Search for ultrahigh energy neutrinos in highly inclined events at the Pierre Auger Observatory

THE PIERRE AUGER COLLABORATION.; S. J. SCIUTTO

PHYSICAL REVIEW D

AMER PHYSICAL SOC

Lugar: New York; Año: 2011 vol. 84 p. 122005 - 122021

1550-7998

The Surface Detector of the Pierre Auger Observatory is sensitive to neutrinos of all flavors above0.1 EeV. These interact through charged and neutral currents in the atmosphere giving rise to extensive airshowers. When interacting deeply in the atmosphere at nearly horizontal incidence, neutrinos can bedistinguished from regular hadronic cosmic rays by the broad time structure of their shower signals in thewater-Cherenkov detectors. In this paper we present for the first time an analysis based on down-goingneutrinos. We describe the search procedure, the possible sources of background, the method to computethe exposure and the associated systematic uncertainties. No candidate neutrinos have been found in datacollected from 1 January 2004 to 31 May 2010. Assuming an E
2 differential energy spectrum the limit onthe single-flavor neutrino is E2dN=dE<1:74  10
7GeVcm
2s
1sr
1 at 90% C.L. in the energy range1  1017eV<E<1  1020eV.