Multi-year search for dark matter annihilations in the Sun with the AMANDA-II and IceCube detectors

ArXiv 1112.184 (2011)

Authors:

IceCube Collaboration, R Abbasi, Y Abdou, T Abu-Zayyad, M Ackermann, J Adams, JA Aguilar, M Ahlers, D Altmann, K Andeen, J Auffenberg, X Bai, M Baker, SW Barwick, R Bay, JL Bazo Alba, K Beattie, JJ Beatty, S Bechet, JK Becker, K-H Becker, M Bell, ML Benabderrahmane, S BenZvi, J Berdermann, P Berghaus, D Berley, E Bernardini, D Bertrand, DZ Besson, D Bindig, M Bissok, E Blaufuss, J Blumenthal, DJ Boersma, C Bohm, D Bose, S Böser, O Botner, L Brayeur, AM Brown, S Buitink, KS Caballero-Mora, M Carson, M Casier, D Chirkin, B Christy, F Clevermann, S Cohen, C Colnard, DF Cowen, AH Cruz Silva, MV D'Agostino, M Danninger, J Daughhetee, JC Davis, C De Clercq, T Degner, F Descamps, P Desiati, G de Vries-Uiterweerd, T DeYoung, JC Díaz-Vélez, M Dierckxsens, J Dreyer, JP Dumm, M Dunkman, J Eisch, RW Ellsworth, O Engdegård, S Euler, PA Evenson, O Fadiran, AR Fazely, A Fedynitch, J Feintzeig, T Feusels, K Filimonov, C Finley, T Fischer-Wasels, S Flis, A Franckowiak, R Franke, TK Gaisser, J Gallagher, L Gerhardt, L Gladstone, T Glüsenkamp, A Goldschmidt, JA Goodman, D Góra, D Grant, T Griesel, A Groß, S Grullon, M Gurtner, C Ha, A Haj Ismail, A Hallgren, F Halzen, K Han, K Hanson, D Heereman, D Heinen, K Helbing, R Hellauer, S Hickford, GC Hill, KD Hoffman, B Hoffmann, A Homeier, K Hoshina, W Huelsnitz, J-P Hülß, PO Hulth, K Hultqvist, S Hussain, A Ishihara, E Jacobi, J Jacobsen, GS Japaridze, H Johansson, A Kappes, T Karg, A Karle, J Kiryluk, F Kislat, SR Klein, J-H Köhne, G Kohnen, H Kolanoski, L Köpke, S Kopper, DJ Koskinen, M Kowalski, T Kowarik, M Krasberg, G Kroll, J Kunnen, N Kurahashi, T Kuwabara, M Labare, K Laihem, H Landsman, MJ Larson, R Lauer, J Lünemann, J Madsen, A Marotta, R Maruyama, K Mase, HS Matis, K Meagher, M Merck, P Mészáros, T Meures, S Miarecki, E Middell, N Milke, J Miller, T Montaruli, R Morse, SM Movit, R Nahnhauer, JW Nam, U Naumann, SC Nowicki, DR Nygren, S Odrowski, A Olivas, M Olivo, A O'Murchadha, S Panknin, L Paul, C Pérez de los Heros, A Piegsa, D Pieloth, J Posselt, PB Price, GT Przybylski, K Rawlins, P Redl, E Resconi, W Rhode, M Ribordy, M Richman, A Rizzo, JP Rodrigues, F Rothmaier, C Rott, T Ruhe, D Rutledge, B Ruzybayev, D Ryckbosch, H-G Sander, M Santander, S Sarkar, K Schatto, T Schmidt, S Schöneberg, A Schönwald, A Schukraft, L Schulte, A Schultes, O Schulz, M Schunck, D Seckel, B Semburg, SH Seo, Y Sestayo, S Seunarine, A Silvestri, GM Spiczak, C Spiering, M Stamatikos, T Stanev, T Stezelberger, RG Stokstad, A Stößl, EA Strahler, R Ström, M Stüer, GW Sullivan, H Taavola, I Taboada, A Tamburro, S Ter-Antonyan, S Tilav, PA Toale, S Toscano, D Tosi, N van Eijndhoven, A Van Overloop, J van Santen, M Vehring1, M Voge, C Walck, T Waldenmaier, M Wallraff, M Walter, R Wasserman, Ch Weaver, C Wendt, S Westerhoff, N Whitehorn, K Wiebe, CH Wiebusch, DR Williams, R Wischnewski, H Wissing, M Wolf, TR Wood, K Woschnagg, C Xu, DL Xu, XW Xu, JP Yanez, G Yodh, S Yoshida, P Zarzhitsky, M Zoll

