Possible Tau Appearance Experiment with Atmospheric Neutrinos

We suggest an experimental measurement that could detect the appearance of tau neutrinos due to ${\nu }_{\mu }\to {\nu }_{\tau }$ oscillations of atmospheric neutrinos by measuring the energy spectra of neutrino induced showers. $\tau$ neutrinos deposit a large fraction of their energy in showers generated by ${\nu }_{\tau }$ charge current interactions and the subsequent $\tau$-lepton decay. The appearance of ${\nu }_{\tau }$ will enhance the spectrum of neutrino induced showers in energy ranges corresponding to the neutrino oscillation parameters. A shower rate lower than the “no oscillation” prediction is an indication for ${\nu }_{\mu }\to {\nu }_s$ oscillations.