Upper Limit on the Diffuse Flux of Ultrahigh Energy Tau Neutrinos from the Pierre Auger Observatory

AUGER COLLABORATION, F. SANCHEZ

PHYSICAL REVIEW LETTERS

APS

Año: 2008 p. 2111011 - 2111017

0031-9007

The surface detector array of the Pierre Auger Observatory is sensitive to Earth-skimming tau neutrinos that interact in Earth’s crust. Tau leptons from nu_tau charged-current interactions can emerge and decay in the atmosphere to produce a nearly horizontal shower with a significant electromagnetic component. The data collected between 1 January 2004 and 31 August 2007 are used to place an upper limit on the diffuse flux of nu_tau at EeV energies. Assuming an E_nu^-2 differential energy spectrum the limit set at 90% C.L. is E_nu^2 dN_nu_tau/dE_nu < 1.3 x 10-7 GeV cm^-2 s^-1 sr-1 in the energy range 2 x 10^17 eV