Abstract:

A search for an excess of muon-neutrinos from dark matter annihilations in the Sun has been performed with the AMANDA-II neutrino telescope using data collected in 812 days of livetime between 2001 and 2006 and 149 days of livetime collected with the AMANDA-II and the 40-string configuration of IceCube during 2008 and early 2009. No excess over the expected atmospheric neutrino background has been observed. We combine these results with the previously published IceCube limits obtained with data taken during 2007 to obtain a total livetime of 1065 days. We provide an upper limit at 90% confidence level on the annihilation rate of captured neutralinos in the Sun, as well as the corresponding muon flux limit at the Earth, both as functions of the neutralino mass in the range 50 GeV-5000 GeV. We also derive a limit on the neutralino-proton spin-dependent and spin-independent cross section. The limits presented here improve the previous results obtained by the collaboration between a factor of two and five, as well as extending the neutralino masses probed down to 50 GeV. The spin-dependent cross section limits are the most stringent so far for neutralino masses above 200 GeV, and well below direct search results in the mass range from 50 GeV to 5 TeV.

Heterotic standard models from smooth calabi-Yau three-folds

Proceedings of Science (2011)

Authors:

LB Anderson, J Gray, A Lukas, E Palti

Abstract:

We describe a new approach to heterotic Calabi-Yau model building, based on the systematic construction of vector bundles with Abelian structure groups. Starting with a relatively small number of Calabi-Yau manifolds, about 400 models with the exact matter spectrum of the supersymmet-ric standard model are found in this way. The additional, normally anomalous U(1) symmetries which arise in these models place strong constraints on the allowed four-dimensional operators and can lead to interesting phenomenological consequences, some of which we discuss.

Searching for soft relativistic jets in Core-collapse Supernovae with the IceCube Optical Follow-up Program

ArXiv 1111.703 (2011)

Authors:

