The Search for Ultra-High Energy Neutrinos through Highly Inclined Air Showers in the Pierre Auger Observatory

Abstract

The Surface Detector of the Pierre Auger Observatory for the detection of ultra-high energy cosmic rays, an array of 1600 water-Cherenkov stations in a triangular grid with 1500 m separation between stations, has also the capability to detect neutrinos with energy above 1017eV. The identification, through the special characteristics of highly inclined showers, is efficiently performed for neutrinos of all flavours interacting deep in the atmosphere at large zenith angles as well as for τ-neutrinos skimming the Earth crust. In this talk I review the status of the neutrino search at the Observatory using about 15 years of data. Restrictive upper bounds on the neutrino flux from diffuse sources and from point-like steady sources were stablished, placing strong constraints on several models of neutrino production at EeV energies and on the properties of the sources of ultra-high-energy cosmic rays. Unrivaled sensitivity in searches for transient sources has been also achieved.