RT Journal Article T1 Search for ultrahigh energy neutrinos in highly inclined events at the Pierre Auger Observatory A1 Arganda, E. A1 Arqueros Martínez, Fernando A1 Blanco Ramos, Francisco A1 García Pinto, Diego A1 Ortiz Ramis, Montserrat A1 Rosado Vélez, Jaime A1 Vázquez Peñas, José Ramón AB The Surface Detector of the Pierre Auger Observatory is sensitive to neutrinos of all flavors above 0.1 EeV. These interact through charged and neutral currents in the atmosphere giving rise to extensive air showers. When interacting deeply in the atmosphere at nearly horizontal incidence, neutrinos can be distinguished from regular hadronic cosmic rays by the broad time structure of their shower signals in the water-Cherenkov detectors. In this paper we present for the first time an analysis based on down-going neutrinos. We describe the search procedure, the possible sources of background, the method to compute the exposure and the associated systematic uncertainties. No candidate neutrinos have been found in data collected from 1 January 2004 to 31 May 2010. Assuming an E-2 differential energy spectrum the limit on the single-flavor neutrino is E(2)dN/dE < 1.74 x 10(-7)GeVcm(-2)s(-1)sr(-1) at 90% C.L. in the energy range 1 x 10(17) eV < E < 1 x 10(20)eV. PB Amer Physical Soc SN 1550-7998 YR 2011 FD 2011-12-30 LK https://hdl.handle.net/20.500.14352/45087 UL https://hdl.handle.net/20.500.14352/45087 LA eng NO © 2011 American Physical Society.Artículo firmado por más de 10 autores. Pierre Auger Collaboration.The successful installation, commissioning and operation of the Pierre Auger Observatory would not have been possible without the strong commitment and effort from the technical and administrative staff in Malargue. We are very grateful to the following agencies and organizations for financial support: Comision Nacional de Energia Atomica, Fundacion Antorchas, Gobierno De La Provincia de Mendoza, Municipalidad de Malargue, NDM Holdings, and Valle Las Lenas, in gratitude for their continuing cooperation over land access, Argentina; the Australian Research Council; Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq), Financiadora de Estudos e Projetos (FINEP), Fundacao de Amparo a Pesquisa do Estado de Rio de Janeiro (FAPERJ), Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP), Ministerio de Ciencia e Tecnologia (MCT), Brazil; AVCR AV0Z10100502 and AV0Z10100522, GAAV KJB100100904, MSMT-CR LA08016, LC527, 1M06002, and MSM0021620859, Czech Republic; Centre de Calcul IN2P3/CNRS, Centre National de la Recherche Scientifique (CNRS), Conseil Regional Ile-de-France, Departement Physique Nucleaire et Corpusculaire (PNC-IN2P3/CNRS), Departement Sciences de l'Univers (SDU-INSU/CNRS), France; Bundesministerium fur Bildung und Forschung (BMBF), Deutsche Forschungsgemeinschaft (DFG), Finanzministerium Baden-Wurttemberg, Helmholtz-Gemeinschaft Deutscher Forschungszentren (HGF), Ministerium fur Wissenschaft und Forschung, Nordrhein-Westfalen, Ministerium fur Wissenschaft, Forschung und Kunst, Baden-Wurttemberg, Germany; Istituto Nazionale di Fisica Nucleare (INFN), Ministero dell'Istruzione, dell'Universita e della Ricerca (MIUR), Italy; Consejo Nacional de Ciencia y Tecnologia (CONACYT), Mexico; Ministerie van Onderwijs, Cultuur en Wetenschap, Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO), Stichting voor Fundamenteel Onderzoek der Materie (FOM), Netherlands; Ministry of Science and Higher Education, Grant Nos. 1 P03 D 014 30, N202 090 31/0623, and PAP/218/2006, Poland; Fundacao para a Ciencia e a Tecnologia, Portugal; Ministry for Higher Education, Science, and Technology, Slovenian Research Agency, Slovenia; Comunidad de Madrid, Consejeria de Educacion de la Comunidad de Castilla La Mancha, FEDER funds, Ministerio de Ciencia e Innovacion and Consolider-Ingenio 2010 (CPAN), Xunta de Galicia, Spain; Science and Technology Facilities Council, United Kingdom; U. S. Department of Energy, Contract Nos. DE-AC02-07CH11359, DE-FR02-04ER41300, National Science Foundation, Grant No. 0450696, The Grainger Foundation USA; ALFA-EC / HELEN, European Union 6th Framework Program, Grant No. MEIF-CT-2005-025057, European Union 7th Framework Program, Grant No. PIEF-GA-2008-220240, and UNESCO. NO Unión Europea. FP7 NO Ministerio de Ciencia e Innovación (MICINN) NO AVCR NO Czech Republic NO Centre de Calcul NO Centre National de la Recherche Scientifique (CNRS) NO Conseil Regional Ile-de-France NO Departement Physique Nucleaire et Corpusculaire NO Departement Sciences de l'Univers (SDU-INSU/CNRS), France NO Bundesministerium fur Bildung und Forschung (BMBF) NO Deutsche Forschungsgemeinschaft (DFG) NO Finanzministerium Baden-Wurttemberg NO Helmholtz-Gemeinschaft Deutscher Forschungszentren (HGF) NO Ministerium fur Wissenschaft und Forschung Nordrhein-Westfalen NO Ministerium fur Wissenschaft Forschung und Kunst Baden-Wurttemberg, Germany NO Istituto Nazionale di Fisica Nucleare (INFN) NO Ministero dell'Istruzione, dell'Universita e della Ricerca (MIUR), Italy NO Ministerie van Onderwijs, Cultuur en Wetenschap , Netherlands NO Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO) NO Stichting voor Fundamenteel Onderzoek der Materie (FOM), Netherlands NO Ministry of Science and Higher Education, Poland NO Fundacao para a Ciencia e a Tecnologia, Portugal NO Ministry for Higher Education, Science, and Technology, Slovenian Research Agency, Slovenia NO Comunidad de Madrid, Consejeria de Educacion de la Comunidad de Castilla La Mancha NO FEDER funds, Spain NO Xunta de Galicia, Spain NO Science and Technology Facilities Council, United Kingdom NO ALFA-EC / HELEN NO UNESCO DS Docta Complutense RD 25 abr 2025