The IceCube Collaboration, R Abbasi, Y Abdou, T Abu-Zayyad, M Ackermann, J Adams, JA Aguilar, M Ahlers, MM Allen, D Altmann, K Andeen, J Auffenberg, X Bai, M Baker, SW Barwick, R Bay, JL Bazo Alba, K Beattie, JJ Beatty, S Bechet, JK Becker, K-H Becker, ML Benabderrahmane, S BenZvi, J Berdermann, P Berghaus, D Berley, E Bernardini, D Bertrand, DZ Besson, D Bindig, M Bissok, E Blaufuss, J Blumenthal, DJ Boersma, C Bohm, D Bose, S Böser, O Botner, AM Brown, S Buitink, KS Caballero-Mora, M Carson, D Chirkin, B Christy, F Clevermann, S Cohen, C Colnard, DF Cowen, AH Cruz Silva, MV D'Agostino, M Danninger, J Daughhetee, JC Davis, C De Clercq, T Degner, L Demirörs, F Descamps, P Desiati, G de Vries-Uiterweerd, T DeYoung, JC Díaz-Vélez, M Dierckxsens, J Dreyer, JP Dumm, M Dunkman, J Eisch, RW Ellsworth, O Engdegård, S Euler, PA Evenson, O Fadiran, AR Fazely, A Fedynitch, J Feintzeig, T Feusels, K Filimonov, C Finley, T Fischer-Wasels, BD Fox, A Franckowiak, R Franke, TK Gaisser, J Gallagher, L Gerhardt, L Gladstone, T Glüsenkamp, A Goldschmidt, JA Goodman, D Góra, D Grant, T Griesel, A Groß, S Grullon, M Gurtner, C Ha, A Haj Ismail, A Hallgren, F Halzen, K Han, K Hanson, D Heinen, K Helbing, R Hellauer, P Herquet, S Hickford, GC Hill, KD Hoffman, B Hoffmann, A Homeier, K Hoshina, W Huelsnitz, J-P Hülß, PO Hulth, K Hultqvist, S Hussain, A Ishihara, E Jacobi, J Jacobsen, GS Japaridze, H Johansson, K-H Kampert, A Kappes, T Karg, A Karle, P Kenny, J Kiryluk, F Kislat, SR Klein, J-H Köhne, G Kohnen, H Kolanoski, L Köpke, S Kopper, DJ Koskinen, M Kowalski, T Kowarik, M Krasberg, G Kroll, N Kurahashi, T Kuwabara, M Labare, K Laihem, H Landsman, MJ Larson, R Lauer, J Lünemann, J Madsen, A Marotta, R Maruyama, K Mase, HS Matis, K Meagher, M Merck, P Mészáros, T Meures, S Miarecki, E Middell, N Milke, J Miller, T Montaruli, R Morse, SM Movit, R Nahnhauer, JW Nam, U Naumann, DR Nygren, S Odrowski, A Olivas, M Olivo, A O'Murchadha, S Panknin, L Paul, C Pérez de los Heros, J Petrovic, A Piegsa, D Pieloth, R Porrata, J Posselt, PB Price, GT Przybylski, K Rawlins, P Redl, E Resconi, W Rhode, M Ribordy, M Richman, JP Rodrigues, F Rothmaier, C Rott, T Ruhe, D Rutledge, B Ruzybayev, D Ryckbosch, H-G Sander, M Santander, S Sarkar, K Schatto, T Schmidt, A Schönwald, A Schukraft, A Schultes, O Schulz, M Schunck, D Seckel, B Semburg, SH Seo, Y Sestayo, S Seunarine, A Silvestri, GM Spiczak, C Spiering, M Stamatikos, T Stanev, T Stezelberger, RG Stokstad, A Stössl, EA Strahler, R Ström, M Stüer, GW Sullivan, Q Swillens, H Taavola, I Taboada, A Tamburro, S Ter-Antonyan, S Tilav, PA Toale, S Toscano, D Tosi, N van Eijndhoven, J Vandenbroucke, A Van Overloop, J van Santen, M Vehring, M Voge, C Walck, T Waldenmaier, M Wallraff, M Walter, Ch Weaver, C Wendt, S Westerhoff, N Whitehorn, K Wiebe, CH Wiebusch, DR Williams, R Wischnewski, H Wissing, M Wolf, TR Wood, K Woschnagg, C Xu, DL Xu, XW Xu, JP Yanez, G Yodh, S Yoshida, P Zarzhitsky, M Zoll The ROTSE Collaboration, CW Akerlof, SB Pandey, F Yuan, W Zheng

Abstract:

Context. Transient neutrino sources such as Gamma-Ray Bursts (GRBs) and Supernovae (SNe) are hypothesized to emit bursts of high-energy neutrinos on a time-scale of \lesssim 100 s. While GRB neutrinos would be produced in high relativistic jets, core-collapse SNe might host soft-relativistic jets, which become stalled in the outer layers of the progenitor star leading to an efficient production of high-energy neutrinos. Aims. To increase the sensitivity to these neutrinos and identify their sources, a low-threshold optical follow-up program for neutrino multiplets detected with the IceCube observatory has been implemented. Methods. If a neutrino multiplet, i.e. two or more neutrinos from the same direction within 100 s, is found by IceCube a trigger is sent to the Robotic Optical Transient Search Experiment, ROTSE. The 4 ROTSE telescopes immediately start an observation program of the corresponding region of the sky in order to detect an optical counterpart to the neutrino events. Results. No statistically significant excess in the rate of neutrino multiplets has been observed and furthermore no coincidence with an optical counterpart was found. Conclusion. The search allows, for the first time, to set stringent limits on current models predicting a high-energy neutrino flux from soft relativistic hadronic jets in core-collapse SNe. We conclude that a sub-population of SNe with typical Lorentz boost factor and jet energy of 10 and 3\times10^{51} erg, respectively, does not exceed 4.2% at 90% confidence.

