
Settore FIS/05 - Astronomia e Astrofisica
16-set-2020
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/1033208
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