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

THE PIERRE AUGER COLLABORATION, A TAMASHIRO

PHYSICAL REVIEW LETTERS

APS

Año: 2008 vol. 100 p. 211101 - 211101

0031-9007

The surface detector array of the Pierre Auger Observatory is sensitive to Earth-skimming tau-neutrinos $ u_ au$ that interact in the Earth´s crust. Tau leptons from $ u_ au$ 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 is used to place an upper limit on the diffuse flux of $ u_ au$ at EeV energies. Assuming an $E_ u^{-2}$ differential energy spectrum the limit set at 90 % C.L. is $E_ u^{2} mathrm{d}N_{ u_ au}/mathrm{d}E_{ u} < 1.3 imes 10^{-7}$ GeV cm$^{-2}$ s$^{-1}$ sr$^{-1}$ in the energy range $2 imes10^{17} mathrm{eV} < E_ u < 2 imes10^{19}$ eV.