The effect of the geomagnetic field on cosmic ray energy estimates and large scale anisotropy searches on data from the Pierre Auger Observatory

ArXiv 1111.7122 (2011)

Authors:

P Abreu, M Aglietta, EJ Ahn, IFM Albuquerque, D Allard, I Allekotte, J Allen, P Allison, J Alvarez Castillo, J Alvarez-Muñiz, M Ambrosio, A Aminaei, L Anchordoqui, S Andringa, T Antičić, A Anzalone, C Aramo, E Arganda, F Arqueros, H Asorey, P Assis, J Aublin, M Ave, M Avenier, G Avila, T Bäcker, M Balzer, KB Barber, AF Barbosa, R Bardenet, SLC Barroso, B Baughman, J Bäuml, JJ Beatty, BR Becker, KH Becker, A Bellétoile, JA Bellido, S BenZvi, C Berat, X Bertou, PL Biermann, P Billoir, F Blanco, M Blanco, C Bleve, H Blümer, M Boháčová, D Boncioli, C Bonifazi, R Bonino, N Borodai, J Brack, P Brogueira, WC Brown, R Bruijn, P Buchholz, A Bueno, RE Burton, KS Caballero-Mora, L Caramete, R Caruso, A Castellina, O Catalano, G Cataldi, L Cazon, R Cester, J Chauvin, SH Cheng, A Chiavassa, JA Chinellato, A Chou, J Chudoba, RW Clay, MR Coluccia, R Conceição, F Contreras, H Cook, MJ Cooper, J Coppens, A Cordier, S Coutu, CE Covault, A Creusot, A Criss, J Cronin, A Curutiu, S Dagoret-Campagne, R Dallier, S Dasso, 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, M del Río, O Deligny, H Dembinski, N Dhital, C Di Giulio, JC Diaz, ML Díaz Castro, PN Diep, C Dobrigkeit, W Docters, JC D'Olivo, PN Dong, A Dorofeev, JC dos Anjos, MT Dova, D D'Urso, I Dutan, J Ebr, R Engel, M Erdmann, CO Escobar, J Espadanal, A Etchegoyen, P Facal San Luis, I Fajardo Tapia, H Falcke, G Farrar, AC Fauth, N Fazzini, AP Ferguson, A Ferrero, B Fick, A Filevich, A Filipčič, S Fliescher, CE Fracchiolla, ED Fraenkel, U Fröhlich, B Fuchs, R Gaior, RF Gamarra, S Gambetta, B García, D García Gámez, D Garcia-Pinto, A Gascon, H Gemmeke, K Gesterling, PL Ghia, U Giaccari, M Giller, H Glass, MS Gold, G Golup, F Gomez Albarracin, M Gómez Berisso, P Gonçalves, D Gonzalez, JG Gonzalez, B Gookin, D Góra, A Gorgi, P Gouffon, SR Gozzini, E Grashorn, S Grebe, N Griffith, M Grigat, AF Grillo, Y Guardincerri, F Guarino, GP Guedes, A Guzman, JD Hague, P Hansen, D Harari, S Harmsma, JL Harton, A Haungs, T Hebbeker, D Heck, AE Herve, C Hojvat, N Hollon, VC Holmes, P Homola, JR Hörandel, A Horneffer, M Hrabovský, T Huege, A Insolia, F Ionita, A Italiano, C Jarne, S Jiraskova, M Josebachuili, K Kadija, KH Kampert, P Karhan, P Kasper, B Kégl, B Keilhauer, A Keivani, JL Kelley, E Kemp, RM Kieckhafer, HO Klages, M Kleifges, J Kleinfeller, J Knapp, D-H Koang, K Kotera, N Krohm, O Krömer, D Kruppke-Hansen, F Kuehn, D Kuempel, JK Kulbartz, N Kunka, G La Rosa, C Lachaud, P Lautridou, MSAB Leão, D Lebrun, P Lebrun, MA Leigui de Oliveira, A Lemiere, A Letessier-Selvon, I