Detecting tau-neutrino appearance in the spectra of quasielastic CC events

A method for detecting the transition numu->nutau in long-baseline accelerator experiments, that consists in comparing the far-to-near ratios of the spectra of quasielastic CC events generated by high- and low-energy beams of muon neutrinos, is proposed. The test may be accessible to big calorimeters with muon spectrometry like MINOS, and is limited by statistics rather than systematics.