Lhenry-Yvon, K Link, R López, A Lopez Agüera, K Louedec, J Lozano Bahilo, L Lu, A Lucero, M Ludwig, H Lyberis, MC Maccarone, C Macolino, S Maldera, D Mandat, P Mantsch, AG Mariazzi, J Marin, V Marin, IC Maris, HR Marquez Falcon, G Marsella, D Martello, L Martin, H Martinez, O Martínez Bravo, HJ Mathes, J Matthews, JAJ Matthews, G Matthiae, D Maurizio, PO Mazur, G Medina-Tanco, M Melissas, D Melo, E Menichetti, A Menshikov, P Mertsch, C Meurer, S Mićanović, MI Micheletti, W Miller, L Miramonti, L Molina-Bueno, S Mollerach, M Monasor, D Monnier Ragaigne, F Montanet, B Morales, C Morello, E Moreno, JC Moreno, C Morris, M Mostafá, CA Moura, S Mueller, MA Muller, G Müller, M Münchmeyer, R Mussa, G Navarra, JL Navarro, S Navas, P Necesal, L Nellen, A Nelles, J Neuser, PT Nhung, L Niemietz, N Nierstenhoefer, D Nitz, D Nosek, L Nožka, 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, A Parra, RD Parsons, S Pastor, T Paul, M Pech, J Pȩkala, R Pelayo, IM Pepe, L Perrone, R Pesce, E Petermann, S Petrera, P Petrinca, A Petrolini, Y Petrov, J Petrovic, C Pfendner, N Phan, R Piegaia, T Pierog, P Pieroni, M Pimenta, V Pirronello, M Platino, VH Ponce, M Pontz, P Privitera, M Prouza, EJ Quel, S Querchfeld, J Rautenberg, O Ravel, D Ravignani, B Revenu, J Ridky, S Riggi, M Risse, P Ristori, H Rivera, V Rizi, J Roberts, C Robledo, W Rodrigues de Carvalho, 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, C Rühle, F Salamida, H Salazar, G Salina, F Sánchez, CE Santo, E Santos, EM Santos, F Sarazin, B Sarkar, S Sarkar, R Sato, N Scharf, V Scherini, H Schieler, P Schiffer, A Schmidt, F Schmidt, O Scholten, H Schoorlemmer, J Schovancova, P Schovánek, F Schröder, S Schulte, D Schuster, SJ Sciutto, M Scuderi, A Segreto, M Settimo, A Shadkam, RC Shellard, I Sidelnik, G Sigl, HH Silva Lopez, A Śmiałkowski, R Šmída, GR Snow, P Sommers, J Sorokin, H Spinka, R Squartini, S Stanic, J Stapleton, J Stasielak, M Stephan, E Strazzeri, A Stutz, F Suarez, T Suomijärvi, AD Supanitsky, T Šuša, MS Sutherland, J Swain, Z Szadkowski, M Szuba, A Tamashiro, A Tapia, M Tartare, O Taşcău, CG Tavera Ruiz, R Tcaciuc, D Tegolo, NT Thao, D Thomas, J Tiffenberg, C Timmermans, DK Tiwari, 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, E Varela, B Vargas Cárdenas, JR Vázquez, RA Vázquez, D Veberič, V Verzi, J Vicha, M Videla, L Villaseñor, H Wahlberg, P Wahrlich, O Wainberg, D Walz, D Warner, AA Watson, M Weber, K Weidenhaupt, A Weindl, S Westerhoff, BJ Whelan, G Wieczorek, L Wiencke, B Wilczyńska, H Wilczyński, M Will, C Williams, T Winchen, MG Winnick, M Wommer, B Wundheiler, T Yamamoto, T Yapici, P Younk, G Yuan, A Yushkov, B Zamorano, E Zas, D Zavrtanik, M Zavrtanik, I Zaw, A Zepeda, M Zimbres Silva, M Ziolkowski

Abstract:

We present a comprehensive study of the influence of the geomagnetic field on the energy estimation of extensive air showers with a zenith angle smaller than $60^\circ$, detected at the Pierre Auger Observatory. The geomagnetic field induces an azimuthal modulation of the estimated energy of cosmic rays up to the ~2% level at large zenith angles. We present a method to account for this modulation of the reconstructed energy. We analyse the effect of the modulation on large scale anisotropy searches in the arrival direction distributions of cosmic rays. At a given energy, the geomagnetic effect is shown to induce a pseudo-dipolar pattern at the percent level in the declination distribution that needs to be accounted for.

Trigger and Aperture of the Surface Detector Array of the Pierre Auger Observatory

ArXiv 1111.6764 (2011)

Authors:

J Abraham, P Abreu, M Aglietta, C Aguirre, EJ Ahn, D Allard, I Allekotte, J Allen, J Alvarez-Muñiz, M Ambrosio, L Anchordoqui, S Andringa, A Anzalone, C Aramo, E Arganda, S Argirò, K Arisaka, F Arneodo, F Arqueros, T Asch, H Asorey, P Assis, J Aublin, M Ave, G Avila, T Bäcker, D Badagnani, KB Barber, AF Barbosa, SLC Barroso, B Baughman, P Bauleo, JJ Beatty, T Beau, BR Becker, KH Becker, A Bellétoile, JA Bellido, S BenZvi, C Berat, P Bernardini, X Bertou, PL Biermann, P Billoir, O Blanch-Bigas, F Blanco, C Bleve, H Blümer, M Boháčová, 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, W Carvalho, A Castellina, O Catalano, L Cazon, R Cester, J Chauvin, A Chiavassa, JA Chinellato, A Chou, J Chudoba, J Chye, 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, 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, PN Diep, C Dobrigkeit, JC D'Olivo, PN Dong, A Dorofeev, JC dos Anjos, MT Dova, D D'Urso, I Dutan, MA DuVernois, R Engel, 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 Filipčič, I Fleck, S Fliescher, CE Fracchiolla, ED Fraenkel, 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, M Gonçalves do Amaral, 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, J Gutiérrez, JD Hague, V Halenka, P Hansen, D Harari, S Harmsma, JL Harton, A Haungs, 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, S Jiraskova, 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 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, M Leuthold, I Lhenry-Yvon, R López, A Lopez Agüera, K Louedec, J Lozano Bahilo, A Lucero, H Lyberis, MC Maccarone, C Macolino, S Maldera, D Mandat, P Mantsch, AG Mariazzi, IC Maris, HR Marquez Falcon, D Martello, O Martínez Bravo, HJ Mathes, J Matthews, JAJ Matthews, G Matthiae, D Maurizio, PO Mazur, M McEwen, RR McNeil, G Medina-Tanco, M Melissas, D Melo, E Menichetti, A Menshikov, R Meyhandan, MI Micheletti, G Miele, W Miller, L Miramonti, S Mollerach, M Monasor, D Monnier Ragaigne, F Montanet, B Morales, C Morello, JC Moreno, C Morris, M Mostafá, CA Moura, S Mueller, 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 Nožka, M Nyklicek, J Oehlschläger, A Olinto, P Oliva, VM Olmos-Gilbaja, M Ortiz, 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 Pȩkala, 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, T Pinto, V Pirronello, O Pisanti, M Platino, J Pochon, 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, 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, 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, RC Shellard, I Sidelnik, BB Siffert, G Sigl, A Śmiałkowski, R Šmída, BE Smith, GR Snow, P Sommers, J Sorokin, H Spinka, R Squartini, E Strazzeri, A Stutz, F Suarez, T Suomijärvi, AD Supanitsky, MS Sutherland, J Swain, Z Szadkowski, A Tamashiro, A Tamburro, T Tarutina, O Taşcău, R Tcaciuc, D Tcherniakhovski, D Tegolo, NT Thao, D Thomas, R Ticona, J Tiffenberg, C Timmermans, W Tkaczyk, CJ Todero Peixoto, B Tomé, A Tonachini, I Torres, 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 Veberič, A Velarde, 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 Wileman, MG Winnick, H Wu, B Wundheiler, T Yamamoto, P Younk, G Yuan, A Yushkov, E Zas, D Zavrtanik, M Zavrtanik, I Zaw, A Zepeda, M Ziolkowski

Abstract:

The surface detector array of the Pierre Auger Observatory consists of 1600 water-Cherenkov detectors, for the study of extensive air showers (EAS) generated by ultra-high-energy cosmic rays. We describe the trigger hierarchy, from the identification of candidate showers at the level of a single detector, amongst a large background (mainly random single cosmic ray muons), up to the selection of real events and the rejection of random coincidences. Such trigger makes the surface detector array fully efficient for the detection of EAS with energy above $3\times 10^{18}$ eV, for all zenith angles between 0$^\circ$ and 60$^\circ$, independently of the position of the impact point and of the mass of the primary particle. In these range of energies and angles, the exposure of the surface array can be determined purely on the basis of the geometrical acceptance.